Ability to combine multiple response projections #985 (#1031)

src/main/java/com/kobylynskyi/graphql/codegen/model/graphql/GraphQLParametrizedInput.java

@@ -5,4 +5,6 @@ package com.kobylynskyi.graphql.codegen.model.graphql;
  */
 public interface GraphQLParametrizedInput {
 
+    GraphQLParametrizedInput deepCopy();
+
 }

src/main/java/com/kobylynskyi/graphql/codegen/model/graphql/GraphQLResponseField.java

@@ -86,4 +86,23 @@ public class GraphQLResponseField {
     public int hashCode() {
         return Objects.hash(name, alias, parameters, projection);
     }
+
+    /**
+     * Returns a clone of the instance, having a deep copy of the parameters and projection.
+     *
+     * @return a clone (deep copy)
+     */
+    public GraphQLResponseField deepCopy() {
+        GraphQLResponseField deepCopy = new GraphQLResponseField(this.name);
+        if (this.alias != null) {
+            deepCopy.alias = this.alias;
+        }
+        if (this.parameters != null) {
+            deepCopy.parameters = this.parameters.deepCopy();
+        }
+        if (this.projection != null) {
+            deepCopy.projection = this.projection.deepCopy$();
+        }
+        return deepCopy;
+    }
 }

src/main/java/com/kobylynskyi/graphql/codegen/model/graphql/GraphQLResponseProjection.java

 package com.kobylynskyi.graphql.codegen.model.graphql;
 
-import java.util.ArrayList;
+import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.Objects;
 import java.util.StringJoiner;
 
 /**
- * The implementation class should basically contain the fields of the particular type which
- * should be returned back to the client.
+ * The implementation class should contain the fields of the particular type that should be returned to the client.
  */
 public abstract class GraphQLResponseProjection {
 
-    protected final List<GraphQLResponseField> fields = new ArrayList<>();
+    /**
+     * Contains all response projection fields, where:
+     * key - is the name+alias pair (where alias is nullable)
+     * value - is GraphQLResponseField which represents the response projection field
+     */
+    protected final Map<Pair<String, String>, GraphQLResponseField> fields = new LinkedHashMap<>();
+
+    protected GraphQLResponseProjection() {
+    }
+
+    protected GraphQLResponseProjection(GraphQLResponseProjection projection) {
+        if (projection == null) {
+            return;
+        }
+        projection.fields.values().forEach(this::add$);
+    }
+
+    protected GraphQLResponseProjection(List<? extends GraphQLResponseProjection> projections) {
+        if (projections == null) {
+            return;
+        }
+        for (GraphQLResponseProjection projection : projections) {
+            if (projection == null) {
+                continue;
+            }
+            projection.fields.values().forEach(this::add$);
+        }
+    }
+
+    @SuppressWarnings({"checkstyle:MethodName", "java:S100"})
+    public abstract GraphQLResponseProjection deepCopy$();
+
+    @SuppressWarnings({"checkstyle:MethodName", "java:S100", "java:S3824"})
+    protected void add$(GraphQLResponseField responseField) {
+        Pair<String, String> nameAndAlias = new Pair<>(responseField.getName(), responseField.getAlias());
+        GraphQLResponseField existingResponseField = fields.get(nameAndAlias);
+        if (existingResponseField == null) {
+            fields.put(nameAndAlias, responseField.deepCopy());
+            return;
+        }
+
+        if (!Objects.equals(responseField.getParameters(), existingResponseField.getParameters())) {
+            throw new IllegalArgumentException(
+                    String.format("Field '%s' has an argument conflict", existingResponseField.getName()));
+        }
+
+        if (responseField.getAlias() != null) {
+            existingResponseField.alias(responseField.getAlias());
+        }
+        if (responseField.getParameters() != null) {
+            existingResponseField.parameters(responseField.getParameters().deepCopy());
+        }
+        if (responseField.getProjection() != null) {
+            GraphQLResponseProjection projectionCopy = responseField.getProjection().deepCopy$();
+            if (existingResponseField.getProjection() != null) {
+                for (GraphQLResponseField field : projectionCopy.fields.values()) {
+                    existingResponseField.getProjection().add$(field);
+                }
+            } else {
+                existingResponseField.projection(projectionCopy);
+            }
+        }
+    }
 
     @Override
     public String toString() {
@@ -18,7 +81,10 @@ public abstract class GraphQLResponseProjection {
             return "";
         }
         StringJoiner joiner = new StringJoiner(" ", "{ ", " }");
-        fields.forEach(field -> joiner.add(field.toString()));
+        for (GraphQLResponseField value : fields.values()) {
+            joiner.add(value.toString());
+        }
         return joiner.toString();
     }
+
 }

src/main/java/com/kobylynskyi/graphql/codegen/model/graphql/Pair.java

+package com.kobylynskyi.graphql.codegen.model.graphql;
+
+import java.util.Objects;
+
+/**
+ * Class that represents a key-value pair.
+ *
+ * @param <K> key
+ * @param <V> value
+ */
+public class Pair<K, V> {
+
+    private final K key;
+    private final V value;
+
+    public K getKey() {
+        return key;
+    }
+
+    public V getValue() {
+        return value;
+    }
+
+    public Pair(K key, V value) {
+        this.key = key;
+        this.value = value;
+    }
+
+    @Override
+    public String toString() {
+        return key + "=" + value;
+    }
+
+    @Override
+    public int hashCode() {
+        return key.hashCode() * 13 + (value == null ? 0 : value.hashCode());
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o instanceof Pair) {
+            Pair<?, ?> pair = (Pair<?, ?>) o;
+            return Objects.equals(key, pair.key) && Objects.equals(value, pair.value);
+        }
+        return false;
+    }
+}

src/main/resources/templates/java-lang/parametrized_input.ftl

@@ -70,6 +70,17 @@ public class ${className} implements GraphQLParametrizedInput {
 
 </#list>
 </#if>
+    @Override
+    public ${className} deepCopy() {
+        ${className} parametrizedInput = new ${className}();
+        <#if fields?has_content>
+        <#list fields as field>
+        parametrizedInput.${field.name}(this.${field.name});
+        </#list>
+        </#if>
+        return parametrizedInput;
+    }
+
 <#if equalsAndHashCode>
     @Override
     public boolean equals(Object obj) {

src/main/resources/templates/java-lang/response_projection.ftl

@@ -8,6 +8,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
 </#if>
+import java.util.List;
 <#if equalsAndHashCode>
 import java.util.Objects;
 </#if>
@@ -36,6 +37,14 @@ public class ${className} extends GraphQLResponseProjection {
 
     public ${className}() {
     }
+
+    public ${className}(${className} projection) {
+        super(projection);
+    }
+
+    public ${className}(List<${className}> projections) {
+        super(projections);
+    }
 <#if fields?has_content && generateAllMethodInProjection>
 
     public ${className} all$() {
@@ -76,7 +85,7 @@ public class ${className} extends GraphQLResponseProjection {
     }
 
     public ${className} ${field.methodName}(String alias<#if field.type?has_content>, ${field.type} subProjection</#if>) {
-        fields.add(new GraphQLResponseField("${field.name}").alias(alias)<#if field.type?has_content>.projection(subProjection)</#if>);
+        add$(new GraphQLResponseField("${field.name}").alias(alias)<#if field.type?has_content>.projection(subProjection)</#if>);
         return this;
     }
 
@@ -86,13 +95,18 @@ public class ${className} extends GraphQLResponseProjection {
     }
 
     public ${className} ${field.methodName}(String alias, ${field.parametrizedInputClassName} input<#if field.type?has_content>, ${field.type} subProjection</#if>) {
-        fields.add(new GraphQLResponseField("${field.name}").alias(alias).parameters(input)<#if field.type?has_content>.projection(subProjection)</#if>);
+        add$(new GraphQLResponseField("${field.name}").alias(alias).parameters(input)<#if field.type?has_content>.projection(subProjection)</#if>);
         return this;
     }
 
 </#if>
 </#list>
 </#if>
+    @Override
+    public ${className} deepCopy$() {
+        return new ${className}(this);
+    }
+
 <#if equalsAndHashCode>
     @Override
     public boolean equals(Object obj) {

src/main/resources/templates/kotlin-lang/parametrized_input.ftl

@@ -38,6 +38,19 @@ data class ${className}(
 </#if>
 ) : GraphQLParametrizedInput {
 
+    override fun deepCopy(): ${className} {
+    <#if fields?has_content>
+        return ${className}(
+        <#list fields as field>
+            this.${field.name}<#if field_has_next>,</#if>
+        </#list>
+        )
+    <#else>
+        return ${className}()
+    </#if>
+    
+    }
+
     override fun toString(): String {
         val joiner = StringJoiner(", ", "( ", " )")
         <#list fields as field>

src/main/resources/templates/kotlin-lang/response_projection.ftl

@@ -24,7 +24,13 @@ import java.util.Objects
 <#list annotations as annotation>
 @${annotation}
 </#list>
-open class ${className} : GraphQLResponseProjection() {
+open class ${className} : GraphQLResponseProjection {
+
+    constructor(): super()
+
+    constructor(projection: ${className}): super(projection)
+
+    constructor(projections: List<${className}>): super(projections)
 
 <#if fields?has_content && generateAllMethodInProjection>
     private val projectionDepthOnFields: MutableMap<String, Int> by lazy { mutableMapOf<String, Int>() }
@@ -63,7 +69,7 @@ open class ${className} : GraphQLResponseProjection() {
     fun ${field.methodName}(<#if field.type?has_content>subProjection: ${field.type}</#if>): ${className} = ${field.methodName}(<#if field.parametrizedInputClassName?has_content></#if>null<#if field.type?has_content>, subProjection</#if>)
 
     fun ${field.methodName}(alias: String?<#if field.type?has_content>, subProjection: ${field.type}</#if>): ${className} {
-        fields.add(GraphQLResponseField("${field.name}").alias(alias)<#if field.type?has_content>.projection(subProjection)</#if>)
+        `add$`(GraphQLResponseField("${field.name}").alias(alias)<#if field.type?has_content>.projection(subProjection)</#if>)
         return this
     }
 
@@ -71,13 +77,15 @@ open class ${className} : GraphQLResponseProjection() {
     fun ${field.methodName}(input: ${field.parametrizedInputClassName}<#if field.type?has_content>, subProjection: ${field.type}</#if>): ${className} = ${field.methodName}(null, input<#if field.type?has_content>, subProjection</#if>)
 
     fun ${field.methodName}(alias: String?, input: ${field.parametrizedInputClassName}<#if field.type?has_content>, subProjection: ${field.type}</#if>): ${className} {
-        fields.add(GraphQLResponseField("${field.name}").alias(alias).parameters(input)<#if field.type?has_content>.projection(subProjection)</#if>)
+        `add$`(GraphQLResponseField("${field.name}").alias(alias).parameters(input)<#if field.type?has_content>.projection(subProjection)</#if>)
         return this
     }
 
 </#if>
 </#list>
 </#if>
+    override fun `deepCopy$`(): ${className} = ${className}(this)
+
 <#if equalsAndHashCode>
     override fun equals(other: Any?): Boolean {
         if (this === other) {

src/main/resources/templates/scala-lang/parametrized_input.ftl

@@ -54,6 +54,18 @@ case class ${className}(
 </#if>
 ) extends GraphQLParametrizedInput {
 
+    override def deepCopy(): ${className} = {
+    <#if fields?has_content>
+        ${className}(
+        <#list fields as field>
+            this.${field.name}<#if field_has_next>,</#if>
+        </#list>
+        )
+    <#else>
+        ${className}()
+    </#if>
+    }
+
     override def toString(): String = {<#--There is no Option[Seq[T]], Format is not supported in the generated code, so it is very difficult to write template for this format.-->
     <#if fields?has_content>
         scala.Seq(<#list fields as field><#assign getMethod = ".get"><#assign asJava = ".asJava">

src/main/resources/templates/scala-lang/response_projection.ftl

@@ -10,6 +10,7 @@ import java.util.Objects
 <#if fields?has_content && generateAllMethodInProjection>
 import scala.collection.mutable.HashMap
 </#if>
+import scala.collection.JavaConverters._
 
 <#if javaDoc?has_content>
 /**
@@ -27,7 +28,29 @@ import scala.collection.mutable.HashMap
 <#list annotations as annotation>
 @${annotation}
 </#list>
-class ${className} extends GraphQLResponseProjection {
+class ${className}() extends GraphQLResponseProjection() {
+
+    def this(projection: ${className}) = {
+        this()
+        if (projection != null) {
+            for (field <- projection.fields.values.asScala) {
+                add$(field)
+            }
+        }
+    }
+
+    def this(projections: scala.Seq[${className}]) = {
+        this()
+        if (projections != null) {
+            for (projection <- projections) {
+                if (projection != null) {
+                    for (field <- projection.fields.values.asScala) {
+                        add$(field)
+                    }
+                }
+            }
+        }
+    }
 
 <#if fields?has_content && generateAllMethodInProjection>
     private final lazy val projectionDepthOnFields = new HashMap[String, Int]
@@ -68,7 +91,7 @@ class ${className} extends GraphQLResponseProjection {
     }
 
     def ${field.methodName}(alias: String<#if field.type?has_content>, subProjection: ${field.type}</#if>): ${className} = {
-        fields.add(new GraphQLResponseField("${field.name}").alias(alias)<#if field.type?has_content>.projection(subProjection)</#if>)
+        add$(new GraphQLResponseField("${field.name}").alias(alias)<#if field.type?has_content>.projection(subProjection)</#if>)
         this
     }
 
@@ -78,13 +101,15 @@ class ${className} extends GraphQLResponseProjection {
     }
 
     def ${field.methodName}(alias: String, input: ${field.parametrizedInputClassName} <#if field.type?has_content>, subProjection: ${field.type}</#if>): ${className} = {
-        fields.add(new GraphQLResponseField("${field.name}").alias(alias).parameters(input)<#if field.type?has_content>.projection(subProjection)</#if>)
+        add$(new GraphQLResponseField("${field.name}").alias(alias).parameters(input)<#if field.type?has_content>.projection(subProjection)</#if>)
         this
     }
 
 </#if>
 </#list>
 </#if>
+    override def deepCopy$(): ${className} = new ${className}(this)
+
 <#if equalsAndHashCode>
     override def equals(obj: Any): Boolean = {
         if (this == obj) {

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/GraphQLResponseProjectionTest.java

+package com.kobylynskyi.graphql.codegen.model.graphql;
+
+import com.kobylynskyi.graphql.codegen.model.graphql.data.EventPropertyChildParametrizedInput;
+import com.kobylynskyi.graphql.codegen.model.graphql.data.EventPropertyResponseProjection;
+import com.kobylynskyi.graphql.codegen.model.graphql.data.EventResponseProjection;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.singletonList;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
+class GraphQLResponseProjectionTest {
+
+    @Test
+    public void deepCopy_empty() {
+        EventResponseProjection original = new EventResponseProjection();
+        EventResponseProjection deepCopy = original.deepCopy$();
+        assertTrue(deepCopy.fields.isEmpty());
+    }
+
+    @Test
+    public void deepCopy_null() {
+        assertTrue(new EventResponseProjection((EventResponseProjection) null).fields.isEmpty());
+    }
+
+    @Test
+    public void deepCopy_null_list() {
+        assertTrue(new EventResponseProjection((List<EventResponseProjection>) null).fields.isEmpty());
+    }
+
+    @Test
+    public void deepCopy_empty_list() {
+        assertTrue(new EventResponseProjection(new ArrayList<>()).fields.isEmpty());
+    }
+
+    @Test
+    public void deepCopy_list_with_null_element() {
+        assertTrue(new EventResponseProjection(new ArrayList<>(singletonList(null))).fields.isEmpty());
+    }
+
+    @Test
+    public void deepCopy() {
+        EventResponseProjection original = new EventResponseProjection();
+        original.id();
+        original.status("state");
+        original.properties(new EventPropertyResponseProjection()
+                .intVal()
+                .stringVal()
+                .child(new EventPropertyChildParametrizedInput(1, 2),
+                        new EventPropertyResponseProjection()
+                                .booleanVal()));
+
+        EventResponseProjection deepCopy = original.deepCopy$();
+
+        assertEquals("{ id state : status properties { intVal stringVal child (first: 1, last: 2) { booleanVal } } }",
+                original.toString());
+        assertEquals("{ id state : status properties { intVal stringVal child (first: 1, last: 2) { booleanVal } } }",
+                deepCopy.toString());
+
+        // check that original and deepcopy are not modified
+
+        original.active();
+        deepCopy.rating();
+
+        assertEquals(
+                "{ id state : status properties { intVal stringVal child (first: 1, last: 2) { booleanVal } } active }",
+                original.toString());
+        assertEquals(
+                "{ id state : status properties { intVal stringVal child (first: 1, last: 2) { booleanVal } } rating }",
+                deepCopy.toString());
+    }
+
+    @Test
+    public void join() {
+        EventResponseProjection projection1 = new EventResponseProjection();
+        projection1.id();
+        projection1.status("state");
+        projection1.rating();
+        projection1.properties(new EventPropertyResponseProjection()
+                .intVal()
+                .stringVal()
+                .child("child12", new EventPropertyChildParametrizedInput(1, 2),
+                        new EventPropertyResponseProjection()
+                                .booleanVal()));
+
+        EventResponseProjection projection2 = new EventResponseProjection();
+        projection2.id("uid");
+        projection2.status();
+        projection2.active();
+        projection2.properties(new EventPropertyResponseProjection()
+                .floatVal()
+                .child("child34", new EventPropertyChildParametrizedInput(3, 4),
+                        new EventPropertyResponseProjection()
+                                .intVal()));
+
+        EventResponseProjection projection12 = new EventResponseProjection(asList(projection1, projection2));
+        assertEquals("{ id state : status rating " +
+                        "properties { intVal stringVal child12 : child (first: 1, last: 2) { booleanVal } " +
+                        "floatVal child34 : child (first: 3, last: 4) { intVal } } uid : id status active }",
+                projection12.toString());
+    }
+
+    @Test
+    public void join_same_aliases_different_inputs() {
+        EventResponseProjection projection1 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child(new EventPropertyChildParametrizedInput(1, 2),
+                                new EventPropertyResponseProjection().intVal()));
+
+        EventResponseProjection projection2 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child(new EventPropertyChildParametrizedInput(3, 4),
+                                new EventPropertyResponseProjection().intVal()));
+
+        try {
+            new EventResponseProjection(asList(projection1, projection2));
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("Field 'child' has an argument conflict", e.getMessage());
+        }
+    }
+
+    @Test
+    public void join_same_aliases_different_inputs2() {
+        EventResponseProjection projection1 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child("children", new EventPropertyChildParametrizedInput(1, 2),
+                                new EventPropertyResponseProjection().intVal()));
+
+        EventResponseProjection projection2 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child("children", new EventPropertyChildParametrizedInput(3, 4),
+                                new EventPropertyResponseProjection().intVal()));
+
+        try {
+            new EventResponseProjection(asList(projection1, projection2));
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("Field 'child' has an argument conflict", e.getMessage());
+        }
+    }
+
+    @Test
+    public void join_same_aliases_different_inputs3() {
+        EventResponseProjection projection1 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child("children", new EventPropertyChildParametrizedInput(1, 2),
+                                null));
+
+        EventResponseProjection projection2 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child("children", new EventPropertyChildParametrizedInput(3, 4),
+                                new EventPropertyResponseProjection().intVal()));
+
+        try {
+            new EventResponseProjection(asList(projection1, projection2));
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("Field 'child' has an argument conflict", e.getMessage());
+        }
+    }
+
+    @Test
+    public void join_same_aliases_different_inputs4() {
+        EventResponseProjection projection1 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child("children", new EventPropertyChildParametrizedInput(1, 2),
+                                new EventPropertyResponseProjection().intVal()));
+
+        EventResponseProjection projection2 = new EventResponseProjection()
+                .properties(new EventPropertyResponseProjection()
+                        .child("children", new EventPropertyChildParametrizedInput(3, 4),
+                                null));
+
+        try {
+            new EventResponseProjection(asList(projection1, projection2));
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("Field 'child' has an argument conflict", e.getMessage());
+        }
+    }
+
+    @Test
+    public void join_null_values() {
+        EventResponseProjection projection1 = new EventResponseProjection();
+        projection1.id(null);
+        projection1.properties(null);
+
+        EventResponseProjection projection2 = new EventResponseProjection();
+        projection2.properties(new EventPropertyResponseProjection()
+                .child(null));
+
+        EventResponseProjection projection3 = new EventResponseProjection();
+        projection2.properties(new EventPropertyResponseProjection()
+                .child(null, null, new EventPropertyResponseProjection()
+                        .child(null)));
+
+        EventResponseProjection projection123 = new EventResponseProjection(
+                asList(projection1, projection2, projection3));
+        assertEquals("{ id properties { child { child } } }",
+                projection123.toString());
+    }
+
+}
\ No newline at end of file

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/EventPropertyChildParametrizedInput.java

@@ -62,4 +62,11 @@ public class EventPropertyChildParametrizedInput implements GraphQLParametrizedI
         return joiner.toString();
     }
 
+    @Override
+    public EventPropertyChildParametrizedInput deepCopy() {
+        EventPropertyChildParametrizedInput parametrizedInput = new EventPropertyChildParametrizedInput();
+        parametrizedInput.first(this.first);
+        parametrizedInput.last(this.last);
+        return parametrizedInput;
+    }
 }
\ No newline at end of file

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/EventPropertyParentParametrizedInput.java

@@ -62,4 +62,11 @@ public class EventPropertyParentParametrizedInput implements GraphQLParametrized
         return joiner.toString();
     }
 
+    @Override
+    public EventPropertyParentParametrizedInput deepCopy() {
+        EventPropertyParentParametrizedInput parametrizedInput = new EventPropertyParentParametrizedInput();
+        parametrizedInput.withStatus(this.withStatus);
+        parametrizedInput.createdAfter(this.createdAfter);
+        return parametrizedInput;
+    }
 }

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/EventPropertyResponseProjection.java

@@ -3,12 +3,27 @@ package com.kobylynskyi.graphql.codegen.model.graphql.data;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
 /**
  * Response projection for EventProperty
  */
 public class EventPropertyResponseProjection extends GraphQLResponseProjection {
 
+    private final Map<String, Integer> projectionDepthOnFields = new HashMap<>();
+
     public EventPropertyResponseProjection() {
+        super();
+    }
+
+    public EventPropertyResponseProjection(EventPropertyResponseProjection projection) {
+        super(projection);
+    }
+
+    public EventPropertyResponseProjection(List<EventPropertyResponseProjection> projections) {
+        super(projections);
     }
 
     public EventPropertyResponseProjection floatVal() {
@@ -16,7 +31,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection floatVal(String alias) {
-        fields.add(new GraphQLResponseField("floatVal").alias(alias));
+        add$(new GraphQLResponseField("floatVal").alias(alias));
         return this;
     }
 
@@ -25,7 +40,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection booleanVal(String alias) {
-        fields.add(new GraphQLResponseField("booleanVal").alias(alias));
+        add$(new GraphQLResponseField("booleanVal").alias(alias));
         return this;
     }
 
@@ -34,7 +49,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection intVal(String alias) {
-        fields.add(new GraphQLResponseField("intVal").alias(alias));
+        add$(new GraphQLResponseField("intVal").alias(alias));
         return this;
     }
 
@@ -43,7 +58,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection stringVal(String alias) {
-        fields.add(new GraphQLResponseField("stringVal").alias(alias));
+        add$(new GraphQLResponseField("stringVal").alias(alias));
         return this;
     }
 
@@ -52,7 +67,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection child(String alias, EventPropertyResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("child").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("child").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -63,7 +78,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
 
     public EventPropertyResponseProjection child(String alias, EventPropertyChildParametrizedInput input,
                                                  EventPropertyResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("child").alias(alias).parameters(input).projection(subProjection));
+        add$(new GraphQLResponseField("child").alias(alias).parameters(input).projection(subProjection));
         return this;
     }
 
@@ -72,7 +87,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection parent(String alias, EventResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("parent").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("parent").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -83,7 +98,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
 
     public EventPropertyResponseProjection parent(String alias, EventPropertyParentParametrizedInput input,
                                                   EventResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("parent").alias(alias).parameters(input).projection(subProjection));
+        add$(new GraphQLResponseField("parent").alias(alias).parameters(input).projection(subProjection));
         return this;
     }
 
@@ -94,4 +109,9 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     public GraphQLResponseProjection all$(int maxDepth) {
         return null;
     }
+
+    @Override
+    public GraphQLResponseProjection deepCopy$() {
+        return new EventPropertyResponseProjection(this);
+    }
 }

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/EventResponseProjection.java

@@ -3,6 +3,8 @@ package com.kobylynskyi.graphql.codegen.model.graphql.data;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 
+import java.util.List;
+
 /**
  * Response projection for Event
  */
@@ -11,12 +13,20 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     public EventResponseProjection() {
     }
 
+    public EventResponseProjection(EventResponseProjection projection) {
+        super(projection);
+    }
+
+    public EventResponseProjection(List<EventResponseProjection> projections) {
+        super(projections);
+    }
+
     public EventResponseProjection id() {
         return id(null);
     }
 
     public EventResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -25,7 +35,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection categoryId(String alias) {
-        fields.add(new GraphQLResponseField("categoryId").alias(alias));
+        add$(new GraphQLResponseField("categoryId").alias(alias));
         return this;
     }
 
@@ -34,7 +44,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection properties(String alias, EventPropertyResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("properties").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("properties").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -43,7 +53,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection status(String alias) {
-        fields.add(new GraphQLResponseField("status").alias(alias));
+        add$(new GraphQLResponseField("status").alias(alias));
         return this;
     }
 
@@ -52,7 +62,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdBy(String alias) {
-        fields.add(new GraphQLResponseField("createdBy").alias(alias));
+        add$(new GraphQLResponseField("createdBy").alias(alias));
         return this;
     }
 
@@ -61,7 +71,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdDateTime(String alias) {
-        fields.add(new GraphQLResponseField("createdDateTime").alias(alias));
+        add$(new GraphQLResponseField("createdDateTime").alias(alias));
         return this;
     }
 
@@ -70,7 +80,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection active(String alias) {
-        fields.add(new GraphQLResponseField("active").alias(alias));
+        add$(new GraphQLResponseField("active").alias(alias));
         return this;
     }
 
@@ -79,7 +89,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection rating(String alias) {
-        fields.add(new GraphQLResponseField("rating").alias(alias));
+        add$(new GraphQLResponseField("rating").alias(alias));
         return this;
     }
 
@@ -90,4 +100,9 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     public GraphQLResponseProjection all$(int maxDepth) {
         return null;
     }
+
+    @Override
+    public EventResponseProjection deepCopy$() {
+        return new EventResponseProjection(this);
+    }
 }

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/IssueResponseProjection.java

@@ -3,17 +3,27 @@ package com.kobylynskyi.graphql.codegen.model.graphql.data;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 
+import java.util.List;
+
 public class IssueResponseProjection extends GraphQLResponseProjection {
 
     public IssueResponseProjection() {
     }
 
+    public IssueResponseProjection(IssueResponseProjection projection) {
+        super(projection);
+    }
+
+    public IssueResponseProjection(List<IssueResponseProjection> projections) {
+        super(projections);
+    }
+
     public IssueResponseProjection activeLockReason() {
         return activeLockReason(null);
     }
 
     public IssueResponseProjection activeLockReason(String alias) {
-        fields.add(new GraphQLResponseField("activeLockReason").alias(alias));
+        add$(new GraphQLResponseField("activeLockReason").alias(alias));
         return this;
     }
 
@@ -24,6 +34,12 @@ public class IssueResponseProjection extends GraphQLResponseProjection {
     public GraphQLResponseProjection all$(int maxDepth) {
         return null;
     }
+
+    @Override
+    public IssueResponseProjection deepCopy$() {
+        return new IssueResponseProjection(this);
+    }
+
     // REST OF THE STUFF WAS REMOVED
 
 }

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/OrganizationResponseProjection.java

@@ -3,17 +3,27 @@ package com.kobylynskyi.graphql.codegen.model.graphql.data;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 
+import java.util.List;
+
 public class OrganizationResponseProjection extends GraphQLResponseProjection {
 
     public OrganizationResponseProjection() {
     }
 
+    public OrganizationResponseProjection(OrganizationResponseProjection projection) {
+        super(projection);
+    }
+
+    public OrganizationResponseProjection(List<OrganizationResponseProjection> projections) {
+        super(projections);
+    }
+
     public OrganizationResponseProjection name() {
         return name(null);
     }
 
     public OrganizationResponseProjection name(String alias) {
-        fields.add(new GraphQLResponseField("name").alias(alias));
+        add$(new GraphQLResponseField("name").alias(alias));
         return this;
     }
 
@@ -24,6 +34,12 @@ public class OrganizationResponseProjection extends GraphQLResponseProjection {
     public GraphQLResponseProjection all$(int maxDepth) {
         return null;
     }
+
+    @Override
+    public GraphQLResponseProjection deepCopy$() {
+        return new OrganizationResponseProjection(this);
+    }
+
     // REST OF THE STUFF WAS REMOVED
 
 }

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/UpdateIssuePayloadResponseProjection.java

@@ -3,17 +3,27 @@ package com.kobylynskyi.graphql.codegen.model.graphql.data;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 
+import java.util.List;
+
 public class UpdateIssuePayloadResponseProjection extends GraphQLResponseProjection {
 
     public UpdateIssuePayloadResponseProjection() {
     }
 
+    public UpdateIssuePayloadResponseProjection(UpdateIssuePayloadResponseProjection projection) {
+        super(projection);
+    }
+
+    public UpdateIssuePayloadResponseProjection(List<UpdateIssuePayloadResponseProjection> projections) {
+        super(projections);
+    }
+
     public UpdateIssuePayloadResponseProjection clientMutationId() {
         return clientMutationId(null);
     }
 
     public UpdateIssuePayloadResponseProjection clientMutationId(String alias) {
-        fields.add(new GraphQLResponseField("clientMutationId").alias(alias));
+        add$(new GraphQLResponseField("clientMutationId").alias(alias));
         return this;
     }
 
@@ -22,7 +32,7 @@ public class UpdateIssuePayloadResponseProjection extends GraphQLResponseProject
     }
 
     public UpdateIssuePayloadResponseProjection issue(String alias, IssueResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("issue").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("issue").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -31,7 +41,7 @@ public class UpdateIssuePayloadResponseProjection extends GraphQLResponseProject
     }
 
     public UpdateIssuePayloadResponseProjection union(String alias, UpdateNodeUnionResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("union").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("union").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -42,4 +52,11 @@ public class UpdateIssuePayloadResponseProjection extends GraphQLResponseProject
     public GraphQLResponseProjection all$(int maxDepth) {
         return null;
     }
+
+
+    @Override
+    public UpdateIssuePayloadResponseProjection deepCopy$() {
+        return new UpdateIssuePayloadResponseProjection(this);
+    }
+
 }

src/test/java/com/kobylynskyi/graphql/codegen/model/graphql/data/UpdateNodeUnionResponseProjection.java

@@ -3,6 +3,8 @@ package com.kobylynskyi.graphql.codegen.model.graphql.data;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 
+import java.util.List;
+
 /**
  * Response projection for SearchResultItem
  */
@@ -11,12 +13,20 @@ public class UpdateNodeUnionResponseProjection extends GraphQLResponseProjection
     public UpdateNodeUnionResponseProjection() {
     }
 
+    public UpdateNodeUnionResponseProjection(UpdateNodeUnionResponseProjection projection) {
+        super(projection);
+    }
+
+    public UpdateNodeUnionResponseProjection(List<UpdateNodeUnionResponseProjection> projections) {
+        super(projections);
+    }
+
     public UpdateNodeUnionResponseProjection onIssue(IssueResponseProjection subProjection) {
         return onIssue(null, subProjection);
     }
 
     public UpdateNodeUnionResponseProjection onIssue(String alias, IssueResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on Issue").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on Issue").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -26,7 +36,7 @@ public class UpdateNodeUnionResponseProjection extends GraphQLResponseProjection
 
     public UpdateNodeUnionResponseProjection onOrganization(String alias,
                                                             OrganizationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on Organization").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on Organization").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -36,7 +46,7 @@ public class UpdateNodeUnionResponseProjection extends GraphQLResponseProjection
     }
 
     public UpdateNodeUnionResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
@@ -47,4 +57,10 @@ public class UpdateNodeUnionResponseProjection extends GraphQLResponseProjection
     public GraphQLResponseProjection all$(int maxDepth) {
         return null;
     }
+
+    @Override
+    public UpdateNodeUnionResponseProjection deepCopy$() {
+        return new UpdateNodeUnionResponseProjection(this);
+    }
+
 }

src/test/resources/expected-classes/empty/EventResponseProjection.java.txt

@@ -2,6 +2,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Event
@@ -17,6 +18,14 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     public EventResponseProjection() {
     }
 
+    public EventResponseProjection(EventResponseProjection projection) {
+        super(projection);
+    }
+
+    public EventResponseProjection(List<EventResponseProjection> projections) {
+        super(projections);
+    }
+
     public EventResponseProjection all$() {
         return all$(3);
     }
@@ -31,9 +40,14 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public EventResponseProjection deepCopy$() {
+        return new EventResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/extend/request/AssetResponseProjection.java.txt

@@ -2,6 +2,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Asset
@@ -17,6 +18,14 @@ public class AssetResponseProjection extends GraphQLResponseProjection {
     public AssetResponseProjection() {
     }
 
+    public AssetResponseProjection(AssetResponseProjection projection) {
+        super(projection);
+    }
+
+    public AssetResponseProjection(List<AssetResponseProjection> projections) {
+        super(projections);
+    }
+
     public AssetResponseProjection all$() {
         return all$(3);
     }
@@ -35,7 +44,7 @@ public class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     public AssetResponseProjection name(String alias) {
-        fields.add(new GraphQLResponseField("name").alias(alias));
+        add$(new GraphQLResponseField("name").alias(alias));
         return this;
     }
 
@@ -44,7 +53,7 @@ public class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     public AssetResponseProjection status(String alias) {
-        fields.add(new GraphQLResponseField("status").alias(alias));
+        add$(new GraphQLResponseField("status").alias(alias));
         return this;
     }
 
@@ -53,7 +62,7 @@ public class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     public AssetResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -62,7 +71,7 @@ public class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     public AssetResponseProjection createdBy(String alias) {
-        fields.add(new GraphQLResponseField("createdBy").alias(alias));
+        add$(new GraphQLResponseField("createdBy").alias(alias));
         return this;
     }
 
@@ -71,9 +80,14 @@ public class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     public AssetResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public AssetResponseProjection deepCopy$() {
+        return new AssetResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/extend/request/EventResponseProjection.java.txt

@@ -2,6 +2,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Event
@@ -17,6 +18,14 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     public EventResponseProjection() {
     }
 
+    public EventResponseProjection(EventResponseProjection projection) {
+        super(projection);
+    }
+
+    public EventResponseProjection(List<EventResponseProjection> projections) {
+        super(projections);
+    }
+
     public EventResponseProjection all$() {
         return all$(3);
     }
@@ -39,7 +48,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection status(String alias) {
-        fields.add(new GraphQLResponseField("status").alias(alias));
+        add$(new GraphQLResponseField("status").alias(alias));
         return this;
     }
 
@@ -48,7 +57,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdDateTime(String alias) {
-        fields.add(new GraphQLResponseField("createdDateTime").alias(alias));
+        add$(new GraphQLResponseField("createdDateTime").alias(alias));
         return this;
     }
 
@@ -57,7 +66,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection assets(String alias, AssetResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("assets").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("assets").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -66,7 +75,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -75,7 +84,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdBy(String alias) {
-        fields.add(new GraphQLResponseField("createdBy").alias(alias));
+        add$(new GraphQLResponseField("createdBy").alias(alias));
         return this;
     }
 
@@ -84,9 +93,14 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public EventResponseProjection deepCopy$() {
+        return new EventResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/from-introspection-result/ProductResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Product
@@ -19,6 +20,14 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     public ProductResponseProjection() {
     }
 
+    public ProductResponseProjection(ProductResponseProjection projection) {
+        super(projection);
+    }
+
+    public ProductResponseProjection(List<ProductResponseProjection> projections) {
+        super(projections);
+    }
+
     public ProductResponseProjection all$() {
         return all$(3);
     }
@@ -40,7 +49,7 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -49,7 +58,7 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection title(String alias) {
-        fields.add(new GraphQLResponseField("title").alias(alias));
+        add$(new GraphQLResponseField("title").alias(alias));
         return this;
     }
 
@@ -58,7 +67,7 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection description(String alias) {
-        fields.add(new GraphQLResponseField("description").alias(alias));
+        add$(new GraphQLResponseField("description").alias(alias));
         return this;
     }
 
@@ -67,7 +76,7 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection price(String alias) {
-        fields.add(new GraphQLResponseField("price").alias(alias));
+        add$(new GraphQLResponseField("price").alias(alias));
         return this;
     }
 
@@ -76,7 +85,7 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection sku(String alias) {
-        fields.add(new GraphQLResponseField("sku").alias(alias));
+        add$(new GraphQLResponseField("sku").alias(alias));
         return this;
     }
 
@@ -85,7 +94,7 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection stockStatus(String alias) {
-        fields.add(new GraphQLResponseField("stockStatus").alias(alias));
+        add$(new GraphQLResponseField("stockStatus").alias(alias));
         return this;
     }
 
@@ -94,7 +103,7 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection addedDateTime(String alias) {
-        fields.add(new GraphQLResponseField("addedDateTime").alias(alias));
+        add$(new GraphQLResponseField("addedDateTime").alias(alias));
         return this;
     }
 
@@ -103,9 +112,14 @@ public class ProductResponseProjection extends GraphQLResponseProjection {
     }
 
     public ProductResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public ProductResponseProjection deepCopy$() {
+        return new ProductResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/kt/SearchResultItemConnectionResponseProjection.kt.txt

@@ -11,7 +11,13 @@ import java.util.Objects
     value = ["com.kobylynskyi.graphql.codegen.GraphQLCodegen"],
     date = "2020-12-31T23:59:59-0500"
 )
-open class SearchResultItemConnectionResponseProjection : GraphQLResponseProjection() {
+open class SearchResultItemConnectionResponseProjection : GraphQLResponseProjection {
+
+    constructor(): super()
+
+    constructor(projection: SearchResultItemConnectionResponseProjection): super(projection)
+
+    constructor(projections: List<SearchResultItemConnectionResponseProjection>): super(projections)
 
     private val projectionDepthOnFields: MutableMap<String, Int> by lazy { mutableMapOf<String, Int>() }
 
@@ -42,66 +48,68 @@ open class SearchResultItemConnectionResponseProjection : GraphQLResponseProject
     fun codeCount(): SearchResultItemConnectionResponseProjection = codeCount(null)
 
     fun codeCount(alias: String?): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("codeCount").alias(alias))
+        `add$`(GraphQLResponseField("codeCount").alias(alias))
         return this
     }
 
     fun edges(subProjection: SearchResultItemEdgeResponseProjection): SearchResultItemConnectionResponseProjection = edges(null, subProjection)
 
     fun edges(alias: String?, subProjection: SearchResultItemEdgeResponseProjection): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("edges").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("edges").alias(alias).projection(subProjection))
         return this
     }
 
     fun issueCount(): SearchResultItemConnectionResponseProjection = issueCount(null)
 
     fun issueCount(alias: String?): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("issueCount").alias(alias))
+        `add$`(GraphQLResponseField("issueCount").alias(alias))
         return this
     }
 
     fun nodes(subProjection: SearchResultItemResponseProjection): SearchResultItemConnectionResponseProjection = nodes(null, subProjection)
 
     fun nodes(alias: String?, subProjection: SearchResultItemResponseProjection): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("nodes").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("nodes").alias(alias).projection(subProjection))
         return this
     }
 
     fun pageInfo(subProjection: PageInfoResponseProjection): SearchResultItemConnectionResponseProjection = pageInfo(null, subProjection)
 
     fun pageInfo(alias: String?, subProjection: PageInfoResponseProjection): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("pageInfo").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("pageInfo").alias(alias).projection(subProjection))
         return this
     }
 
     fun repositoryCount(): SearchResultItemConnectionResponseProjection = repositoryCount(null)
 
     fun repositoryCount(alias: String?): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("repositoryCount").alias(alias))
+        `add$`(GraphQLResponseField("repositoryCount").alias(alias))
         return this
     }
 
     fun userCount(): SearchResultItemConnectionResponseProjection = userCount(null)
 
     fun userCount(alias: String?): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("userCount").alias(alias))
+        `add$`(GraphQLResponseField("userCount").alias(alias))
         return this
     }
 
     fun wikiCount(): SearchResultItemConnectionResponseProjection = wikiCount(null)
 
     fun wikiCount(alias: String?): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("wikiCount").alias(alias))
+        `add$`(GraphQLResponseField("wikiCount").alias(alias))
         return this
     }
 
     fun typename(): SearchResultItemConnectionResponseProjection = typename(null)
 
     fun typename(alias: String?): SearchResultItemConnectionResponseProjection {
-        fields.add(GraphQLResponseField("__typename").alias(alias))
+        `add$`(GraphQLResponseField("__typename").alias(alias))
         return this
     }
 
+    override fun `deepCopy$`(): SearchResultItemConnectionResponseProjection = SearchResultItemConnectionResponseProjection(this)
+
     override fun equals(other: Any?): Boolean {
         if (this === other) {
             return true
@@ -115,4 +123,4 @@ open class SearchResultItemConnectionResponseProjection : GraphQLResponseProject
 
     override fun hashCode(): Int = Objects.hash(fields)
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/kt/SearchResultItemResponseProjection.kt.txt

@@ -11,7 +11,13 @@ import java.util.Objects
     value = ["com.kobylynskyi.graphql.codegen.GraphQLCodegen"],
     date = "2020-12-31T23:59:59-0500"
 )
-open class SearchResultItemResponseProjection : GraphQLResponseProjection() {
+open class SearchResultItemResponseProjection : GraphQLResponseProjection {
+
+    constructor(): super()
+
+    constructor(projection: SearchResultItemResponseProjection): super(projection)
+
+    constructor(projections: List<SearchResultItemResponseProjection>): super(projections)
 
     private val projectionDepthOnFields: MutableMap<String, Int> by lazy { mutableMapOf<String, Int>() }
 
@@ -25,59 +31,61 @@ open class SearchResultItemResponseProjection : GraphQLResponseProjection() {
     fun onApp(subProjection: AppResponseProjection): SearchResultItemResponseProjection = onApp(null, subProjection)
 
     fun onApp(alias: String?, subProjection: AppResponseProjection): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("...on App").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("...on App").alias(alias).projection(subProjection))
         return this
     }
 
     fun onRepository(subProjection: RepositoryResponseProjection): SearchResultItemResponseProjection = onRepository(null, subProjection)
 
     fun onRepository(alias: String?, subProjection: RepositoryResponseProjection): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("...on Repository").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("...on Repository").alias(alias).projection(subProjection))
         return this
     }
 
     fun onIssue(subProjection: IssueResponseProjection): SearchResultItemResponseProjection = onIssue(null, subProjection)
 
     fun onIssue(alias: String?, subProjection: IssueResponseProjection): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("...on Issue").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("...on Issue").alias(alias).projection(subProjection))
         return this
     }
 
     fun onOrganization(subProjection: OrganizationResponseProjection): SearchResultItemResponseProjection = onOrganization(null, subProjection)
 
     fun onOrganization(alias: String?, subProjection: OrganizationResponseProjection): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("...on Organization").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("...on Organization").alias(alias).projection(subProjection))
         return this
     }
 
     fun onUser(subProjection: UserResponseProjection): SearchResultItemResponseProjection = onUser(null, subProjection)
 
     fun onUser(alias: String?, subProjection: UserResponseProjection): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("...on User").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("...on User").alias(alias).projection(subProjection))
         return this
     }
 
     fun onMarketplaceListing(subProjection: MarketplaceListingResponseProjection): SearchResultItemResponseProjection = onMarketplaceListing(null, subProjection)
 
     fun onMarketplaceListing(alias: String?, subProjection: MarketplaceListingResponseProjection): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("...on MarketplaceListing").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("...on MarketplaceListing").alias(alias).projection(subProjection))
         return this
     }
 
     fun onPullRequest(subProjection: PullRequestResponseProjection): SearchResultItemResponseProjection = onPullRequest(null, subProjection)
 
     fun onPullRequest(alias: String?, subProjection: PullRequestResponseProjection): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("...on PullRequest").alias(alias).projection(subProjection))
+        `add$`(GraphQLResponseField("...on PullRequest").alias(alias).projection(subProjection))
         return this
     }
 
     fun typename(): SearchResultItemResponseProjection = typename(null)
 
     fun typename(alias: String?): SearchResultItemResponseProjection {
-        fields.add(GraphQLResponseField("__typename").alias(alias))
+        `add$`(GraphQLResponseField("__typename").alias(alias))
         return this
     }
 
+    override fun `deepCopy$`(): SearchResultItemResponseProjection = SearchResultItemResponseProjection(this)
+
     override fun equals(other: Any?): Boolean {
         if (this === other) {
             return true
@@ -91,4 +99,4 @@ open class SearchResultItemResponseProjection : GraphQLResponseProjection() {
 
     override fun hashCode(): Int = Objects.hash(fields)
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/kt/empty/EventResponseProjection.kt.txt

@@ -8,7 +8,13 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection
     value = ["com.kobylynskyi.graphql.codegen.GraphQLCodegen"],
     date = "2020-12-31T23:59:59-0500"
 )
-open class EventResponseProjection : GraphQLResponseProjection() {
+open class EventResponseProjection : GraphQLResponseProjection {
+
+    constructor(): super()
+
+    constructor(projection: EventResponseProjection): super(projection)
+
+    constructor(projections: List<EventResponseProjection>): super(projections)
 
     private val projectionDepthOnFields: MutableMap<String, Int> by lazy { mutableMapOf<String, Int>() }
 
@@ -22,9 +28,11 @@ open class EventResponseProjection : GraphQLResponseProjection() {
     fun typename(): EventResponseProjection = typename(null)
 
     fun typename(alias: String?): EventResponseProjection {
-        fields.add(GraphQLResponseField("__typename").alias(alias))
+        `add$`(GraphQLResponseField("__typename").alias(alias))
         return this
     }
 
+    override fun `deepCopy$`(): EventResponseProjection = EventResponseProjection(this)
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/kt/restricted-words/CharResponseProjection.kt.txt

@@ -11,7 +11,13 @@ import java.util.Objects
     value = ["com.kobylynskyi.graphql.codegen.GraphQLCodegen"],
     date = "2020-12-31T23:59:59-0500"
 )
-open class CharResponseProjection : GraphQLResponseProjection() {
+open class CharResponseProjection : GraphQLResponseProjection {
+
+    constructor(): super()
+
+    constructor(projection: CharResponseProjection): super(projection)
+
+    constructor(projections: List<CharResponseProjection>): super(projections)
 
     private val projectionDepthOnFields: MutableMap<String, Int> by lazy { mutableMapOf<String, Int>() }
 
@@ -25,10 +31,12 @@ open class CharResponseProjection : GraphQLResponseProjection() {
     fun typename(): CharResponseProjection = typename(null)
 
     fun typename(alias: String?): CharResponseProjection {
-        fields.add(GraphQLResponseField("__typename").alias(alias))
+        `add$`(GraphQLResponseField("__typename").alias(alias))
         return this
     }
 
+    override fun `deepCopy$`(): CharResponseProjection = CharResponseProjection(this)
+
     override fun equals(other: Any?): Boolean {
         if (this === other) {
             return true
@@ -42,4 +50,4 @@ open class CharResponseProjection : GraphQLResponseProjection() {
 
     override fun hashCode(): Int = Objects.hash(fields)
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/kt/restricted-words/QueryFunParametrizedInput.kt.txt

@@ -14,6 +14,13 @@ data class QueryFunParametrizedInput(
     val final: Int?
 ) : GraphQLParametrizedInput {
 
+    override fun deepCopy(): QueryFunParametrizedInput {
+        return QueryFunParametrizedInput(
+            this.final
+        )
+    
+    }
+
     override fun toString(): String {
         val joiner = StringJoiner(", ", "( ", " )")
         if (final != null) {

src/test/resources/expected-classes/kt/restricted-words/QueryPrivateParametrizedInput.kt.txt

@@ -17,6 +17,16 @@ data class QueryPrivateParametrizedInput(
     val createdAfter: java.time.ZonedDateTime?
 ) : GraphQLParametrizedInput {
 
+    override fun deepCopy(): QueryPrivateParametrizedInput {
+        return QueryPrivateParametrizedInput(
+            this.int,
+            this.new,
+            this.enum,
+            this.createdAfter
+        )
+    
+    }
+
     override fun toString(): String {
         val joiner = StringJoiner(", ", "( ", " )")
         if (int != null) {

src/test/resources/expected-classes/projection-with-selectAll/LocationResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Location
@@ -19,6 +20,14 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     public LocationResponseProjection() {
     }
 
+    public LocationResponseProjection(LocationResponseProjection projection) {
+        super(projection);
+    }
+
+    public LocationResponseProjection(List<LocationResponseProjection> projections) {
+        super(projections);
+    }
+
     public LocationResponseProjection all$() {
         return all$(3);
     }
@@ -35,7 +44,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -44,7 +53,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection locationType(String alias) {
-        fields.add(new GraphQLResponseField("locationType").alias(alias));
+        add$(new GraphQLResponseField("locationType").alias(alias));
         return this;
     }
 
@@ -53,7 +62,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection onCustomerLocation(String alias, CustomerLocationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on CustomerLocation").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on CustomerLocation").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -62,7 +71,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection onDealerLocation(String alias, DealerLocationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on DealerLocation").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on DealerLocation").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -71,9 +80,14 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public LocationResponseProjection deepCopy$() {
+        return new LocationResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/projection-with-selectAll/VehicleResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Vehicle
@@ -19,6 +20,14 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     public VehicleResponseProjection() {
     }
 
+    public VehicleResponseProjection(VehicleResponseProjection projection) {
+        super(projection);
+    }
+
+    public VehicleResponseProjection(List<VehicleResponseProjection> projections) {
+        super(projections);
+    }
+
     public VehicleResponseProjection all$() {
         return all$(3);
     }
@@ -39,7 +48,7 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection vehicleId(String alias) {
-        fields.add(new GraphQLResponseField("vehicleId").alias(alias));
+        add$(new GraphQLResponseField("vehicleId").alias(alias));
         return this;
     }
 
@@ -48,7 +57,7 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection registrationNumber(String alias) {
-        fields.add(new GraphQLResponseField("registrationNumber").alias(alias));
+        add$(new GraphQLResponseField("registrationNumber").alias(alias));
         return this;
     }
 
@@ -57,7 +66,7 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection location(String alias, LocationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("location").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("location").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -66,9 +75,14 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public VehicleResponseProjection deepCopy$() {
+        return new VehicleResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/ClientDataParametrizedInput.java.txt

@@ -28,6 +28,13 @@ public class ClientDataParametrizedInput implements GraphQLParametrizedInput {
         return this;
     }
 
+    @Override
+    public ClientDataParametrizedInput deepCopy() {
+        ClientDataParametrizedInput parametrizedInput = new ClientDataParametrizedInput();
+        parametrizedInput.ID(this.ID);
+        return parametrizedInput;
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -52,4 +59,4 @@ public class ClientDataParametrizedInput implements GraphQLParametrizedInput {
         return joiner.toString();
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/CodeOfConductResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -20,6 +21,14 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     public CodeOfConductResponseProjection() {
     }
 
+    public CodeOfConductResponseProjection(CodeOfConductResponseProjection projection) {
+        super(projection);
+    }
+
+    public CodeOfConductResponseProjection(List<CodeOfConductResponseProjection> projections) {
+        super(projections);
+    }
+
     public CodeOfConductResponseProjection all$() {
         return all$(3);
     }
@@ -40,7 +49,7 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     }
 
     public CodeOfConductResponseProjection body(String alias) {
-        fields.add(new GraphQLResponseField("body").alias(alias));
+        add$(new GraphQLResponseField("body").alias(alias));
         return this;
     }
 
@@ -49,7 +58,7 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     }
 
     public CodeOfConductResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -58,7 +67,7 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     }
 
     public CodeOfConductResponseProjection key(String alias) {
-        fields.add(new GraphQLResponseField("key").alias(alias));
+        add$(new GraphQLResponseField("key").alias(alias));
         return this;
     }
 
@@ -67,7 +76,7 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     }
 
     public CodeOfConductResponseProjection name(String alias) {
-        fields.add(new GraphQLResponseField("name").alias(alias));
+        add$(new GraphQLResponseField("name").alias(alias));
         return this;
     }
 
@@ -76,7 +85,7 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     }
 
     public CodeOfConductResponseProjection resourcePath(String alias) {
-        fields.add(new GraphQLResponseField("resourcePath").alias(alias));
+        add$(new GraphQLResponseField("resourcePath").alias(alias));
         return this;
     }
 
@@ -85,7 +94,7 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     }
 
     public CodeOfConductResponseProjection url(String alias) {
-        fields.add(new GraphQLResponseField("url").alias(alias));
+        add$(new GraphQLResponseField("url").alias(alias));
         return this;
     }
 
@@ -94,10 +103,15 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
     }
 
     public CodeOfConductResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public CodeOfConductResponseProjection deepCopy$() {
+        return new CodeOfConductResponseProjection(this);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -115,4 +129,4 @@ public class CodeOfConductResponseProjection extends GraphQLResponseProjection {
         return Objects.hash(fields);
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/EventPropertyChildParametrizedInput.java.txt

@@ -35,6 +35,14 @@ public class EventPropertyChildParametrizedInput implements GraphQLParametrizedI
         return this;
     }
 
+    @Override
+    public EventPropertyChildParametrizedInput deepCopy() {
+        EventPropertyChildParametrizedInput parametrizedInput = new EventPropertyChildParametrizedInput();
+        parametrizedInput.first(this.first);
+        parametrizedInput.last(this.last);
+        return parametrizedInput;
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {

src/test/resources/expected-classes/request/EventPropertyChildParametrizedInput_withoutPrimitives.java.txt

@@ -35,6 +35,14 @@ public class EventPropertyChildParametrizedInput implements GraphQLParametrizedI
         return this;
     }
 
+    @Override
+    public EventPropertyChildParametrizedInput deepCopy() {
+        EventPropertyChildParametrizedInput parametrizedInput = new EventPropertyChildParametrizedInput();
+        parametrizedInput.first(this.first);
+        parametrizedInput.last(this.last);
+        return parametrizedInput;
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {

src/test/resources/expected-classes/request/EventPropertyParentParametrizedInput.java.txt

@@ -35,6 +35,14 @@ public class EventPropertyParentParametrizedInput implements GraphQLParametrized
         return this;
     }
 
+    @Override
+    public EventPropertyParentParametrizedInput deepCopy() {
+        EventPropertyParentParametrizedInput parametrizedInput = new EventPropertyParentParametrizedInput();
+        parametrizedInput.withStatus(this.withStatus);
+        parametrizedInput.createdAfter(this.createdAfter);
+        return parametrizedInput;
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -65,4 +73,4 @@ public class EventPropertyParentParametrizedInput implements GraphQLParametrized
         return joiner.toString();
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/EventPropertyParentParametrizedInput_withModelSuffix.java.txt

@@ -35,6 +35,14 @@ public class EventPropertyParentParametrizedInput implements GraphQLParametrized
         return this;
     }
 
+    @Override
+    public EventPropertyParentParametrizedInput deepCopy() {
+        EventPropertyParentParametrizedInput parametrizedInput = new EventPropertyParentParametrizedInput();
+        parametrizedInput.withStatus(this.withStatus);
+        parametrizedInput.createdAfter(this.createdAfter);
+        return parametrizedInput;
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -65,4 +73,4 @@ public class EventPropertyParentParametrizedInput implements GraphQLParametrized
         return joiner.toString();
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/EventPropertyResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -20,6 +21,14 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     public EventPropertyResponseProjection() {
     }
 
+    public EventPropertyResponseProjection(EventPropertyResponseProjection projection) {
+        super(projection);
+    }
+
+    public EventPropertyResponseProjection(List<EventPropertyResponseProjection> projections) {
+        super(projections);
+    }
+
     public EventPropertyResponseProjection all$() {
         return all$(3);
     }
@@ -47,7 +56,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection floatVal(String alias) {
-        fields.add(new GraphQLResponseField("floatVal").alias(alias));
+        add$(new GraphQLResponseField("floatVal").alias(alias));
         return this;
     }
 
@@ -56,7 +65,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection booleanVal(String alias) {
-        fields.add(new GraphQLResponseField("booleanVal").alias(alias));
+        add$(new GraphQLResponseField("booleanVal").alias(alias));
         return this;
     }
 
@@ -65,7 +74,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection intVal(String alias) {
-        fields.add(new GraphQLResponseField("intVal").alias(alias));
+        add$(new GraphQLResponseField("intVal").alias(alias));
         return this;
     }
 
@@ -74,7 +83,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection intVals(String alias) {
-        fields.add(new GraphQLResponseField("intVals").alias(alias));
+        add$(new GraphQLResponseField("intVals").alias(alias));
         return this;
     }
 
@@ -83,7 +92,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection stringVal(String alias) {
-        fields.add(new GraphQLResponseField("stringVal").alias(alias));
+        add$(new GraphQLResponseField("stringVal").alias(alias));
         return this;
     }
 
@@ -92,7 +101,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection child(String alias, EventPropertyResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("child").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("child").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -101,7 +110,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection child(String alias, EventPropertyChildParametrizedInput input, EventPropertyResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("child").alias(alias).parameters(input).projection(subProjection));
+        add$(new GraphQLResponseField("child").alias(alias).parameters(input).projection(subProjection));
         return this;
     }
 
@@ -110,7 +119,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection parent(String alias, EventResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("parent").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("parent").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -119,7 +128,7 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection parent(String alias, EventPropertyParentParametrizedInput input, EventResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("parent").alias(alias).parameters(input).projection(subProjection));
+        add$(new GraphQLResponseField("parent").alias(alias).parameters(input).projection(subProjection));
         return this;
     }
 
@@ -128,10 +137,15 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventPropertyResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public EventPropertyResponseProjection deepCopy$() {
+        return new EventPropertyResponseProjection(this);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -149,4 +163,4 @@ public class EventPropertyResponseProjection extends GraphQLResponseProjection {
         return Objects.hash(fields);
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/EventResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -20,6 +21,14 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     public EventResponseProjection() {
     }
 
+    public EventResponseProjection(EventResponseProjection projection) {
+        super(projection);
+    }
+
+    public EventResponseProjection(List<EventResponseProjection> projections) {
+        super(projections);
+    }
+
     public EventResponseProjection all$() {
         return all$(3);
     }
@@ -45,7 +54,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -54,7 +63,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection categoryId(String alias) {
-        fields.add(new GraphQLResponseField("categoryId").alias(alias));
+        add$(new GraphQLResponseField("categoryId").alias(alias));
         return this;
     }
 
@@ -63,7 +72,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection properties(String alias, EventPropertyResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("properties").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("properties").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -72,7 +81,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection status(String alias) {
-        fields.add(new GraphQLResponseField("status").alias(alias));
+        add$(new GraphQLResponseField("status").alias(alias));
         return this;
     }
 
@@ -81,7 +90,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdBy(String alias) {
-        fields.add(new GraphQLResponseField("createdBy").alias(alias));
+        add$(new GraphQLResponseField("createdBy").alias(alias));
         return this;
     }
 
@@ -90,7 +99,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdDateTime(String alias) {
-        fields.add(new GraphQLResponseField("createdDateTime").alias(alias));
+        add$(new GraphQLResponseField("createdDateTime").alias(alias));
         return this;
     }
 
@@ -99,7 +108,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection active(String alias) {
-        fields.add(new GraphQLResponseField("active").alias(alias));
+        add$(new GraphQLResponseField("active").alias(alias));
         return this;
     }
 
@@ -108,7 +117,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection rating(String alias) {
-        fields.add(new GraphQLResponseField("rating").alias(alias));
+        add$(new GraphQLResponseField("rating").alias(alias));
         return this;
     }
 
@@ -117,10 +126,15 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public EventResponseProjection deepCopy$() {
+        return new EventResponseProjection(this);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -138,4 +152,4 @@ public class EventResponseProjection extends GraphQLResponseProjection {
         return Objects.hash(fields);
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/EventResponseProjection.java_withoutAll.txt

@@ -2,6 +2,7 @@ package com.github.graphql;
 
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -16,12 +17,20 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     public EventResponseProjection() {
     }
 
+    public EventResponseProjection(EventResponseProjection projection) {
+        super(projection);
+    }
+
+    public EventResponseProjection(List<EventResponseProjection> projections) {
+        super(projections);
+    }
+
     public EventResponseProjection id() {
         return id(null);
     }
 
     public EventResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -30,7 +39,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection categoryId(String alias) {
-        fields.add(new GraphQLResponseField("categoryId").alias(alias));
+        add$(new GraphQLResponseField("categoryId").alias(alias));
         return this;
     }
 
@@ -39,7 +48,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection properties(String alias, EventPropertyResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("properties").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("properties").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -48,7 +57,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection status(String alias) {
-        fields.add(new GraphQLResponseField("status").alias(alias));
+        add$(new GraphQLResponseField("status").alias(alias));
         return this;
     }
 
@@ -57,7 +66,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdBy(String alias) {
-        fields.add(new GraphQLResponseField("createdBy").alias(alias));
+        add$(new GraphQLResponseField("createdBy").alias(alias));
         return this;
     }
 
@@ -66,7 +75,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection createdDateTime(String alias) {
-        fields.add(new GraphQLResponseField("createdDateTime").alias(alias));
+        add$(new GraphQLResponseField("createdDateTime").alias(alias));
         return this;
     }
 
@@ -75,7 +84,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection active(String alias) {
-        fields.add(new GraphQLResponseField("active").alias(alias));
+        add$(new GraphQLResponseField("active").alias(alias));
         return this;
     }
 
@@ -84,7 +93,7 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection rating(String alias) {
-        fields.add(new GraphQLResponseField("rating").alias(alias));
+        add$(new GraphQLResponseField("rating").alias(alias));
         return this;
     }
 
@@ -93,10 +102,15 @@ public class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     public EventResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public EventResponseProjection deepCopy$() {
+        return new EventResponseProjection(this);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -114,4 +128,4 @@ public class EventResponseProjection extends GraphQLResponseProjection {
         return Objects.hash(fields);
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/request/ProductLinkCodeParametrizedInput.java.txt

@@ -28,6 +28,13 @@ public class ProductLinkCodeParametrizedInput implements GraphQLParametrizedInpu
         return this;
     }
 
+    @Override
+    public ProductLinkCodeParametrizedInput deepCopy() {
+        ProductLinkCodeParametrizedInput parametrizedInput = new ProductLinkCodeParametrizedInput();
+        parametrizedInput.pid(this.pid);
+        return parametrizedInput;
+    }
+
 
     @Override
     public String toString() {

src/test/resources/expected-classes/response/LocationResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Location
@@ -19,6 +20,14 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     public LocationResponseProjection() {
     }
 
+    public LocationResponseProjection(LocationResponseProjection projection) {
+        super(projection);
+    }
+
+    public LocationResponseProjection(List<LocationResponseProjection> projections) {
+        super(projections);
+    }
+
     public LocationResponseProjection all$() {
         return all$(3);
     }
@@ -35,7 +44,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection id(String alias) {
-        fields.add(new GraphQLResponseField("id").alias(alias));
+        add$(new GraphQLResponseField("id").alias(alias));
         return this;
     }
 
@@ -44,7 +53,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection locationType(String alias) {
-        fields.add(new GraphQLResponseField("locationType").alias(alias));
+        add$(new GraphQLResponseField("locationType").alias(alias));
         return this;
     }
 
@@ -53,7 +62,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection onCustomerLocation(String alias, CustomerLocationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on CustomerLocation").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on CustomerLocation").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -62,7 +71,7 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection onDealerLocation(String alias, DealerLocationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on DealerLocation").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on DealerLocation").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -71,9 +80,14 @@ public class LocationResponseProjection extends GraphQLResponseProjection {
     }
 
     public LocationResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public LocationResponseProjection deepCopy$() {
+        return new LocationResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/response/SearchResultItemConnectionResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for SearchResultItemConnection
@@ -19,6 +20,14 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     public SearchResultItemConnectionResponseProjection() {
     }
 
+    public SearchResultItemConnectionResponseProjection(SearchResultItemConnectionResponseProjection projection) {
+        super(projection);
+    }
+
+    public SearchResultItemConnectionResponseProjection(List<SearchResultItemConnectionResponseProjection> projections) {
+        super(projections);
+    }
+
     public SearchResultItemConnectionResponseProjection all$() {
         return all$(3);
     }
@@ -50,7 +59,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection codeCount(String alias) {
-        fields.add(new GraphQLResponseField("codeCount").alias(alias));
+        add$(new GraphQLResponseField("codeCount").alias(alias));
         return this;
     }
 
@@ -59,7 +68,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection edges(String alias, SearchResultItemEdgeResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("edges").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("edges").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -68,7 +77,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection issueCount(String alias) {
-        fields.add(new GraphQLResponseField("issueCount").alias(alias));
+        add$(new GraphQLResponseField("issueCount").alias(alias));
         return this;
     }
 
@@ -77,7 +86,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection nodes(String alias, SearchResultItemResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("nodes").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("nodes").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -86,7 +95,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection pageInfo(String alias, PageInfoResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("pageInfo").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("pageInfo").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -95,7 +104,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection repositoryCount(String alias) {
-        fields.add(new GraphQLResponseField("repositoryCount").alias(alias));
+        add$(new GraphQLResponseField("repositoryCount").alias(alias));
         return this;
     }
 
@@ -104,7 +113,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection userCount(String alias) {
-        fields.add(new GraphQLResponseField("userCount").alias(alias));
+        add$(new GraphQLResponseField("userCount").alias(alias));
         return this;
     }
 
@@ -113,7 +122,7 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection wikiCount(String alias) {
-        fields.add(new GraphQLResponseField("wikiCount").alias(alias));
+        add$(new GraphQLResponseField("wikiCount").alias(alias));
         return this;
     }
 
@@ -122,9 +131,14 @@ public class SearchResultItemConnectionResponseProjection extends GraphQLRespons
     }
 
     public SearchResultItemConnectionResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public SearchResultItemConnectionResponseProjection deepCopy$() {
+        return new SearchResultItemConnectionResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/response/SearchResultItemResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for SearchResultItem
@@ -19,6 +20,14 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     public SearchResultItemResponseProjection() {
     }
 
+    public SearchResultItemResponseProjection(SearchResultItemResponseProjection projection) {
+        super(projection);
+    }
+
+    public SearchResultItemResponseProjection(List<SearchResultItemResponseProjection> projections) {
+        super(projections);
+    }
+
     public SearchResultItemResponseProjection all$() {
         return all$(3);
     }
@@ -33,7 +42,7 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection onApp(String alias, AppResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on App").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on App").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -42,7 +51,7 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection onRepository(String alias, RepositoryResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on Repository").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on Repository").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -51,7 +60,7 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection onIssue(String alias, IssueResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on Issue").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on Issue").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -60,7 +69,7 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection onOrganization(String alias, OrganizationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on Organization").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on Organization").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -69,7 +78,7 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection onUser(String alias, UserResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on User").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on User").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -78,7 +87,7 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection onMarketplaceListing(String alias, MarketplaceListingResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on MarketplaceListing").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on MarketplaceListing").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -87,7 +96,7 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection onPullRequest(String alias, PullRequestResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("...on PullRequest").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("...on PullRequest").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -96,9 +105,14 @@ public class SearchResultItemResponseProjection extends GraphQLResponseProjectio
     }
 
     public SearchResultItemResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public SearchResultItemResponseProjection deepCopy$() {
+        return new SearchResultItemResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/response/VehicleResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 
 /**
  * Response projection for Vehicle
@@ -19,6 +20,14 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     public VehicleResponseProjection() {
     }
 
+    public VehicleResponseProjection(VehicleResponseProjection projection) {
+        super(projection);
+    }
+
+    public VehicleResponseProjection(List<VehicleResponseProjection> projections) {
+        super(projections);
+    }
+
     public VehicleResponseProjection all$() {
         return all$(3);
     }
@@ -39,7 +48,7 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection vehicleId(String alias) {
-        fields.add(new GraphQLResponseField("vehicleId").alias(alias));
+        add$(new GraphQLResponseField("vehicleId").alias(alias));
         return this;
     }
 
@@ -48,7 +57,7 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection registrationNumber(String alias) {
-        fields.add(new GraphQLResponseField("registrationNumber").alias(alias));
+        add$(new GraphQLResponseField("registrationNumber").alias(alias));
         return this;
     }
 
@@ -57,7 +66,7 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection location(String alias, LocationResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("location").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("location").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -66,9 +75,14 @@ public class VehicleResponseProjection extends GraphQLResponseProjection {
     }
 
     public VehicleResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public VehicleResponseProjection deepCopy$() {
+        return new VehicleResponseProjection(this);
+    }
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/restricted-words/CharResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -20,6 +21,14 @@ public class CharResponseProjection extends GraphQLResponseProjection {
     public CharResponseProjection() {
     }
 
+    public CharResponseProjection(CharResponseProjection projection) {
+        super(projection);
+    }
+
+    public CharResponseProjection(List<CharResponseProjection> projections) {
+        super(projections);
+    }
+
     public CharResponseProjection all$() {
         return all$(3);
     }
@@ -34,10 +43,15 @@ public class CharResponseProjection extends GraphQLResponseProjection {
     }
 
     public CharResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public CharResponseProjection deepCopy$() {
+        return new CharResponseProjection(this);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -55,4 +69,4 @@ public class CharResponseProjection extends GraphQLResponseProjection {
         return Objects.hash(fields);
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/restricted-words/QueryCaseParametrizedInput.java.txt

@@ -28,6 +28,13 @@ public class QueryCaseParametrizedInput implements GraphQLParametrizedInput {
         return this;
     }
 
+    @Override
+    public QueryCaseParametrizedInput deepCopy() {
+        QueryCaseParametrizedInput parametrizedInput = new QueryCaseParametrizedInput();
+        parametrizedInput.Final(this.Final);
+        return parametrizedInput;
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -54,4 +61,4 @@ public class QueryCaseParametrizedInput implements GraphQLParametrizedInput {
         return joiner.toString();
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/restricted-words/QueryPrivateParametrizedInput.java.txt

@@ -42,6 +42,15 @@ public class QueryPrivateParametrizedInput implements GraphQLParametrizedInput {
         return this;
     }
 
+    @Override
+    public QueryPrivateParametrizedInput deepCopy() {
+        QueryPrivateParametrizedInput parametrizedInput = new QueryPrivateParametrizedInput();
+        parametrizedInput.Int(this.Int);
+        parametrizedInput.New(this.New);
+        parametrizedInput.Enum(this.Enum);
+        return parametrizedInput;
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {

src/test/resources/expected-classes/restricted-words/QueryResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -20,6 +21,14 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
     public QueryResponseProjection() {
     }
 
+    public QueryResponseProjection(QueryResponseProjection projection) {
+        super(projection);
+    }
+
+    public QueryResponseProjection(List<QueryResponseProjection> projections) {
+        super(projections);
+    }
+
     public QueryResponseProjection all$() {
         return all$(3);
     }
@@ -40,7 +49,7 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
     }
 
     public QueryResponseProjection Native(String alias) {
-        fields.add(new GraphQLResponseField("native").alias(alias));
+        add$(new GraphQLResponseField("native").alias(alias));
         return this;
     }
 
@@ -49,7 +58,7 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
     }
 
     public QueryResponseProjection Private(String alias, SynchronizedResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("private").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("private").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -58,7 +67,7 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
     }
 
     public QueryResponseProjection Private(String alias, QueryPrivateParametrizedInput input, SynchronizedResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("private").alias(alias).parameters(input).projection(subProjection));
+        add$(new GraphQLResponseField("private").alias(alias).parameters(input).projection(subProjection));
         return this;
     }
 
@@ -67,7 +76,7 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
     }
 
     public QueryResponseProjection Case(String alias) {
-        fields.add(new GraphQLResponseField("case").alias(alias));
+        add$(new GraphQLResponseField("case").alias(alias));
         return this;
     }
 
@@ -76,7 +85,7 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
     }
 
     public QueryResponseProjection Case(String alias, QueryCaseParametrizedInput input) {
-        fields.add(new GraphQLResponseField("case").alias(alias).parameters(input));
+        add$(new GraphQLResponseField("case").alias(alias).parameters(input));
         return this;
     }
 
@@ -85,10 +94,15 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
     }
 
     public QueryResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public QueryResponseProjection deepCopy$() {
+        return new QueryResponseProjection(this);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {
@@ -106,4 +120,4 @@ public class QueryResponseProjection extends GraphQLResponseProjection {
         return Objects.hash(fields);
     }
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/restricted-words/SynchronizedResponseProjection.java.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField;
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -20,6 +21,14 @@ public class SynchronizedResponseProjection extends GraphQLResponseProjection {
     public SynchronizedResponseProjection() {
     }
 
+    public SynchronizedResponseProjection(SynchronizedResponseProjection projection) {
+        super(projection);
+    }
+
+    public SynchronizedResponseProjection(List<SynchronizedResponseProjection> projections) {
+        super(projections);
+    }
+
     public SynchronizedResponseProjection all$() {
         return all$(3);
     }
@@ -40,7 +49,7 @@ public class SynchronizedResponseProjection extends GraphQLResponseProjection {
     }
 
     public SynchronizedResponseProjection Void(String alias) {
-        fields.add(new GraphQLResponseField("void").alias(alias));
+        add$(new GraphQLResponseField("void").alias(alias));
         return this;
     }
 
@@ -49,7 +58,7 @@ public class SynchronizedResponseProjection extends GraphQLResponseProjection {
     }
 
     public SynchronizedResponseProjection Wait(String alias, CharResponseProjection subProjection) {
-        fields.add(new GraphQLResponseField("wait").alias(alias).projection(subProjection));
+        add$(new GraphQLResponseField("wait").alias(alias).projection(subProjection));
         return this;
     }
 
@@ -58,7 +67,7 @@ public class SynchronizedResponseProjection extends GraphQLResponseProjection {
     }
 
     public SynchronizedResponseProjection Class(String alias) {
-        fields.add(new GraphQLResponseField("class").alias(alias));
+        add$(new GraphQLResponseField("class").alias(alias));
         return this;
     }
 
@@ -67,10 +76,15 @@ public class SynchronizedResponseProjection extends GraphQLResponseProjection {
     }
 
     public SynchronizedResponseProjection typename(String alias) {
-        fields.add(new GraphQLResponseField("__typename").alias(alias));
+        add$(new GraphQLResponseField("__typename").alias(alias));
         return this;
     }
 
+    @Override
+    public SynchronizedResponseProjection deepCopy$() {
+        return new SynchronizedResponseProjection(this);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) {

src/test/resources/expected-classes/scala/SearchResultItemConnectionResponseProjection.scala.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection
 import java.util.Objects
 import scala.collection.mutable.HashMap
+import scala.collection.JavaConverters._
 
 /**
  * Response projection for SearchResultItemConnection
@@ -12,7 +13,29 @@ import scala.collection.mutable.HashMap
     value = Array("com.kobylynskyi.graphql.codegen.GraphQLCodegen"),
     date = "2020-12-31T23:59:59-0500"
 )
-class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjection {
+class SearchResultItemConnectionResponseProjection() extends GraphQLResponseProjection() {
+
+    def this(projection: SearchResultItemConnectionResponseProjection) = {
+        this()
+        if (projection != null) {
+            for (field <- projection.fields.values.asScala) {
+                add$(field)
+            }
+        }
+    }
+
+    def this(projections: scala.Seq[SearchResultItemConnectionResponseProjection]) = {
+        this()
+        if (projections != null) {
+            for (projection <- projections) {
+                if (projection != null) {
+                    for (field <- projection.fields.values.asScala) {
+                        add$(field)
+                    }
+                }
+            }
+        }
+    }
 
     private final lazy val projectionDepthOnFields = new HashMap[String, Int]
 
@@ -45,7 +68,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def codeCount(alias: String): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("codeCount").alias(alias))
+        add$(new GraphQLResponseField("codeCount").alias(alias))
         this
     }
 
@@ -54,7 +77,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def edges(alias: String, subProjection: SearchResultItemEdgeResponseProjection): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("edges").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("edges").alias(alias).projection(subProjection))
         this
     }
 
@@ -63,7 +86,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def issueCount(alias: String): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("issueCount").alias(alias))
+        add$(new GraphQLResponseField("issueCount").alias(alias))
         this
     }
 
@@ -72,7 +95,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def nodes(alias: String, subProjection: SearchResultItemResponseProjection): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("nodes").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("nodes").alias(alias).projection(subProjection))
         this
     }
 
@@ -81,7 +104,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def pageInfo(alias: String, subProjection: PageInfoResponseProjection): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("pageInfo").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("pageInfo").alias(alias).projection(subProjection))
         this
     }
 
@@ -90,7 +113,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def repositoryCount(alias: String): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("repositoryCount").alias(alias))
+        add$(new GraphQLResponseField("repositoryCount").alias(alias))
         this
     }
 
@@ -99,7 +122,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def userCount(alias: String): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("userCount").alias(alias))
+        add$(new GraphQLResponseField("userCount").alias(alias))
         this
     }
 
@@ -108,7 +131,7 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def wikiCount(alias: String): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("wikiCount").alias(alias))
+        add$(new GraphQLResponseField("wikiCount").alias(alias))
         this
     }
 
@@ -117,10 +140,12 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
     }
 
     def typename(alias: String): SearchResultItemConnectionResponseProjection = {
-        fields.add(new GraphQLResponseField("__typename").alias(alias))
+        add$(new GraphQLResponseField("__typename").alias(alias))
         this
     }
 
+    override def deepCopy$(): SearchResultItemConnectionResponseProjection = new SearchResultItemConnectionResponseProjection(this)
+
     override def equals(obj: Any): Boolean = {
         if (this == obj) {
             return true
@@ -134,4 +159,4 @@ class SearchResultItemConnectionResponseProjection extends GraphQLResponseProjec
 
     override def hashCode(): Int = Objects.hash(fields)
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/scala/SearchResultItemResponseProjection.scala.txt

@@ -4,6 +4,7 @@ import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection
 import java.util.Objects
 import scala.collection.mutable.HashMap
+import scala.collection.JavaConverters._
 
 /**
  * Response projection for SearchResultItem
@@ -12,7 +13,29 @@ import scala.collection.mutable.HashMap
     value = Array("com.kobylynskyi.graphql.codegen.GraphQLCodegen"),
     date = "2020-12-31T23:59:59-0500"
 )
-class SearchResultItemResponseProjection extends GraphQLResponseProjection {
+class SearchResultItemResponseProjection() extends GraphQLResponseProjection() {
+
+    def this(projection: SearchResultItemResponseProjection) = {
+        this()
+        if (projection != null) {
+            for (field <- projection.fields.values.asScala) {
+                add$(field)
+            }
+        }
+    }
+
+    def this(projections: scala.Seq[SearchResultItemResponseProjection]) = {
+        this()
+        if (projections != null) {
+            for (projection <- projections) {
+                if (projection != null) {
+                    for (field <- projection.fields.values.asScala) {
+                        add$(field)
+                    }
+                }
+            }
+        }
+    }
 
     private final lazy val projectionDepthOnFields = new HashMap[String, Int]
 
@@ -28,7 +51,7 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def onApp(alias: String, subProjection: AppResponseProjection): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("...on App").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("...on App").alias(alias).projection(subProjection))
         this
     }
 
@@ -37,7 +60,7 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def onRepository(alias: String, subProjection: RepositoryResponseProjection): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("...on Repository").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("...on Repository").alias(alias).projection(subProjection))
         this
     }
 
@@ -46,7 +69,7 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def onIssue(alias: String, subProjection: IssueResponseProjection): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("...on Issue").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("...on Issue").alias(alias).projection(subProjection))
         this
     }
 
@@ -55,7 +78,7 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def onOrganization(alias: String, subProjection: OrganizationResponseProjection): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("...on Organization").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("...on Organization").alias(alias).projection(subProjection))
         this
     }
 
@@ -64,7 +87,7 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def onUser(alias: String, subProjection: UserResponseProjection): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("...on User").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("...on User").alias(alias).projection(subProjection))
         this
     }
 
@@ -73,7 +96,7 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def onMarketplaceListing(alias: String, subProjection: MarketplaceListingResponseProjection): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("...on MarketplaceListing").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("...on MarketplaceListing").alias(alias).projection(subProjection))
         this
     }
 
@@ -82,7 +105,7 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def onPullRequest(alias: String, subProjection: PullRequestResponseProjection): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("...on PullRequest").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("...on PullRequest").alias(alias).projection(subProjection))
         this
     }
 
@@ -91,10 +114,12 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
     }
 
     def typename(alias: String): SearchResultItemResponseProjection = {
-        fields.add(new GraphQLResponseField("__typename").alias(alias))
+        add$(new GraphQLResponseField("__typename").alias(alias))
         this
     }
 
+    override def deepCopy$(): SearchResultItemResponseProjection = new SearchResultItemResponseProjection(this)
+
     override def equals(obj: Any): Boolean = {
         if (this == obj) {
             return true
@@ -108,4 +133,4 @@ class SearchResultItemResponseProjection extends GraphQLResponseProjection {
 
     override def hashCode(): Int = Objects.hash(fields)
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/scala/empty/EventResponseProjection.scala.txt

 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection
 import scala.collection.mutable.HashMap
+import scala.collection.JavaConverters._
 
 /**
  * Response projection for Event
@@ -9,7 +10,29 @@ import scala.collection.mutable.HashMap
     value = Array("com.kobylynskyi.graphql.codegen.GraphQLCodegen"),
     date = "2020-12-31T23:59:59-0500"
 )
-class EventResponseProjection extends GraphQLResponseProjection {
+class EventResponseProjection() extends GraphQLResponseProjection() {
+
+    def this(projection: EventResponseProjection) = {
+        this()
+        if (projection != null) {
+            for (field <- projection.fields.values.asScala) {
+                add$(field)
+            }
+        }
+    }
+
+    def this(projections: scala.Seq[EventResponseProjection]) = {
+        this()
+        if (projections != null) {
+            for (projection <- projections) {
+                if (projection != null) {
+                    for (field <- projection.fields.values.asScala) {
+                        add$(field)
+                    }
+                }
+            }
+        }
+    }
 
     private final lazy val projectionDepthOnFields = new HashMap[String, Int]
 
@@ -25,9 +48,11 @@ class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     def typename(alias: String): EventResponseProjection = {
-        fields.add(new GraphQLResponseField("__typename").alias(alias))
+        add$(new GraphQLResponseField("__typename").alias(alias))
         this
     }
 
+    override def deepCopy$(): EventResponseProjection = new EventResponseProjection(this)
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/scala/extend/request/AssetResponseProjection.scala.txt

 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection
 import scala.collection.mutable.HashMap
+import scala.collection.JavaConverters._
 
 /**
  * Response projection for Asset
@@ -9,7 +10,29 @@ import scala.collection.mutable.HashMap
     value = Array("com.kobylynskyi.graphql.codegen.GraphQLCodegen"),
     date = "2020-12-31T23:59:59-0500"
 )
-class AssetResponseProjection extends GraphQLResponseProjection {
+class AssetResponseProjection() extends GraphQLResponseProjection() {
+
+    def this(projection: AssetResponseProjection) = {
+        this()
+        if (projection != null) {
+            for (field <- projection.fields.values.asScala) {
+                add$(field)
+            }
+        }
+    }
+
+    def this(projections: scala.Seq[AssetResponseProjection]) = {
+        this()
+        if (projections != null) {
+            for (projection <- projections) {
+                if (projection != null) {
+                    for (field <- projection.fields.values.asScala) {
+                        add$(field)
+                    }
+                }
+            }
+        }
+    }
 
     private final lazy val projectionDepthOnFields = new HashMap[String, Int]
 
@@ -29,7 +52,7 @@ class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     def name(alias: String): AssetResponseProjection = {
-        fields.add(new GraphQLResponseField("name").alias(alias))
+        add$(new GraphQLResponseField("name").alias(alias))
         this
     }
 
@@ -38,7 +61,7 @@ class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     def status(alias: String): AssetResponseProjection = {
-        fields.add(new GraphQLResponseField("status").alias(alias))
+        add$(new GraphQLResponseField("status").alias(alias))
         this
     }
 
@@ -47,7 +70,7 @@ class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     def id(alias: String): AssetResponseProjection = {
-        fields.add(new GraphQLResponseField("id").alias(alias))
+        add$(new GraphQLResponseField("id").alias(alias))
         this
     }
 
@@ -56,7 +79,7 @@ class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     def createdBy(alias: String): AssetResponseProjection = {
-        fields.add(new GraphQLResponseField("createdBy").alias(alias))
+        add$(new GraphQLResponseField("createdBy").alias(alias))
         this
     }
 
@@ -65,9 +88,11 @@ class AssetResponseProjection extends GraphQLResponseProjection {
     }
 
     def typename(alias: String): AssetResponseProjection = {
-        fields.add(new GraphQLResponseField("__typename").alias(alias))
+        add$(new GraphQLResponseField("__typename").alias(alias))
         this
     }
 
+    override def deepCopy$(): AssetResponseProjection = new AssetResponseProjection(this)
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/scala/extend/request/EventResponseProjection.scala.txt

 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseField
 import com.kobylynskyi.graphql.codegen.model.graphql.GraphQLResponseProjection
 import scala.collection.mutable.HashMap
+import scala.collection.JavaConverters._
 
 /**
  * Response projection for Event
@@ -9,7 +10,29 @@ import scala.collection.mutable.HashMap
     value = Array("com.kobylynskyi.graphql.codegen.GraphQLCodegen"),
     date = "2020-12-31T23:59:59-0500"
 )
-class EventResponseProjection extends GraphQLResponseProjection {
+class EventResponseProjection() extends GraphQLResponseProjection() {
+
+    def this(projection: EventResponseProjection) = {
+        this()
+        if (projection != null) {
+            for (field <- projection.fields.values.asScala) {
+                add$(field)
+            }
+        }
+    }
+
+    def this(projections: scala.Seq[EventResponseProjection]) = {
+        this()
+        if (projections != null) {
+            for (projection <- projections) {
+                if (projection != null) {
+                    for (field <- projection.fields.values.asScala) {
+                        add$(field)
+                    }
+                }
+            }
+        }
+    }
 
     private final lazy val projectionDepthOnFields = new HashMap[String, Int]
 
@@ -33,7 +56,7 @@ class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     def status(alias: String): EventResponseProjection = {
-        fields.add(new GraphQLResponseField("status").alias(alias))
+        add$(new GraphQLResponseField("status").alias(alias))
         this
     }
 
@@ -42,7 +65,7 @@ class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     def createdDateTime(alias: String): EventResponseProjection = {
-        fields.add(new GraphQLResponseField("createdDateTime").alias(alias))
+        add$(new GraphQLResponseField("createdDateTime").alias(alias))
         this
     }
 
@@ -51,7 +74,7 @@ class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     def assets(alias: String, subProjection: AssetResponseProjection): EventResponseProjection = {
-        fields.add(new GraphQLResponseField("assets").alias(alias).projection(subProjection))
+        add$(new GraphQLResponseField("assets").alias(alias).projection(subProjection))
         this
     }
 
@@ -60,7 +83,7 @@ class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     def id(alias: String): EventResponseProjection = {
-        fields.add(new GraphQLResponseField("id").alias(alias))
+        add$(new GraphQLResponseField("id").alias(alias))
         this
     }
 
@@ -69,7 +92,7 @@ class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     def createdBy(alias: String): EventResponseProjection = {
-        fields.add(new GraphQLResponseField("createdBy").alias(alias))
+        add$(new GraphQLResponseField("createdBy").alias(alias))
         this
     }
 
@@ -78,9 +101,11 @@ class EventResponseProjection extends GraphQLResponseProjection {
     }
 
     def typename(alias: String): EventResponseProjection = {
-        fields.add(new GraphQLResponseField("__typename").alias(alias))
+        add$(new GraphQLResponseField("__typename").alias(alias))
         this
     }
 
+    override def deepCopy$(): EventResponseProjection = new EventResponseProjection(this)
+
 
-}
+}
\ No newline at end of file

src/test/resources/expected-classes/scala/tostring/QueryPrivateParametrizedInput.scala.txt

@@ -22,6 +22,18 @@ case class QueryPrivateParametrizedInput(
     createdAfter: java.time.ZonedDateTime
 ) extends GraphQLParametrizedInput {
 
+    override def deepCopy(): QueryPrivateParametrizedInput = {
+        QueryPrivateParametrizedInput(
+            this.int,
+            this.intOpt,
+            this.seq1,
+            this.seq2,
+            this.`new`,
+            this.enum,
+            this.createdAfter
+        )
+    }
+
     override def toString(): String = {
         scala.Seq(
             "int: " + GraphQLRequestSerializer.getEntry(int),