Support overriding FreeMarker templates #860 (#1048)

---------
Co-authored-by: NMarvin Froeder <marvin.froeder@police.govt.nz>
Co-authored-by: NBogdan Kobylynskyi <92bogdan@gmail.com>
Co-authored-by: NMarvin Froeder <velobr@gmail.com>

.gitignore

@@ -6,7 +6,10 @@ build
 modules.xml
 .idea/misc.xml
 *.ipr
-
+bin/
+.classpath
+.project
+.settings/
 
 ### Maven ###
 target/

CONTRIBUTING.md

@@ -36,8 +36,7 @@ Please follow the steps below in order to make the changes:
    ./gradlew -p plugins/gradle/graphql-java-codegen-gradle-plugin clean build
    
    # Build Maven plugin
-   cd plugins/maven/graphql-java-codegen-maven-plugin
-   mvn clean verify 
+   mvn clean verify -f plugins/maven/graphql-java-codegen-maven-plugin/pom.xml
    ```
 
 9. Make changes to the plugin code
@@ -48,8 +47,7 @@ Please follow the steps below in order to make the changes:
    ./gradlew -p plugins/gradle/graphql-java-codegen-gradle-plugin clean build publishToMavenLocal
    
    # Install Maven plugin
-   cd plugins/maven/graphql-java-codegen-maven-plugin
-   mvn clean install 
+   mvn clean install -f plugins/maven/graphql-java-codegen-maven-plugin/pom.xml
    ```
 
 11. Make sure that `example` projects are compiling and running.

plugins/gradle/graphql-java-codegen-gradle-plugin/src/main/java/io/github/kobylynskyi/graphql/codegen/gradle/GraphQLCodegenGradleTask.java

 package io.github.kobylynskyi.graphql.codegen.gradle;
 
 import com.kobylynskyi.graphql.codegen.GraphQLCodegen;
+import com.kobylynskyi.graphql.codegen.generators.FreeMarkerTemplateType;
 import com.kobylynskyi.graphql.codegen.java.JavaGraphQLCodegen;
 import com.kobylynskyi.graphql.codegen.kotlin.KotlinGraphQLCodegen;
 import com.kobylynskyi.graphql.codegen.model.ApiInterfaceStrategy;
@@ -54,6 +55,7 @@ public class GraphQLCodegenGradleTask extends DefaultTask implements GraphQLCode
 
     private Map<String, String> customTypesMapping = new HashMap<>();
     private Map<String, List<String>> customAnnotationsMapping = new HashMap<>();
+    private Map<FreeMarkerTemplateType, String> customTemplates = new HashMap<>();
     private Map<String, List<String>> directiveAnnotationsMapping = new HashMap<>();
     private String packageName;
     private String apiPackageName;
@@ -133,8 +135,8 @@ public class GraphQLCodegenGradleTask extends DefaultTask implements GraphQLCode
         mappingConfig.setPackageName(packageName);
         mappingConfig.setCustomTypesMapping(
                 customTypesMapping != null ? customTypesMapping : new HashMap<>());
-        mappingConfig.setCustomAnnotationsMapping(
-                customAnnotationsMapping != null ? customAnnotationsMapping : new HashMap<>());
+        mappingConfig.setCustomTemplates(
+                customTemplates != null ? customTemplates : new HashMap<>());
         mappingConfig.setDirectiveAnnotationsMapping(
                 directiveAnnotationsMapping != null ? directiveAnnotationsMapping : new HashMap<>());
         mappingConfig.setApiNameSuffix(apiNameSuffix);
@@ -333,6 +335,17 @@ public class GraphQLCodegenGradleTask extends DefaultTask implements GraphQLCode
         this.customTypesMapping = customTypesMapping;
     }
 
+    @Input
+    @Optional
+    @Override
+    public Map<FreeMarkerTemplateType, String> getCustomTemplates() {
+        return customTemplates;
+    }
+
+    public void setCustomTemplates(Map<FreeMarkerTemplateType, String> customTemplates) {
+        this.customTemplates = customTemplates;
+    }
+
     @Input
     @Optional
     @Override

plugins/maven/graphql-java-codegen-maven-plugin/src/main/java/io/github/kobylynskyi/graphql/codegen/GraphQLCodegenMojo.java

 package io.github.kobylynskyi.graphql.codegen;
 
 import com.kobylynskyi.graphql.codegen.GraphQLCodegen;
+import com.kobylynskyi.graphql.codegen.generators.FreeMarkerTemplateType;
 import com.kobylynskyi.graphql.codegen.java.JavaGraphQLCodegen;
 import com.kobylynskyi.graphql.codegen.kotlin.KotlinGraphQLCodegen;
 import com.kobylynskyi.graphql.codegen.model.ApiInterfaceStrategy;
@@ -65,6 +66,9 @@ public class GraphQLCodegenMojo extends AbstractMojo implements GraphQLCodegenCo
     @Parameter
     private Map<String, Properties> customAnnotationsMapping;
 
+    @Parameter
+    private Map<FreeMarkerTemplateType, String> customTemplates;
+
     @Parameter
     private Map<String, Properties> directiveAnnotationsMapping;
 
@@ -246,6 +250,7 @@ public class GraphQLCodegenMojo extends AbstractMojo implements GraphQLCodegenCo
         MappingConfig mappingConfig = new MappingConfig();
         mappingConfig.setPackageName(packageName);
         mappingConfig.setCustomTypesMapping(convertToMap(customTypesMapping));
+        mappingConfig.setCustomTemplates(customTemplates);
         mappingConfig.setCustomAnnotationsMapping(convertToListsMap(customAnnotationsMapping));
         mappingConfig.setDirectiveAnnotationsMapping(convertToListsMap(directiveAnnotationsMapping));
         mappingConfig.setApiNameSuffix(apiNameSuffix);
@@ -737,4 +742,12 @@ public class GraphQLCodegenMojo extends AbstractMojo implements GraphQLCodegenCo
         return result;
     }
 
+    @Override
+    public Map<FreeMarkerTemplateType, String> getCustomTemplates() {
+        if (customTemplates == null) {
+            return new HashMap<>();
+        }
+        return customTemplates;
+    }
+
 }

plugins/sbt/graphql-java-codegen-sbt-plugin/src/main/scala/io/github/dreamylost/graphql/codegen/GraphQLCodegenKeys.scala

@@ -3,6 +3,7 @@ package io.github.dreamylost.graphql.codegen
 import java.util
 
 import com.kobylynskyi.graphql.codegen.model._
+import com.kobylynskyi.graphql.codegen.generators._
 import sbt._
 
 /** @author
@@ -43,6 +44,8 @@ trait GraphQLCodegenKeys {
 
   val customAnnotationsMapping = settingKey[util.Map[String, util.List[String]]]("customAnnotationsMapping")
 
+  val customTemplates = settingKey[util.Map[FreeMarkerTemplateType, String]]("customTemplates")
+
   val generateEqualsAndHashCode =
     settingKey[Boolean]("Specifies whether generated model classes should have equals and hashCode methods defined.")
 

plugins/sbt/graphql-java-codegen-sbt-plugin/src/main/scala/io/github/dreamylost/graphql/codegen/GraphQLCodegenPlugin.scala

@@ -7,6 +7,7 @@ import com.kobylynskyi.graphql.codegen.model.exception.LanguageNotSupportedExcep
 import com.kobylynskyi.graphql.codegen.model.GeneratedLanguage._
 import com.kobylynskyi.graphql.codegen.scala.ScalaGraphQLCodegen
 import com.kobylynskyi.graphql.codegen.supplier._
+import com.kobylynskyi.graphql.codegen.generators.FreeMarkerTemplateType
 import sbt.{ AutoPlugin, PluginTrigger, _ }
 import sbt.Keys.{ sLog, sourceManaged, _ }
 import sbt.internal.util.complete.DefaultParsers.spaceDelimited
@@ -67,6 +68,7 @@ class GraphQLCodegenPlugin(configuration: Configuration, private[codegen] val co
     generateJacksonTypeIdResolver       := MappingConfigConstants.DEFAULT_GENERATE_JACKSON_TYPE_ID_RESOLVER,
     customTypesMapping                  := new JHashMap[String, String](), // TODO use scala Map, convert to java Map
     customAnnotationsMapping            := new JHashMap[String, JList[String]](),
+    customTemplates                     := new JHashMap[FreeMarkerTemplateType, String](),
     directiveAnnotationsMapping         := new JHashMap[String, JList[String]](),
     javaxValidationApiVersion           := None,
     graphqlJavaCodegenVersion           := None,
@@ -118,17 +120,17 @@ class GraphQLCodegenPlugin(configuration: Configuration, private[codegen] val co
     generateBuilder                               := MappingConfigConstants.DEFAULT_BUILDER,
     generateApis                                  := MappingConfigConstants.DEFAULT_GENERATE_APIS,
     generateEqualsAndHashCode                     := MappingConfigConstants.DEFAULT_EQUALS_AND_HASHCODE,
-    generateImmutableModels                       := MappingConfigConstants.DEFAULT_GENERATE_IMMUTABLE_MODELS, // TODO change default value
-    generateToString                              := MappingConfigConstants.DEFAULT_TO_STRING,
+    generateImmutableModels := MappingConfigConstants.DEFAULT_GENERATE_IMMUTABLE_MODELS, // TODO change default value
+    generateToString        := MappingConfigConstants.DEFAULT_TO_STRING,
     // parent interfaces configs:
-    parentInterfaces                              := parentInterfacesConfig,
-    generateAllMethodInProjection                 := MappingConfigConstants.DEFAULT_GENERATE_ALL_METHOD,
-    responseProjectionMaxDepth                    := MappingConfigConstants.DEFAULT_RESPONSE_PROJECTION_MAX_DEPTH,
-    supportUnknownFields                          := MappingConfigConstants.DEFAULT_SUPPORT_UNKNOWN_FIELDS,
-    unknownFieldsPropertyName                     := MappingConfigConstants.DEFAULT_UNKNOWN_FIELDS_PROPERTY_NAME,
-    generateNoArgsConstructorOnly                 := MappingConfigConstants.DEFAULT_GENERATE_NOARGS_CONSTRUCTOR_ONLY,
-    generateModelsWithPublicFields                := MappingConfigConstants.DEFAULT_GENERATE_MODELS_WITH_PUBLIC_FIELDS,
-    skip                                          := false
+    parentInterfaces               := parentInterfacesConfig,
+    generateAllMethodInProjection  := MappingConfigConstants.DEFAULT_GENERATE_ALL_METHOD,
+    responseProjectionMaxDepth     := MappingConfigConstants.DEFAULT_RESPONSE_PROJECTION_MAX_DEPTH,
+    supportUnknownFields           := MappingConfigConstants.DEFAULT_SUPPORT_UNKNOWN_FIELDS,
+    unknownFieldsPropertyName      := MappingConfigConstants.DEFAULT_UNKNOWN_FIELDS_PROPERTY_NAME,
+    generateNoArgsConstructorOnly  := MappingConfigConstants.DEFAULT_GENERATE_NOARGS_CONSTRUCTOR_ONLY,
+    generateModelsWithPublicFields := MappingConfigConstants.DEFAULT_GENERATE_MODELS_WITH_PUBLIC_FIELDS,
+    skip                           := false
   )
 
   private def getMappingConfig(): Def.Initialize[MappingConfig] = Def.setting {
@@ -149,6 +151,7 @@ class GraphQLCodegenPlugin(configuration: Configuration, private[codegen] val co
     mappingConfig.setTypeResolverPrefix((GraphQLCodegenConfig / typeResolverPrefix).value.orNull)
     mappingConfig.setModelValidationAnnotation((GraphQLCodegenConfig / modelValidationAnnotation).value)
     mappingConfig.setCustomAnnotationsMapping((GraphQLCodegenConfig / customAnnotationsMapping).value)
+    mappingConfig.setCustomTemplates((GraphQLCodegenConfig / customTemplates).value)
     mappingConfig.setGenerateEqualsAndHashCode((GraphQLCodegenConfig / generateEqualsAndHashCode).value)
     mappingConfig.setGenerateImmutableModels((GraphQLCodegenConfig / generateImmutableModels).value)
     mappingConfig.setGenerateToString((GraphQLCodegenConfig / generateToString).value)

src/main/java/com/kobylynskyi/graphql/codegen/generators/FreeMarkerTemplateFilesCreator.java

@@ -48,7 +48,7 @@ public class FreeMarkerTemplateFilesCreator {
         }
 
         try (FileWriter fileWriter = new FileWriter(javaSourceFile)) {
-            Template template = FreeMarkerTemplatesRegistry.getTemplateWithLang(language, templateType);
+            Template template = getTemplateForTypeAndLanguage(mappingContext, templateType, language);
             template.process(dataModel, fileWriter);
         } catch (Exception e) {
             throw new UnableToCreateFileException(e);
@@ -56,6 +56,20 @@ public class FreeMarkerTemplateFilesCreator {
         return javaSourceFile;
     }
 
+    private static Template getTemplateForTypeAndLanguage(MappingContext mappingContext,
+                                                          FreeMarkerTemplateType templateType,
+                                                          GeneratedLanguage language) {
+        String templatePath = null;
+        if (mappingContext.getCustomTemplates() != null) {
+            templatePath = mappingContext.getCustomTemplates().get(templateType);
+        }
+        if (templatePath != null) {
+            return FreeMarkerTemplatesRegistry.getCustomTemplates(templatePath);
+        } else {
+            return FreeMarkerTemplatesRegistry.getTemplateWithLang(language, templateType);
+        }
+    }
+
     private static File getFileTargetDirectory(Map<String, Object> dataModel, File outputDir) {
         File targetDir;
         Object packageName = dataModel.get(DataModelFields.PACKAGE);

src/main/java/com/kobylynskyi/graphql/codegen/generators/FreeMarkerTemplatesRegistry.java

@@ -22,9 +22,9 @@ class FreeMarkerTemplatesRegistry {
     private static final EnumMap<GeneratedLanguage, EnumMap<FreeMarkerTemplateType, Template>> templateMap =
             new EnumMap<>(GeneratedLanguage.class);
 
+    private static final Configuration configuration = buildFreeMarkerTemplateConfiguration();
+    
     static {
-        Configuration configuration = buildFreeMarkerTemplateConfiguration();
-
         try {
             templateMap.put(GeneratedLanguage.JAVA, getTemplates(configuration, GeneratedLanguage.JAVA));
             templateMap.put(GeneratedLanguage.SCALA, getTemplates(configuration, GeneratedLanguage.SCALA));
@@ -70,4 +70,12 @@ class FreeMarkerTemplatesRegistry {
         return configuration;
     }
 
+    public static Template getCustomTemplates(String templatePath) {
+        try {
+            return configuration.getTemplate(templatePath);
+        } catch (IOException e) {
+            throw new UnableToLoadFreeMarkerTemplateException(e);
+        }
+    }
+
 }

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

 package com.kobylynskyi.graphql.codegen.model;
 
+import com.kobylynskyi.graphql.codegen.generators.FreeMarkerTemplateType;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -27,6 +28,13 @@ public interface GraphQLCodegenConfiguration {
      * @return mappings from GraphqlType to JavaType
      */
     Map<String, String> getCustomTypesMapping();
+    
+    /**
+     * Can be used to supply paths to custom FreeMarker templates for code generation.
+     *
+     * @return a map, where key is a tempalte type and a value is path to a FreeMarker template
+     */
+    Map<FreeMarkerTemplateType, String> getCustomTemplates();
 
     /**
      * Can be used to supply custom annotations (serializers) for scalars.

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

 package com.kobylynskyi.graphql.codegen.model;
 
+import com.kobylynskyi.graphql.codegen.generators.FreeMarkerTemplateType;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -85,6 +86,7 @@ public class MappingConfig implements GraphQLCodegenConfiguration, Combinable<Ma
     private Set<String> parametrizedResolverAnnotations = new HashSet<>();
 
     private Map<String, String> customTypesMapping = new HashMap<>();
+    private Map<FreeMarkerTemplateType, String> customTemplates = new HashMap<>();
 
     private Set<String> typesAsInterfaces = new HashSet<>();
 
@@ -94,9 +96,9 @@ public class MappingConfig implements GraphQLCodegenConfiguration, Combinable<Ma
 
     private GeneratedLanguage generatedLanguage;
 
-    private static <T> Map<String, T> combineMap(Map<String, T> thisMap, Map<String, T> otherMap) {
+    private static <K, T> Map<K, T> combineMap(Map<K, T> thisMap, Map<K, T> otherMap) {
         if (thisMap != null && otherMap != null) {
-            Map<String, T> resultMap = new HashMap<>();
+            Map<K, T> resultMap = new HashMap<>();
             resultMap.putAll(thisMap);
             resultMap.putAll(otherMap);
             return resultMap;
@@ -186,6 +188,7 @@ public class MappingConfig implements GraphQLCodegenConfiguration, Combinable<Ma
         fieldsWithResolvers = combineSet(fieldsWithResolvers, source.fieldsWithResolvers);
         fieldsWithoutResolvers = combineSet(fieldsWithoutResolvers, source.fieldsWithoutResolvers);
         customTypesMapping = combineMap(customTypesMapping, source.customTypesMapping);
+        customTemplates = combineMap(customTemplates, source.customTemplates);
         customAnnotationsMapping = combineMap(customAnnotationsMapping, source.customAnnotationsMapping);
         directiveAnnotationsMapping = combineMap(directiveAnnotationsMapping, source.directiveAnnotationsMapping);
         resolverArgumentAnnotations = combineSet(resolverArgumentAnnotations, source.resolverArgumentAnnotations);
@@ -244,6 +247,28 @@ public class MappingConfig implements GraphQLCodegenConfiguration, Combinable<Ma
         this.customTypesMapping = customTypesMapping;
     }
 
+    /**
+     * Provide a path to a custom template for the specific FreeMarker template type (if absent).
+     *
+     * @param from the from
+     * @param to   the to
+     */
+    public void putCustomTemplatesIfAbsent(FreeMarkerTemplateType from, String to) {
+        if (customTemplates == null) {
+            customTemplates = new HashMap<>();
+        }
+        customTemplates.computeIfAbsent(from, k -> to);
+    }
+
+    @Override
+    public Map<FreeMarkerTemplateType, String> getCustomTemplates() {
+        return customTemplates;
+    }
+
+    public void setCustomTemplates(Map<FreeMarkerTemplateType, String> customTemplates) {
+        this.customTemplates = customTemplates;
+    }
+
     @Override
     public Map<String, List<String>> getCustomAnnotationsMapping() {
         return customAnnotationsMapping;

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

 package com.kobylynskyi.graphql.codegen.model;
 
+import com.kobylynskyi.graphql.codegen.generators.FreeMarkerTemplateType;
 import com.kobylynskyi.graphql.codegen.mapper.DataModelMapper;
 import com.kobylynskyi.graphql.codegen.mapper.DataModelMapperFactory;
 import com.kobylynskyi.graphql.codegen.mapper.FieldDefinitionToParameterMapper;
@@ -83,6 +84,11 @@ public class MappingContext implements GraphQLCodegenConfiguration {
     public Map<String, String> getCustomTypesMapping() {
         return config.getCustomTypesMapping();
     }
+    
+    @Override
+    public Map<FreeMarkerTemplateType, String> getCustomTemplates() {
+        return config.getCustomTemplates();
+    }
 
     @Override
     public Map<String, List<String>> getCustomAnnotationsMapping() {

src/test/java/com/kobylynskyi/graphql/codegen/GraphQLCodegenCustomTemplatesTest.java

+package com.kobylynskyi.graphql.codegen;
+
+import com.kobylynskyi.graphql.codegen.generators.FreeMarkerTemplateType;
+import com.kobylynskyi.graphql.codegen.java.JavaGraphQLCodegen;
+import com.kobylynskyi.graphql.codegen.model.MappingConfig;
+import com.kobylynskyi.graphql.codegen.utils.Utils;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Objects;
+
+import static com.kobylynskyi.graphql.codegen.TestUtils.assertFileContainsElements;
+import static java.util.Collections.singletonList;
+
+class GraphQLCodegenCustomTemplatesTest {
+
+    private final File outputBuildDir = new File("build/generated");
+    private final File outputJavaClassesDir = new File("build/generated/com/kobylynskyi/graphql/test1");
+
+    private MappingConfig mappingConfig;
+
+    @BeforeEach
+    void init() {
+        mappingConfig = new MappingConfig();
+        mappingConfig.setPackageName("com.kobylynskyi.graphql.test1");
+        mappingConfig.setGenerateClient(true);
+    }
+
+    @AfterEach
+    void cleanup() {
+        Utils.deleteDir(outputBuildDir);
+    }
+
+    @Test
+    void generate_CustomTemplates_Type() throws Exception {
+        mappingConfig.putCustomTemplatesIfAbsent(FreeMarkerTemplateType.TYPE, "/template/record_type.ftl");
+
+        generate("src/test/resources/schemas/test.graphqls");
+
+        File[] files = Objects.requireNonNull(outputJavaClassesDir.listFiles());
+        assertFileContainsElements(files, "Event.java",
+                "public record Event (");
+    }
+
+    private void generate(String path) throws IOException {
+        new JavaGraphQLCodegen(singletonList(path),
+                outputBuildDir, mappingConfig, TestUtils.getStaticGeneratedInfo(mappingConfig))
+                .generate();
+    }
+
+}

src/test/resources/template/record_type.ftl

+<#assign MapperUtil=statics["com.kobylynskyi.graphql.codegen.java.JavaGraphQLTypeMapper"]>
+<#if package?has_content>
+package ${package};
+</#if>
+
+public record ${className} (
+<#if fields?has_content>
+    <#list fields as field>
+    ${field.type} ${field.name}<#if field.defaultValue?has_content> = ${field.defaultValue}</#if><#if field?has_next>,</#if>
+    </#list>
+</#if>
+)
+{
+
+    public ${className}() {
+	    <#list fields as field><#if field.defaultValue?has_content> ${field.name} = ${field.defaultValue};</#if></#list>
+    }
+
+}