decouple find SchemaSegment with show index statement (#4354)

shardingsphere-sql-parser/shardingsphere-sql-parser-engine/src/main/java/org/apache/shardingsphere/sql/parser/sql/statement/dal/dialect/mysql/ShowIndexStatement.java

@@ -17,8 +17,10 @@
 
 package org.apache.shardingsphere.sql.parser.sql.statement.dal.dialect.mysql;
 
+import com.google.common.base.Optional;
 import lombok.Getter;
 import lombok.Setter;
+import org.apache.shardingsphere.sql.parser.sql.segment.generic.SchemaSegment;
 import org.apache.shardingsphere.sql.parser.sql.segment.generic.TableSegment;
 import org.apache.shardingsphere.sql.parser.sql.statement.dal.DALStatement;
 import org.apache.shardingsphere.sql.parser.sql.statement.generic.TableSegmentAvailable;
@@ -31,4 +33,15 @@ import org.apache.shardingsphere.sql.parser.sql.statement.generic.TableSegmentAv
 public final class ShowIndexStatement extends DALStatement implements TableSegmentAvailable {
     
     private TableSegment table;
+    
+    private SchemaSegment schema;
+    
+    /**
+     * Get schema.
+     * 
+     * @return schema
+     */
+    public Optional<SchemaSegment> getSchema() {
+        return Optional.fromNullable(schema);
+    }
 }

shardingsphere-sql-parser/shardingsphere-sql-parser-mysql/src/main/java/org/apache/shardingsphere/sql/parser/visitor/impl/MySQLDALVisitor.java

@@ -134,6 +134,7 @@ public final class MySQLDALVisitor extends MySQLVisitor {
             SchemaNameContext schemaNameContext = ctx.fromSchema().schemaName();
             SchemaSegment schemaSegment = new SchemaSegment(schemaNameContext.getStart().getStartIndex(), schemaNameContext.getStop().getStopIndex(), (IdentifierValue) visit(schemaNameContext));
             result.getAllSQLSegments().add(schemaSegment);
+            result.setSchema(schemaSegment);
         }
         if (null != ctx.fromTable()) {
             FromTableSegment fromTableSegment = (FromTableSegment) visitFromTable(ctx.fromTable());

shardingsphere-sql-parser/shardingsphere-sql-parser-test/src/test/java/org/apache/shardingsphere/sql/parser/integrate/asserts/statement/dal/impl/ShowIndexStatementAssert.java

@@ -23,7 +23,6 @@ import org.apache.shardingsphere.sql.parser.integrate.asserts.SQLCaseAssertConte
 import org.apache.shardingsphere.sql.parser.integrate.asserts.segment.schema.SchemaAssert;
 import org.apache.shardingsphere.sql.parser.integrate.asserts.segment.table.TableAssert;
 import org.apache.shardingsphere.sql.parser.integrate.jaxb.domain.statement.dal.ShowIndexStatementTestCase;
-import org.apache.shardingsphere.sql.parser.sql.segment.generic.SchemaSegment;
 import org.apache.shardingsphere.sql.parser.sql.statement.dal.dialect.mysql.ShowIndexStatement;
 
 import static org.junit.Assert.assertFalse;
@@ -58,10 +57,10 @@ public final class ShowIndexStatementAssert {
     
     private static void assertSchema(final SQLCaseAssertContext assertContext, final ShowIndexStatement actual, final ShowIndexStatementTestCase expected) {
         if (null != expected.getSchema()) {
-            assertTrue(assertContext.getText("Actual schema segment should exist."), actual.findSQLSegment(SchemaSegment.class).isPresent());
-            SchemaAssert.assertIs(assertContext, actual.findSQLSegment(SchemaSegment.class).get(), expected.getSchema());
+            assertTrue(assertContext.getText("Actual schema segment should exist."), actual.getSchema().isPresent());
+            SchemaAssert.assertIs(assertContext, actual.getSchema().get(), expected.getSchema());
         } else {
-            assertFalse(assertContext.getText("Actual schema segment should not exist."), actual.findSQLSegment(SchemaSegment.class).isPresent());
+            assertFalse(assertContext.getText("Actual schema segment should not exist."), actual.getSchema().isPresent());
         }
     }
 }