#12 Allowing delegation to other mapper classes

core/src/main/java/org/mapstruct/Mapper.java

@@ -29,4 +29,5 @@ import java.lang.annotation.Target;
 @Target(ElementType.TYPE)
 @Retention(RetentionPolicy.SOURCE)
 public @interface Mapper {
+	Class<?>[] uses() default { };
 }

core/src/main/java/org/mapstruct/Mapping.java

@@ -15,15 +15,9 @@
  */
 package org.mapstruct;
 
-import org.mapstruct.converter.Converter;
-import org.mapstruct.converter.NoOpConverter;
-
 public @interface Mapping {
 
 	String source();
 
 	String target();
-
-	Class<? extends Converter<?, ?>> converter() default NoOpConverter.class;
-
 }

core/src/main/java/org/mapstruct/converter/Converter.java

@@ -1,23 +0,0 @@
-/**
- *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
- *
- *  Licensed under the Apache License, Version 2.0 (the "License");
- *  you may not use this file except in compliance with the License.
- *  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS,
- *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
- */
-package org.mapstruct.converter;
-
-public interface Converter<S, T> {
-
-	T from(S source);
-
-	S to(T target);
-}

core/src/main/java/org/mapstruct/converter/NoOpConverter.java

@@ -1,29 +0,0 @@
-/**
- *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
- *
- *  Licensed under the Apache License, Version 2.0 (the "License");
- *  you may not use this file except in compliance with the License.
- *  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS,
- *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
- */
-package org.mapstruct.converter;
-
-public class NoOpConverter implements Converter<Object, Object> {
-
-	@Override
-	public Object from(Object source) {
-		return source;
-	}
-
-	@Override
-	public Object to(Object target) {
-		return target;
-	}
-}

core/src/test/java/org/mapstruct/MappersTest.java

@@ -16,7 +16,6 @@
 package org.mapstruct;
 
 
-import org.mapstruct.Mappers;
 import org.mapstruct.test.model.Foo;
 import org.testng.annotations.Test;
 

pom.xml

@@ -37,5 +37,5 @@
         <module>core</module>
         <module>processor</module>
         <module>integrationtest</module>
-  </modules>
+    </modules>
 </project>

processor/src/main/java/org/mapstruct/ap/MapperGenerationVisitor.java

@@ -29,7 +29,9 @@ import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
+import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.TypeKind;
+import javax.lang.model.type.TypeMirror;
 import javax.lang.model.util.ElementKindVisitor6;
 import javax.lang.model.util.Elements;
 import javax.lang.model.util.Types;
@@ -91,18 +93,34 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 	}
 
 	private Mapper retrieveModel(TypeElement element) {
-		List<Method> methods = retrieveMethods( element );
+		List<Method> methods = retrieveMethods( null, element );
-		Set<Method> processedMethods = new HashSet<Method>();
+		List<BeanMapping> mappings = getMappings( methods );
-		List<BeanMapping> mappings = new ArrayList<BeanMapping>();
+		List<Type> usedMapperTypes = getUsedMapperTypes( element );
 
+		Mapper mapper = new Mapper(
+				elementUtils.getPackageOf( element ).getQualifiedName().toString(),
+				element.getSimpleName().toString(),
+				element.getSimpleName() + IMPLEMENTATION_SUFFIX,
+				mappings,
+				usedMapperTypes
+		);
+
+		return mapper;
+	}
+
+	private List<BeanMapping> getMappings(List<Method> methods) {
 		Conversions conversions = new Conversions( elementUtils, typeUtils, typeUtil );
 
+		List<BeanMapping> mappings = new ArrayList<BeanMapping>();
+		Set<Method> processedMethods = new HashSet<Method>();
+
 		for ( Method method : methods ) {
 			if ( processedMethods.contains( method ) ) {
 				continue;
 			}
 
 			MappingMethod mappingMethod = new MappingMethod(
+					method.getDeclaringMapper(),
 					method.getName(),
 					method.getParameterName(),
 					getElementMappingMethod( methods, method )
@@ -114,6 +132,7 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 				processedMethods.add( rawReverseMappingMethod );
 
 				reverseMappingMethod = new MappingMethod(
+						rawReverseMappingMethod.getDeclaringMapper(),
 						rawReverseMappingMethod.getName(),
 						rawReverseMappingMethod.getParameterName(),
 						getElementMappingMethod( methods, rawReverseMappingMethod )
@@ -134,12 +153,13 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 								property.getSourceType(),
 								property.getTargetName(),
 								property.getTargetType(),
-								property.getConverterType(),
 								propertyMappingMethod != null ? new MappingMethod(
+										propertyMappingMethod.getDeclaringMapper(),
 										propertyMappingMethod.getName(),
 										propertyMappingMethod.getParameterName()
 								) : null,
 								reversePropertyMappingMethod != null ? new MappingMethod(
+										reversePropertyMappingMethod.getDeclaringMapper(),
 										reversePropertyMappingMethod.getName(),
 										reversePropertyMappingMethod.getParameterName()
 								) : null,
@@ -168,15 +188,16 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 
 			mappings.add( mapping );
 		}
+		return mappings;
+	}
 
-		Mapper mapper = new Mapper(
+	private List<Type> getUsedMapperTypes(TypeElement element) {
-				elementUtils.getPackageOf( element ).getQualifiedName().toString(),
+		List<Type> usedMapperTypes = new LinkedList<Type>();
-				element.getSimpleName().toString(),
+		MapperPrism mapperPrism = MapperPrism.getInstanceOn( element );
-				element.getSimpleName() + IMPLEMENTATION_SUFFIX,
+		for ( TypeMirror usedMapper : mapperPrism.uses() ) {
-				mappings
+			usedMapperTypes.add( typeUtil.retrieveType( usedMapper ) );
-		);
+		}
-
+		return usedMapperTypes;
-		return mapper;
 	}
 
 	private String getAccessor(String name) {
@@ -196,6 +217,7 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 			}
 		}
 		return elementMappingMethod == null ? null : new MappingMethod(
+				elementMappingMethod.getDeclaringMapper(),
 				elementMappingMethod.getName(),
 				elementMappingMethod.getParameterName()
 		);
@@ -231,7 +253,7 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 		return null;
 	}
 
-	private List<Method> retrieveMethods(TypeElement element) {
+	private List<Method> retrieveMethods(Type declaringMapper, Element element) {
 		List<Method> methods = new ArrayList<Method>();
 
 		for ( ExecutableElement method : methodsIn( element.getEnclosedElements() ) ) {
@@ -241,6 +263,7 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 
 			methods.add(
 					new Method(
+							declaringMapper,
 							method.getSimpleName().toString(),
 							parameter.getName(),
 							parameter.getType(),
@@ -250,6 +273,21 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 			);
 		}
 
+		List<Type> usedMapperTypes = new LinkedList<Type>();
+		MapperPrism mapperPrism = MapperPrism.getInstanceOn( element );
+
+		if ( mapperPrism != null ) {
+			for ( TypeMirror usedMapper : mapperPrism.uses() ) {
+				methods.addAll(
+						retrieveMethods(
+								typeUtil.retrieveType( usedMapper ),
+								( (DeclaredType) usedMapper ).asElement()
+						)
+				);
+			}
+		}
+
+
 		return methods;
 	}
 
@@ -291,8 +329,7 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 									sourcePropertyName,
 									retrieveReturnType( getterMethod ),
 									mapping != null ? mapping.getTargetName() : targetPropertyName,
-									retrieveParameter( setterMethod ).getType(),
+									retrieveParameter( setterMethod ).getType()
-									mapping != null ? mapping.getConverterType() : null
 							)
 					);
 				}
@@ -320,12 +357,7 @@ public class MapperGenerationVisitor extends ElementKindVisitor6<Void, Void> {
 	}
 
 	private Mapping getMapping(MappingPrism mapping) {
-		Type converterType = typeUtil.retrieveType( mapping.converter() );
+		return new Mapping( mapping.source(), mapping.target() );
-		return new Mapping(
-				mapping.source(),
-				mapping.target(),
-				converterType.getName().equals( "NoOpConverter" ) ? null : converterType
-		);
 	}
 
 	private Parameter retrieveParameter(ExecutableElement method) {

processor/src/main/java/org/mapstruct/ap/model/Mapper.java

@@ -20,19 +20,18 @@ import java.util.List;
 public class Mapper {
 
 	private final String packageName;
-
 	private final String interfaceName;
-
 	private final String implementationName;
-
 	private final List<BeanMapping> beanMappings;
+	private final List<Type> usedMapperTypes;
 
 	public Mapper(String packageName, String interfaceName,
-				  String implementationName, List<BeanMapping> beanMappings) {
+				  String implementationName, List<BeanMapping> beanMappings, List<Type> usedMapperTypes) {
 		this.packageName = packageName;
 		this.interfaceName = interfaceName;
 		this.implementationName = implementationName;
 		this.beanMappings = beanMappings;
+		this.usedMapperTypes = usedMapperTypes;
 	}
 
 	public String getPackageName() {
@@ -50,4 +49,8 @@ public class Mapper {
 	public List<BeanMapping> getBeanMappings() {
 		return beanMappings;
 	}
+
+	public List<Type> getUsedMapperTypes() {
+		return usedMapperTypes;
+	}
 }

processor/src/main/java/org/mapstruct/ap/model/MappingMethod.java

@@ -17,22 +17,29 @@ package org.mapstruct.ap.model;
 
 public class MappingMethod {
 
+	private final Type declaringMapper;
 	private final String name;
 	private final String parameterName;
 	private final MappingMethod elementMappingMethod;
 
-	public MappingMethod(String name, String parameterName) {
+	public MappingMethod(Type declaringMapper, String name, String parameterName) {
+		this.declaringMapper = declaringMapper;
 		this.name = name;
 		this.parameterName = parameterName;
 		this.elementMappingMethod = null;
 	}
 
-	public MappingMethod(String name, String parameterName, MappingMethod elementMappingMethod) {
+	public MappingMethod(Type declaringMapper, String name, String parameterName, MappingMethod elementMappingMethod) {
+		this.declaringMapper = declaringMapper;
 		this.name = name;
 		this.parameterName = parameterName;
 		this.elementMappingMethod = elementMappingMethod;
 	}
 
+	public Type getDeclaringMapper() {
+		return declaringMapper;
+	}
+
 	public String getName() {
 		return name;
 	}
@@ -44,4 +51,8 @@ public class MappingMethod {
 	public MappingMethod getElementMappingMethod() {
 		return elementMappingMethod;
 	}
+
+	public boolean isGenerationRequired() {
+		return declaringMapper == null;
+	}
 }

processor/src/main/java/org/mapstruct/ap/model/PropertyMapping.java

@@ -21,18 +21,16 @@ public class PropertyMapping {
 	private final Type sourceType;
 	private final String targetName;
 	private final Type targetType;
-	private final Type converterType;
 	private final MappingMethod mappingMethod;
 	private final MappingMethod reverseMappingMethod;
 	private final String toConversion;
 	private final String fromConversion;
 
-	public PropertyMapping(String sourceName, Type sourceType, String targetName, Type targetType, Type converterType, MappingMethod mappingMethod, MappingMethod reverseMappingMethod, String toConversion, String fromConversion) {
+	public PropertyMapping(String sourceName, Type sourceType, String targetName, Type targetType, MappingMethod mappingMethod, MappingMethod reverseMappingMethod, String toConversion, String fromConversion) {
 		this.sourceName = sourceName;
 		this.sourceType = sourceType;
 		this.targetName = targetName;
 		this.targetType = targetType;
-		this.converterType = converterType;
 		this.mappingMethod = mappingMethod;
 		this.reverseMappingMethod = reverseMappingMethod;
 		this.toConversion = toConversion;
@@ -55,10 +53,6 @@ public class PropertyMapping {
 		return targetType;
 	}
 
-	public Type getConverterType() {
-		return converterType;
-	}
-
 	public MappingMethod getMappingMethod() {
 		return mappingMethod;
 	}

processor/src/main/java/org/mapstruct/ap/model/source/MappedProperty.java

@@ -23,15 +23,12 @@ public class MappedProperty {
 	private final Type sourceType;
 	private final String targetName;
 	private final Type targetType;
-	private final Type converterType;
 
-	public MappedProperty(String sourceName, Type sourceType, String targetName,
+	public MappedProperty(String sourceName, Type sourceType, String targetName, Type targetType) {
-						  Type targetType, Type converterType) {
 		this.sourceName = sourceName;
 		this.sourceType = sourceType;
 		this.targetName = targetName;
 		this.targetType = targetType;
-		this.converterType = converterType;
 	}
 
 	public String getSourceName() {
@@ -50,12 +47,8 @@ public class MappedProperty {
 		return targetType;
 	}
 
-	public Type getConverterType() {
-		return converterType;
-	}
-
 	@Override
 	public String toString() {
-		return sourceType + " " + sourceName + " <=> " + targetType + " " + targetName + " (" + ( converterType != null ? converterType : "no converter" ) + ")";
+		return sourceType + " " + sourceName + " <=> " + targetType + " " + targetName;
 	}
 }

processor/src/main/java/org/mapstruct/ap/model/source/Mapping.java

@@ -15,18 +15,14 @@
  */
 package org.mapstruct.ap.model.source;
 
-import org.mapstruct.ap.model.Type;
-
 public class Mapping {
 
 	private final String sourceName;
 	private final String targetName;
-	private final Type converterType;
 
-	public Mapping(String sourceName, String targetName, Type converterType) {
+	public Mapping(String sourceName, String targetName) {
 		this.sourceName = sourceName;
 		this.targetName = targetName;
-		this.converterType = converterType;
 	}
 
 	public String getSourceName() {
@@ -36,8 +32,4 @@ public class Mapping {
 	public String getTargetName() {
 		return targetName;
 	}
-
-	public Type getConverterType() {
-		return converterType;
-	}
 }

processor/src/main/java/org/mapstruct/ap/model/source/Method.java

@@ -22,6 +22,7 @@ import org.mapstruct.ap.model.Type;
 
 public class Method {
 
+	private final Type declaringMapper;
 	private final String name;
 	private final String parameterName;
 	private final Type sourceType;
@@ -29,6 +30,11 @@ public class Method {
 	private final List<MappedProperty> mappedProperties;
 
 	public Method(String name, String parameterName, Type sourceType, Type targetType, List<MappedProperty> mappedProperties) {
+		this( null, name, parameterName, sourceType, targetType, mappedProperties );
+	}
+
+	public Method(Type declaringMapper, String name, String parameterName, Type sourceType, Type targetType, List<MappedProperty> mappedProperties) {
+		this.declaringMapper = declaringMapper;
 		this.name = name;
 		this.parameterName = parameterName;
 		this.sourceType = sourceType;
@@ -36,6 +42,10 @@ public class Method {
 		this.mappedProperties = mappedProperties;
 	}
 
+	public Type getDeclaringMapper() {
+		return declaringMapper;
+	}
+
 	public String getName() {
 		return name;
 	}
@@ -58,12 +68,12 @@ public class Method {
 
 	public boolean reverses(Method method) {
 		return
-			equals( sourceType, method.getTargetType() ) &&
+				equals( sourceType, method.getTargetType() ) &&
-			equals( targetType, method.getSourceType() );
+						equals( targetType, method.getSourceType() );
 	}
-	
+
 	private boolean equals(Object o1, Object o2) {
-	    return (o1 == null && o2 == null) || (o1 != null) && o1.equals( o2 );
+		return ( o1 == null && o2 == null ) || ( o1 != null ) && o1.equals( o2 );
 	}
 
 	@Override

processor/src/main/resources/mapper-implementation.ftl

@@ -20,6 +20,7 @@ package ${packageName};
 import java.util.ArrayList;
 import java.util.List;
 import javax.annotation.Generated;
+import java.util.Date;
 
 @Generated(
     value = "org.mapstruct.ap.MappingProcessor",
@@ -27,7 +28,12 @@ import javax.annotation.Generated;
 )
 public class ${implementationName} implements ${interfaceName} {
 
+    <#list usedMapperTypes as mapperType>
+    private final ${mapperType.name} ${mapperType.name?uncap_first} = new ${mapperType.name}();
+    </#list>
+
     <#list beanMappings as beanMapping>
+    <#if beanMapping.mappingMethod.generationRequired == true>
     <#if beanMapping.iterableMapping == true>
     @Override
     public ${beanMapping.targetType.name}<${beanMapping.targetType.elementType.name}> ${beanMapping.mappingMethod.name}(${beanMapping.sourceType.name}<${beanMapping.sourceType.elementType.name}> ${beanMapping.mappingMethod.parameterName}) {
@@ -53,18 +59,20 @@ public class ${implementationName} implements ${interfaceName} {
         ${beanMapping.targetType.name} ${beanMapping.targetType.name?uncap_first} = new ${beanMapping.targetType.name}();
 
         <#list beanMapping.propertyMappings as propertyMapping>
+        <#-- primitive conversion -->
         <#if propertyMapping.toConversion??>
-        <#if propertyMapping.targetType.primitive == true>
+            <#if propertyMapping.targetType.primitive == true>
         if( ${beanMapping.mappingMethod.parameterName}.get${propertyMapping.sourceName?cap_first}() != null ) {
             ${beanMapping.targetType.name?uncap_first}.set${propertyMapping.targetName?cap_first}( ${propertyMapping.toConversion} );
         }
-        <#else>
+            <#else>
         ${beanMapping.targetType.name?uncap_first}.set${propertyMapping.targetName?cap_first}( ${propertyMapping.toConversion} );
-        </#if>
+            </#if>
         <#elseif propertyMapping.converterType??>
         ${beanMapping.targetType.name?uncap_first}.set${propertyMapping.targetName?cap_first}( new ${propertyMapping.converterType.name}().from( ${beanMapping.mappingMethod.parameterName}.get${propertyMapping.sourceName?cap_first}() ) );
+        <#-- invoke mapping method -->
         <#elseif propertyMapping.mappingMethod??>
-        ${beanMapping.targetType.name?uncap_first}.set${propertyMapping.targetName?cap_first}( ${propertyMapping.mappingMethod.name}( ${beanMapping.mappingMethod.parameterName}.get${propertyMapping.sourceName?cap_first}() ) );
+        ${beanMapping.targetType.name?uncap_first}.set${propertyMapping.targetName?cap_first}( <#if propertyMapping.mappingMethod.declaringMapper??>${propertyMapping.mappingMethod.declaringMapper.name?uncap_first}.</#if>${propertyMapping.mappingMethod.name}( ${beanMapping.mappingMethod.parameterName}.get${propertyMapping.sourceName?cap_first}() ) );
         <#else>
         ${beanMapping.targetType.name?uncap_first}.set${propertyMapping.targetName?cap_first}( ${beanMapping.mappingMethod.parameterName}.get${propertyMapping.sourceName?cap_first}() );
         </#if>
@@ -73,8 +81,10 @@ public class ${implementationName} implements ${interfaceName} {
         return ${beanMapping.targetType.name?uncap_first};
     }
     </#if>
+    </#if>
 
     <#if beanMapping.reverseMappingMethod??>
+    <#if beanMapping.reverseMappingMethod.generationRequired == true>
     <#if beanMapping.iterableMapping == true>
     @Override
     public ${beanMapping.sourceType.name}<${beanMapping.sourceType.elementType.name}> ${beanMapping.reverseMappingMethod.name}(${beanMapping.targetType.name}<${beanMapping.targetType.elementType.name}> ${beanMapping.reverseMappingMethod.parameterName}) {
@@ -101,17 +111,18 @@ public class ${implementationName} implements ${interfaceName} {
 
         <#list beanMapping.propertyMappings as propertyMapping>
         <#if propertyMapping.fromConversion??>
-        <#if propertyMapping.sourceType.primitive == true>
+            <#if propertyMapping.sourceType.primitive == true>
         if( ${beanMapping.reverseMappingMethod.parameterName}.get${propertyMapping.targetName?cap_first}() != null ) {
             ${beanMapping.sourceType.name?uncap_first}.set${propertyMapping.sourceName?cap_first}( ${propertyMapping.fromConversion} );
         }
-        <#else>
+            <#else>
         ${beanMapping.sourceType.name?uncap_first}.set${propertyMapping.sourceName?cap_first}( ${propertyMapping.fromConversion} );
-        </#if>
+            </#if>
         <#elseif propertyMapping.converterType??>
         ${beanMapping.sourceType.name?uncap_first}.set${propertyMapping.sourceName?cap_first}( new ${propertyMapping.converterType.name}().to( ${beanMapping.reverseMappingMethod.parameterName}.get${propertyMapping.targetName?cap_first}() ) );
+        <#-- invoke mapping method -->
         <#elseif propertyMapping.reverseMappingMethod??>
-        ${beanMapping.sourceType.name?uncap_first}.set${propertyMapping.sourceName?cap_first}( ${propertyMapping.reverseMappingMethod.name}( ${beanMapping.reverseMappingMethod.parameterName}.get${propertyMapping.targetName?cap_first}() ) );
+        ${beanMapping.sourceType.name?uncap_first}.set${propertyMapping.sourceName?cap_first}( <#if propertyMapping.reverseMappingMethod.declaringMapper??>${propertyMapping.reverseMappingMethod.declaringMapper.name?uncap_first}.</#if>${propertyMapping.reverseMappingMethod.name}( ${beanMapping.reverseMappingMethod.parameterName}.get${propertyMapping.targetName?cap_first}() ) );
         <#else>
         ${beanMapping.sourceType.name?uncap_first}.set${propertyMapping.sourceName?cap_first}( ${beanMapping.reverseMappingMethod.parameterName}.get${propertyMapping.targetName?cap_first}() );
         </#if>
@@ -121,6 +132,7 @@ public class ${implementationName} implements ${interfaceName} {
     }    
     </#if>
     </#if>
+    </#if>
     
     </#list>
 }

processor/src/test/java/org/mapstruct/ap/test/CarMapperTest.java

@@ -18,6 +18,7 @@ package org.mapstruct.ap.test;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.GregorianCalendar;
 import java.util.List;
 import javax.tools.DiagnosticCollector;
 import javax.tools.JavaFileObject;
@@ -26,7 +27,7 @@ import org.mapstruct.ap.test.model.Car;
 import org.mapstruct.ap.test.model.CarDto;
 import org.mapstruct.ap.test.model.CarMapper;
 import org.mapstruct.ap.test.model.Category;
-import org.mapstruct.ap.test.model.IntToStringConverter;
+import org.mapstruct.ap.test.model.DateMapper;
 import org.mapstruct.ap.test.model.Person;
 import org.mapstruct.ap.test.model.PersonDto;
 import org.testng.annotations.BeforeMethod;
@@ -51,8 +52,8 @@ public class CarMapperTest extends MapperTestBase {
 				Person.class,
 				PersonDto.class,
 				CarMapper.class,
-				IntToStringConverter.class,
+				Category.class,
-				Category.class
+				DateMapper.class
 		);
 
 		boolean compilationSuccessful = compile( diagnostics, sourceFiles );
@@ -69,7 +70,13 @@ public class CarMapperTest extends MapperTestBase {
 	@Test
 	public void shouldMapAttributeByName() {
 		//given
-		Car car = new Car( "Morris", 2, 1980, new Person( "Bob" ), new ArrayList<Person>() );
+		Car car = new Car(
+				"Morris",
+				2,
+				new GregorianCalendar( 1980, 0, 1 ).getTime(),
+				new Person( "Bob" ),
+				new ArrayList<Person>()
+		);
 
 		//when
 		CarDto carDto = CarMapper.INSTANCE.carToCarDto( car );
@@ -82,7 +89,13 @@ public class CarMapperTest extends MapperTestBase {
 	@Test
 	public void shouldMapReferenceAttribute() {
 		//given
-		Car car = new Car( "Morris", 2, 1980, new Person( "Bob" ), new ArrayList<Person>() );
+		Car car = new Car(
+				"Morris",
+				2,
+				new GregorianCalendar( 1980, 0, 1 ).getTime(),
+				new Person( "Bob" ),
+				new ArrayList<Person>()
+		);
 
 		//when
 		CarDto carDto = CarMapper.INSTANCE.carToCarDto( car );
@@ -110,7 +123,13 @@ public class CarMapperTest extends MapperTestBase {
 	@Test
 	public void shouldMapAttributeWithCustomMapping() {
 		//given
-		Car car = new Car( "Morris", 2, 1980, new Person( "Bob" ), new ArrayList<Person>() );
+		Car car = new Car(
+				"Morris",
+				2,
+				new GregorianCalendar( 1980, 0, 1 ).getTime(),
+				new Person( "Bob" ),
+				new ArrayList<Person>()
+		);
 
 		//when
 		CarDto carDto = CarMapper.INSTANCE.carToCarDto( car );
@@ -136,7 +155,13 @@ public class CarMapperTest extends MapperTestBase {
 	@Test
 	public void shouldApplyConverter() {
 		//given
-		Car car = new Car( "Morris", 2, 1980, new Person( "Bob" ), new ArrayList<Person>() );
+		Car car = new Car(
+				"Morris",
+				2,
+				new GregorianCalendar( 1980, 0, 1 ).getTime(),
+				new Person( "Bob" ),
+				new ArrayList<Person>()
+		);
 
 		//when
 		CarDto carDto = CarMapper.INSTANCE.carToCarDto( car );
@@ -156,14 +181,26 @@ public class CarMapperTest extends MapperTestBase {
 
 		//then
 		assertThat( car ).isNotNull();
-		assertThat( car.getYearOfManufacture() ).isEqualTo( 1980 );
+		assertThat( car.getManufacturingDate() ).isEqualTo( new GregorianCalendar( 1980, 0, 1 ).getTime() );
 	}
 
 	@Test
 	public void shouldMapIterable() {
 		//given
-		Car car1 = new Car( "Morris", 2, 1980, new Person( "Bob" ), new ArrayList<Person>() );
+		Car car1 = new Car(
-		Car car2 = new Car( "Railton", 4, 1934, new Person( "Bill" ), new ArrayList<Person>() );
+				"Morris",
+				2,
+				new GregorianCalendar( 1980, 0, 1 ).getTime(),
+				new Person( "Bob" ),
+				new ArrayList<Person>()
+		);
+		Car car2 = new Car(
+				"Railton",
+				4,
+				new GregorianCalendar( 1934, 0, 1 ).getTime(),
+				new Person( "Bill" ),
+				new ArrayList<Person>()
+		);
 
 		//when
 		List<CarDto> dtos = CarMapper.INSTANCE.carsToCarDtos( new ArrayList<Car>( Arrays.asList( car1, car2 ) ) );
@@ -198,12 +235,12 @@ public class CarMapperTest extends MapperTestBase {
 
 		assertThat( cars.get( 0 ).getMake() ).isEqualTo( "Morris" );
 		assertThat( cars.get( 0 ).getNumberOfSeats() ).isEqualTo( 2 );
-		assertThat( cars.get( 0 ).getYearOfManufacture() ).isEqualTo( 1980 );
+		assertThat( cars.get( 0 ).getManufacturingDate() ).isEqualTo( new GregorianCalendar( 1980, 0, 1 ).getTime() );
 		assertThat( cars.get( 0 ).getDriver().getName() ).isEqualTo( "Bob" );
 
 		assertThat( cars.get( 1 ).getMake() ).isEqualTo( "Railton" );
 		assertThat( cars.get( 1 ).getNumberOfSeats() ).isEqualTo( 4 );
-		assertThat( cars.get( 1 ).getYearOfManufacture() ).isEqualTo( 1934 );
+		assertThat( cars.get( 1 ).getManufacturingDate() ).isEqualTo( new GregorianCalendar( 1934, 0, 1 ).getTime() );
 		assertThat( cars.get( 1 ).getDriver().getName() ).isEqualTo( "Bill" );
 	}
 
@@ -213,7 +250,7 @@ public class CarMapperTest extends MapperTestBase {
 		Car car = new Car(
 				"Morris",
 				2,
-				1980,
+				new GregorianCalendar( 1980, 0, 1 ).getTime(),
 				new Person( "Bob" ),
 				new ArrayList<Person>( Arrays.asList( new Person( "Alice" ), new Person( "Bill" ) ) )
 		);

processor/src/test/java/org/mapstruct/ap/test/model/Car.java

@@ -16,12 +16,13 @@
 package org.mapstruct.ap.test.model;
 
 import java.util.ArrayList;
+import java.util.Date;
 
 public class Car {
 
 	private String make;
 	private int numberOfSeats;
-	private int yearOfManufacture;
+	private Date manufacturingDate;
 	private Person driver;
 	private ArrayList<Person> passengers;
 	private int price;
@@ -30,10 +31,10 @@ public class Car {
 	public Car() {
 	}
 
-	public Car(String make, int numberOfSeats, int yearOfManufacture, Person driver, ArrayList<Person> passengers) {
+	public Car(String make, int numberOfSeats, Date manufacturingDate, Person driver, ArrayList<Person> passengers) {
 		this.make = make;
 		this.numberOfSeats = numberOfSeats;
-		this.yearOfManufacture = yearOfManufacture;
+		this.manufacturingDate = manufacturingDate;
 		this.driver = driver;
 		this.passengers = passengers;
 	}
@@ -54,12 +55,12 @@ public class Car {
 		this.numberOfSeats = numberOfSeats;
 	}
 
-	public int getYearOfManufacture() {
+	public Date getManufacturingDate() {
-		return yearOfManufacture;
+		return manufacturingDate;
 	}
 
-	public void setYearOfManufacture(int yearOfManufacture) {
+	public void setManufacturingDate(Date manufacturingDate) {
-		this.yearOfManufacture = yearOfManufacture;
+		this.manufacturingDate = manufacturingDate;
 	}
 
 	public Person getDriver() {

processor/src/test/java/org/mapstruct/ap/test/model/CarMapper.java

@@ -22,14 +22,14 @@ import org.mapstruct.Mappers;
 import org.mapstruct.Mapping;
 import org.mapstruct.Mappings;
 
-@Mapper
+@Mapper(uses = DateMapper.class)
 public interface CarMapper {
 
 	CarMapper INSTANCE = Mappers.getMapper( CarMapper.class );
 
 	@Mappings({
 			@Mapping(source = "numberOfSeats", target = "seatCount"),
-			@Mapping(source = "yearOfManufacture", target = "manufacturingYear", converter = IntToStringConverter.class)
+			@Mapping(source = "manufacturingDate", target = "manufacturingYear")
 	})
 	CarDto carToCarDto(Car car);
 

processor/src/test/java/org/mapstruct/ap/test/model/DateMapper.java

@@ -15,17 +15,22 @@
  */
 package org.mapstruct.ap.test.model;
 
-import org.mapstruct.converter.Converter;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Date;
 
-public class IntToStringConverter implements Converter<Integer, String> {
+public class DateMapper {
 
-	@Override
+	public String asString(Date date) {
-	public String from(Integer source) {
+		return date != null ? new SimpleDateFormat( "yyyy" ).format( date ) : null;
-		return source != null ? source.toString() : null;
 	}
 
-	@Override
+	public Date asDate(String date) {
-	public Integer to(String target) {
+		try {
-		return target != null ? Integer.valueOf( target ) : null;
+			return date != null ? new SimpleDateFormat( "yyyy" ).parse( date ) : null;
+		}
+		catch ( ParseException e ) {
+			throw new RuntimeException( e );
+		}
 	}
 }