#265 adding imports to the Mapper to make expressions more easy.

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

@@ -42,6 +42,15 @@ public @interface Mapper {
      */
     Class<?>[] uses() default { };
 
+    /**
+     * Additional types for which an import statement is to be added to the generated mapper implementation class.
+     * This allows to refer to those types from within mapping expressions given via {@link #expression()} using
+     * their simple name rather than their fully-qualified name.
+     *
+     * @return classes to add in the imports of the generated implementation.
+     */
+    Class<?>[] imports() default { };
+
     /**
      * How unmapped properties of the target type of a mapping should be
      * reported. The method overrides an unmappedTargetPolicy set in a central

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

@@ -20,10 +20,10 @@ package org.mapstruct.ap.model;
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.TreeSet;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.util.Elements;
-
 import org.mapstruct.ap.model.common.Accessibility;
 import org.mapstruct.ap.model.common.ModelElement;
 import org.mapstruct.ap.model.common.Type;
@@ -51,7 +51,8 @@ public class Decorator extends GeneratedType {
             methods,
             fields,
             suppressGeneratorTimestamp,
-            accessibility
+            accessibility,
+            new TreeSet<Type>()
         );
     }
 

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

@@ -45,6 +45,7 @@ public abstract class GeneratedType extends ModelElement {
     private final List<Annotation> annotations;
     private final List<MappingMethod> methods;
     private final List<? extends ModelElement> fields;
+    private final SortedSet<Type> extraImportedTypes;
 
     private final boolean suppressGeneratorTimestamp;
     private final Accessibility accessibility;
@@ -58,11 +59,14 @@ public abstract class GeneratedType extends ModelElement {
                             String interfaceName,
                             List<MappingMethod> methods,
                             List<? extends ModelElement> fields,
-                            boolean suppressGeneratorTimestamp, Accessibility accessibility) {
+                            boolean suppressGeneratorTimestamp,
+                            Accessibility accessibility,
+                            SortedSet<Type> extraImportedTypes) {
         this.packageName = packageName;
         this.name = name;
         this.superClassName = superClassName;
         this.interfaceName = interfaceName;
+        this.extraImportedTypes = extraImportedTypes;
 
         this.annotations = new ArrayList<Annotation>();
         this.methods = methods;
@@ -135,6 +139,10 @@ public abstract class GeneratedType extends ModelElement {
             addWithDependents( importedTypes, annotation.getType() );
         }
 
+        for ( Type extraImport : extraImportedTypes ) {
+            addWithDependents( importedTypes, extraImport );
+        }
+
         return importedTypes;
     }
 

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

@@ -19,11 +19,12 @@
 package org.mapstruct.ap.model;
 
 import java.util.List;
+import java.util.SortedSet;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.util.Elements;
-
 import org.mapstruct.ap.model.common.Accessibility;
+import org.mapstruct.ap.model.common.Type;
 import org.mapstruct.ap.model.common.TypeFactory;
 
 /**
@@ -40,10 +41,11 @@ public class Mapper extends GeneratedType {
     private final List<MapperReference> referencedMappers;
     private final Decorator decorator;
 
+    //CHECKSTYLE:OFF
     private Mapper(TypeFactory typeFactory, String packageName, String name, String superClassName,
-                   String interfaceName,
+                   String interfaceName, List<MappingMethod> methods, boolean suppressGeneratorTimestamp,
-                   List<MappingMethod> methods, boolean suppressGeneratorTimestamp, Accessibility accessibility,
+                   Accessibility accessibility, List<MapperReference> referencedMappers, Decorator decorator,
-                   List<MapperReference> referencedMappers, Decorator decorator) {
+                   SortedSet<Type> extraImportedTypes ) {
 
         super(
             typeFactory,
@@ -54,7 +56,8 @@ public class Mapper extends GeneratedType {
             methods,
             referencedMappers,
             suppressGeneratorTimestamp,
-            accessibility
+            accessibility,
+            extraImportedTypes
         );
 
         this.referencedMappers = referencedMappers;
@@ -67,6 +70,7 @@ public class Mapper extends GeneratedType {
         private TypeElement element;
         private List<MappingMethod> mappingMethods;
         private List<MapperReference> mapperReferences;
+        private SortedSet<Type> extraImportedTypes;
 
         private Elements elementUtils;
         private boolean suppressGeneratorTimestamp;
@@ -107,6 +111,11 @@ public class Mapper extends GeneratedType {
             return this;
         }
 
+        public Builder extraImports(SortedSet<Type> extraImportedTypes) {
+            this.extraImportedTypes = extraImportedTypes;
+            return this;
+        }
+
         public Mapper build() {
             String implementationName = element.getSimpleName()
                 + ( decorator == null ? IMPLEMENTATION_SUFFIX : DECORATED_IMPLEMENTATION_SUFFIX );
@@ -121,7 +130,8 @@ public class Mapper extends GeneratedType {
                 suppressGeneratorTimestamp,
                 Accessibility.fromModifiers( element.getModifiers() ),
                 mapperReferences,
-                decorator
+                decorator,
+                extraImportedTypes
             );
         }
     }

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

@@ -26,6 +26,8 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.SortedSet;
+import java.util.TreeSet;
 import javax.annotation.processing.Messager;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
@@ -132,6 +134,7 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Sourc
             .decorator( getDecorator( element, methods ) )
             .typeFactory( typeFactory )
             .elementUtils( elementUtils )
+            .extraImports( getExtraImports( element ) )
             .build();
 
         return mapper;
@@ -263,6 +266,20 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Sourc
         return mapperReferences;
     }
 
+    private SortedSet<Type> getExtraImports(TypeElement element) {
+
+        SortedSet<Type> extraImports = new TreeSet<Type>();
+
+        MapperConfig mapperPrism = MapperConfig.getInstanceOn( element );
+
+        for ( TypeMirror extraImport : mapperPrism.imports() ) {
+            Type type = typeFactory.getType( extraImport );
+            extraImports.add( type );
+        }
+
+        return extraImports;
+    }
+
     private List<MappingMethod> getMappingMethods(List<MapperReference> mapperReferences, List<SourceMethod> methods,
                                                   TypeElement element) {
         List<MappingMethod> mappingMethods = new ArrayList<MappingMethod>();

processor/src/main/java/org/mapstruct/ap/util/MapperConfig.java

@@ -78,6 +78,10 @@ public class MapperConfig {
         return new ArrayList<TypeMirror>( uses );
     }
 
+    public List<TypeMirror> imports() {
+        return mapperPrism.imports();
+    }
+
     public String unmappedTargetPolicy() {
         if ( !ReportingPolicy.valueOf( mapperPrism.unmappedTargetPolicy() ).equals( ReportingPolicy.DEFAULT ) ) {
             // it is not the default configuration

processor/src/test/java/org/mapstruct/ap/test/source/expressions/java/JavaExpressionTest.java

@@ -18,6 +18,7 @@
  */
 package org.mapstruct.ap.test.source.expressions.java;
 
+import org.mapstruct.ap.test.source.expressions.java.mapper.TimeAndFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;

processor/src/test/java/org/mapstruct/ap/test/source/expressions/java/SourceTargetMapper.java

@@ -18,6 +18,7 @@
  */
 package org.mapstruct.ap.test.source.expressions.java;
 
+import org.mapstruct.ap.test.source.expressions.java.mapper.TimeAndFormat;
 import org.mapstruct.Mapper;
 import org.mapstruct.Mapping;
 import org.mapstruct.MappingTarget;
@@ -27,22 +28,20 @@ import org.mapstruct.factory.Mappers;
 /**
  * @author Sjaak Derksen
  */
-@Mapper
+@Mapper( imports = TimeAndFormat.class )
 public interface SourceTargetMapper {
 
 
     SourceTargetMapper INSTANCE = Mappers.getMapper( SourceTargetMapper.class );
 
     @Mappings( {
-        @Mapping( target = "timeAndFormat", expression = "java( new org.mapstruct.ap.test.source.expressions.java."
+        @Mapping( target = "timeAndFormat", expression = "java( new TimeAndFormat( s.getTime(), s.getFormat() ))" ),
-                + "TimeAndFormat( s.getTime(), s.getFormat() ))" ),
         @Mapping( target = "anotherProp", ignore = true )
     } )
     Target sourceToTarget( Source s );
 
     @Mappings( {
-        @Mapping( target = "timeAndFormat", expression = "java( new org.mapstruct.ap.test.source.expressions.java."
+        @Mapping( target = "timeAndFormat",  expression = "java( new TimeAndFormat( s.getTime(), s.getFormat() ))"),
-                + "TimeAndFormat( s.getTime(), s.getFormat() ))" ),
         @Mapping( target = "anotherProp", ignore = true )
     } )
     Target sourceToTargetWithMappingTarget(Source s, @MappingTarget Target t);

processor/src/test/java/org/mapstruct/ap/test/source/expressions/java/SourceTargetMapperSeveralSources.java

@@ -21,20 +21,19 @@ package org.mapstruct.ap.test.source.expressions.java;
 import org.mapstruct.Mapper;
 import org.mapstruct.Mapping;
 import org.mapstruct.Mappings;
+import org.mapstruct.ap.test.source.expressions.java.mapper.TimeAndFormat;
 import org.mapstruct.factory.Mappers;
 
 /**
  * @author Sjaak Derksen
  */
-@Mapper
+@Mapper( imports = TimeAndFormat.class )
 public interface SourceTargetMapperSeveralSources {
 
-
     SourceTargetMapperSeveralSources INSTANCE = Mappers.getMapper( SourceTargetMapperSeveralSources.class );
 
     @Mappings( {
-        @Mapping( target = "timeAndFormat", expression = "java( new org.mapstruct.ap.test.source.expressions.java."
+        @Mapping( target = "timeAndFormat", expression = "java( new TimeAndFormat( s.getTime(), s.getFormat() ))" ),
-                + "TimeAndFormat( s.getTime(), s.getFormat() ))" ),
         @Mapping( source = "anotherProp", target = "anotherProp" )
     } )
     Target sourceToTarget( Source s, Source2 s1 );

processor/src/test/java/org/mapstruct/ap/test/source/expressions/java/Target.java

@@ -18,6 +18,8 @@
  */
 package org.mapstruct.ap.test.source.expressions.java;
 
+import org.mapstruct.ap.test.source.expressions.java.mapper.TimeAndFormat;
+
 /**
  * @author Sjaak Derksen
  */

processor/src/test/java/org/mapstruct/ap/test/source/expressions/java/mapper/TimeAndFormat.java

@@ -16,7 +16,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.mapstruct.ap.test.source.expressions.java;
+package org.mapstruct.ap.test.source.expressions.java.mapper;
 
 import java.util.Date;