#203 Move .ftl files into subdirectories representing the package path

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

@@ -152,6 +152,6 @@ public class Decorator extends GeneratedType {
 
     @Override
     protected String getTemplateName() {
-        return GeneratedType.class.getName() + ".ftl";
+        return getTemplateNameForClass( GeneratedType.class );
     }
 }

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

@@ -160,6 +160,6 @@ public class Mapper extends GeneratedType {
 
     @Override
     protected String getTemplateName() {
-        return GeneratedType.class.getName() + ".ftl";
+        return getTemplateNameForClass( GeneratedType.class );
     }
 }

processor/src/main/java/org/mapstruct/ap/internal/model/VirtualMappingMethod.java

@@ -31,15 +31,13 @@ import org.mapstruct.ap.internal.model.source.builtin.BuiltInMethod;
  */
 public class VirtualMappingMethod extends MappingMethod {
 
-    private static final String BUILTIN_METHOD_TEMPLATE_PREFIX = "org.mapstruct.ap.internal.model.builtin.";
-
     private final String templateName;
     private final Set<Type> importTypes;
 
     public VirtualMappingMethod(BuiltInMethod method) {
         super( method );
         this.importTypes = method.getImportTypes();
-        this.templateName = BUILTIN_METHOD_TEMPLATE_PREFIX + method.getClass().getSimpleName() + ".ftl";
+        this.templateName = getTemplateNameForClass( method.getClass() );
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/internal/writer/FreeMarkerWritable.java

@@ -33,13 +33,24 @@ public abstract class FreeMarkerWritable implements Writable {
     }
 
     /**
-     * Returns the name of the template to be used for a specific writable type. By default, the fully-qualified class
+     * Returns the name of the template to be used for a specific writable type. By default,
-     * name of the given model element type, appended with the extension {@code *.ftl} is used as template file name,
+     * {@link #getTemplateNameForClass(Class)} is called with {@code getClass()}, but this can be customized by
-     * but this can be customized by overriding this method if required.
+     * overriding this method if required.
      *
      * @return the name of the template. Must not be {@code null}.
      */
     protected String getTemplateName() {
-        return getClass().getName() + ".ftl";
+        return getTemplateNameForClass( getClass() );
+    }
+
+    /**
+     * Returns the name of the template to be used for a specific writable type. By default, the package directory and
+     * the class name of the given model element type, appended with the extension {@code *.ftl} is used as template
+     * file name.
+     *
+     * @return the name of the template. Must not be {@code null}.
+     */
+    protected String getTemplateNameForClass(Class<?> clazz) {
+        return clazz.getName().replace( '.', '/' ) + ".ftl";
     }
 }