#31 Providing support for bean mapping methods with several source parameters

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

@@ -0,0 +1,64 @@
+/**
+ *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  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.ap;
+
+import javax.lang.model.element.AnnotationMirror;
+import javax.lang.model.element.AnnotationValue;
+import javax.lang.model.element.Element;
+
+/**
+ * Indicates an error during annotation processing.
+ *
+ * @author Gunnar Morling
+ */
+@SuppressWarnings("serial")
+public class AnnotationProcessingException extends RuntimeException {
+
+    private final Element element;
+    private final AnnotationMirror annotationMirror;
+    private final AnnotationValue annotationValue;
+
+    public AnnotationProcessingException(String message, Element element) {
+        this( message, element, null, null );
+    }
+
+    public AnnotationProcessingException(String message, Element element, AnnotationMirror annotationMirror) {
+        this( message, element, annotationMirror, null );
+    }
+
+    public AnnotationProcessingException(String message, Element element, AnnotationMirror annotationMirror,
+                                         AnnotationValue annotationValue) {
+        super( message );
+        this.element = element;
+        this.annotationMirror = annotationMirror;
+        this.annotationValue = annotationValue;
+    }
+
+    public Element getElement() {
+        return element;
+    }
+
+    public AnnotationMirror getAnnotationMirror() {
+        return annotationMirror;
+    }
+
+    public AnnotationValue getAnnotationValue() {
+        return annotationValue;
+    }
+}

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

@@ -36,6 +36,7 @@ import javax.lang.model.element.Element;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.util.ElementKindVisitor6;
+import javax.tools.Diagnostic.Kind;
 
 import net.java.dev.hickory.prism.GeneratePrism;
 import net.java.dev.hickory.prism.GeneratePrisms;
@@ -152,7 +153,20 @@ public class MappingProcessor extends AbstractProcessor {
         Object model = null;
 
         for ( ModelElementProcessor<?, ?> processor : getProcessors() ) {
-            model = process( context, processor, mapperTypeElement, model );
+            try {
+                model = process( context, processor, mapperTypeElement, model );
+            }
+            catch ( AnnotationProcessingException e ) {
+                processingEnv.getMessager()
+                    .printMessage(
+                        Kind.ERROR,
+                        e.getMessage(),
+                        e.getElement(),
+                        e.getAnnotationMirror(),
+                        e.getAnnotationValue()
+                    );
+                break;
+            }
         }
     }
 

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

@@ -18,7 +18,10 @@
  */
 package org.mapstruct.ap.model;
 
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import org.mapstruct.ap.model.source.Method;
@@ -43,6 +46,22 @@ public class BeanMappingMethod extends MappingMethod {
         return propertyMappings;
     }
 
+    public Map<String, List<PropertyMapping>> getPropertyMappingsByParameter() {
+        Map<String, List<PropertyMapping>> mappingsByParameter = new HashMap<String, List<PropertyMapping>>();
+
+        for ( Parameter sourceParameter : getSourceParameters() ) {
+            ArrayList<PropertyMapping> mappingsOfParameter = new ArrayList<PropertyMapping>();
+            mappingsByParameter.put( sourceParameter.getName(), mappingsOfParameter );
+            for ( PropertyMapping mapping : propertyMappings ) {
+                if ( mapping.getSourceBeanName().equals( sourceParameter.getName() ) ) {
+                    mappingsOfParameter.add( mapping );
+                }
+            }
+        }
+
+        return mappingsByParameter;
+    }
+
     @Override
     public Set<Type> getImportTypes() {
         Set<Type> types = super.getImportTypes();

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

@@ -42,6 +42,16 @@ public class IterableMappingMethod extends MappingMethod {
         this.conversion = conversion;
     }
 
+    public Parameter getSourceParameter() {
+        for ( Parameter parameter : getParameters() ) {
+            if ( !parameter.isMappingTarget() ) {
+                return parameter;
+            }
+        }
+
+        throw new IllegalStateException( "Method " + this + " has no source parameter." );
+    }
+
     public MappingMethodReference getElementMappingMethod() {
         return elementMappingMethod;
     }
@@ -64,7 +74,7 @@ public class IterableMappingMethod extends MappingMethod {
     public String getLoopVariableName() {
         return Strings.getSaveVariableName(
             Introspector.decapitalize(
-                getSingleSourceParameter().getType()
+                getSourceParameter().getType()
                     .getTypeParameters()
                     .get( 0 )
                     .getName()

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

@@ -46,6 +46,16 @@ public class MapMappingMethod extends MappingMethod {
         this.valueConversion = valueConversion;
     }
 
+    public Parameter getSourceParameter() {
+        for ( Parameter parameter : getParameters() ) {
+            if ( !parameter.isMappingTarget() ) {
+                return parameter;
+            }
+        }
+
+        throw new IllegalStateException( "Method " + this + " has no source parameter." );
+    }
+
     public MappingMethodReference getKeyMappingMethod() {
         return keyMappingMethod;
     }

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

@@ -37,14 +37,12 @@ public abstract class MappingMethod extends AbstractModelElement {
     private final String name;
     private final List<Parameter> parameters;
     private final Type returnType;
-    private final Parameter singleSourceParameter;
     private final Parameter targetParameter;
 
     public MappingMethod(Method method) {
         this.name = method.getName();
         this.parameters = method.getParameters();
         this.returnType = method.getReturnType();
-        this.singleSourceParameter = method.getSingleSourceParameter();
         this.targetParameter = method.getTargetParameter();
     }
 
@@ -56,8 +54,16 @@ public abstract class MappingMethod extends AbstractModelElement {
         return parameters;
     }
 
-    public Parameter getSingleSourceParameter() {
+    public List<Parameter> getSourceParameters() {
-        return singleSourceParameter;
+        List<Parameter> sourceParameters = new ArrayList<Parameter>();
+
+        for ( Parameter parameter : parameters ) {
+            if ( !parameter.isMappingTarget() ) {
+                sourceParameters.add( parameter );
+            }
+        }
+
+        return sourceParameters;
     }
 
     public Type getResultType() {

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

@@ -31,6 +31,7 @@ import java.util.Set;
  */
 public class PropertyMapping extends AbstractModelElement {
 
+    private final String sourceBeanName;
     private final String sourceName;
     private final String sourceAccessorName;
     private final Type sourceType;
@@ -42,10 +43,11 @@ public class PropertyMapping extends AbstractModelElement {
     private final MappingMethodReference mappingMethod;
     private final TypeConversion conversion;
 
-    public PropertyMapping(String sourceName, String sourceAccessorName, Type sourceType, String targetName,
+    public PropertyMapping(String sourceBeanName, String sourceName, String sourceAccessorName, Type sourceType,
-                           String targetAccessorName, Type targetType, MappingMethodReference mappingMethod,
+                           String targetName, String targetAccessorName, Type targetType,
-                           TypeConversion conversion) {
+                           MappingMethodReference mappingMethod, TypeConversion conversion) {
 
+        this.sourceBeanName = sourceBeanName;
         this.sourceName = sourceName;
         this.sourceAccessorName = sourceAccessorName;
         this.sourceType = sourceType;
@@ -58,6 +60,10 @@ public class PropertyMapping extends AbstractModelElement {
         this.conversion = conversion;
     }
 
+    public String getSourceBeanName() {
+        return sourceBeanName;
+    }
+
     public String getSourceName() {
         return sourceName;
     }

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

@@ -22,7 +22,9 @@ import java.util.HashMap;
 import java.util.Map;
 import javax.lang.model.element.AnnotationMirror;
 import javax.lang.model.element.AnnotationValue;
+import javax.lang.model.element.Element;
 
+import org.mapstruct.ap.AnnotationProcessingException;
 import org.mapstruct.ap.MappingPrism;
 import org.mapstruct.ap.MappingsPrism;
 
@@ -34,25 +36,36 @@ import org.mapstruct.ap.MappingsPrism;
 public class Mapping {
 
     private final String sourceName;
+    private final String sourceParameterName;
+    private final String sourcePropertyName;
     private final String targetName;
     private final String dateFormat;
     private final AnnotationMirror mirror;
     private final AnnotationValue sourceAnnotationValue;
     private final AnnotationValue targetAnnotationValue;
 
-    public static Map<String, Mapping> fromMappingsPrism(MappingsPrism mappingsAnnotation) {
+    public static Map<String, Mapping> fromMappingsPrism(MappingsPrism mappingsAnnotation, Element element) {
         Map<String, Mapping> mappings = new HashMap<String, Mapping>();
 
         for ( MappingPrism mapping : mappingsAnnotation.value() ) {
-            mappings.put( mapping.source(), fromMappingPrism( mapping ) );
+            mappings.put( mapping.source(), fromMappingPrism( mapping, element ) );
         }
 
         return mappings;
     }
 
-    public static Mapping fromMappingPrism(MappingPrism mapping) {
+    public static Mapping fromMappingPrism(MappingPrism mapping, Element element) {
+        String[] sourceNameParts = getSourceNameParts(
+            mapping.source(),
+            element,
+            mapping.mirror,
+            mapping.values.source()
+        );
+
         return new Mapping(
             mapping.source(),
+            sourceNameParts != null ? sourceNameParts[0] : null,
+            sourceNameParts != null ? sourceNameParts[1] : mapping.source(),
             mapping.target(),
             mapping.dateFormat(),
             mapping.mirror,
@@ -61,9 +74,31 @@ public class Mapping {
         );
     }
 
-    private Mapping(String sourceName, String targetName, String dateFormat, AnnotationMirror mirror,
+    private static String[] getSourceNameParts(String sourceName, Element element, AnnotationMirror annotationMirror,
-                    AnnotationValue sourceAnnotationValue, AnnotationValue targetAnnotationValue) {
+                                               AnnotationValue annotationValue) {
+        if ( !sourceName.contains( "." ) ) {
+            return null;
+        }
+
+        String[] parts = sourceName.split( "\\." );
+        if ( parts.length != 2 ) {
+            throw new AnnotationProcessingException(
+                "Mapping of nested attributes not supported yet.",
+                element,
+                annotationMirror,
+                annotationValue
+            );
+        }
+
+        return parts;
+    }
+
+    private Mapping(String sourceName, String sourceParameterName, String sourcePropertyName, String targetName,
+                    String dateFormat, AnnotationMirror mirror, AnnotationValue sourceAnnotationValue,
+                    AnnotationValue targetAnnotationValue) {
         this.sourceName = sourceName;
+        this.sourceParameterName = sourceParameterName;
+        this.sourcePropertyName = sourcePropertyName;
         this.targetName = targetName.equals( "" ) ? sourceName : targetName;
         this.dateFormat = dateFormat;
         this.mirror = mirror;
@@ -71,10 +106,34 @@ public class Mapping {
         this.targetAnnotationValue = targetAnnotationValue;
     }
 
+    /**
+     * Returns the complete source name of this mapping, either a qualified (e.g. {@code parameter1.foo}) or
+     * unqualified (e.g. {@code foo}) property reference.
+     *
+     * @return The complete source name of this mapping.
+     */
     public String getSourceName() {
         return sourceName;
     }
 
+    /**
+     * Returns the unqualified name of the source property (i.e. without the parameter name if given) of this mapping.
+     *
+     * @return The unqualified name of the source property of this mapping.
+     */
+    public String getSourcePropertyName() {
+        return sourcePropertyName;
+    }
+
+    /**
+     * Returns the name of the source parameter of this mapping if the source name is qualified.
+     *
+     * @return The name of the source parameter of this mapping if given, {@code null} otherwise.
+     */
+    public String getSourceParameterName() {
+        return sourceParameterName;
+    }
+
     public String getTargetName() {
         return targetName;
     }
@@ -96,7 +155,16 @@ public class Mapping {
     }
 
     public Mapping reverse() {
-        return new Mapping( targetName, sourceName, dateFormat, mirror, sourceAnnotationValue, targetAnnotationValue );
+        return new Mapping(
+            targetName,
+            null,
+            targetName,
+            sourceName,
+            dateFormat,
+            mirror,
+            sourceAnnotationValue,
+            targetAnnotationValue
+        );
     }
 
     @Override

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

@@ -45,7 +45,6 @@ public class Method {
     private IterableMapping iterableMapping;
     private MapMapping mapMapping;
 
-    private final Parameter singleSourceParameter;
     private final Parameter targetParameter;
 
     public static Method forMethodRequiringImplementation(ExecutableElement executable, List<Parameter> parameters,
@@ -83,12 +82,10 @@ public class Method {
         this.executable = executable;
         this.parameters = parameters;
         this.returnType = returnType;
-
         this.mappings = mappings;
         this.iterableMapping = iterableMapping;
         this.mapMapping = mapMapping;
 
-        this.singleSourceParameter = determineSingleSourceParameter();
         this.targetParameter = determineTargetParameter( parameters );
     }
 
@@ -102,16 +99,6 @@ public class Method {
         return null;
     }
 
-    private Parameter determineSingleSourceParameter() {
-        for ( Parameter parameter : parameters ) {
-            if ( !parameter.isMappingTarget() ) {
-                return parameter;
-            }
-        }
-
-        throw new IllegalStateException( "Method " + this + " has no source parameter." );
-    }
-
     /**
      * Returns the mapper type declaring this method if it is not declared by
      * the mapper interface currently processed but by another mapper imported
@@ -135,6 +122,18 @@ public class Method {
         return parameters;
     }
 
+    public List<Parameter> getSourceParameters() {
+        List<Parameter> sourceParameters = new ArrayList<Parameter>();
+
+        for ( Parameter parameter : parameters ) {
+            if ( !parameter.isMappingTarget() ) {
+                sourceParameters.add( parameter );
+            }
+        }
+
+        return sourceParameters;
+    }
+
     public List<String> getParameterNames() {
         List<String> parameterNames = new ArrayList<String>( parameters.size() );
 
@@ -179,12 +178,10 @@ public class Method {
 
     public boolean reverses(Method method) {
         return
-            equals( getSingleSourceParameter().getType(), method.getResultType() )
+            getSourceParameters().size() == 1 &&
-                && equals( getResultType(), method.getSingleSourceParameter().getType() );
+                method.getSourceParameters().size() == 1 &&
-    }
+                equals( getSourceParameters().iterator().next().getType(), method.getResultType() ) &&
-
+                equals( getResultType(), method.getSourceParameters().iterator().next().getType() );
-    public Parameter getSingleSourceParameter() {
-        return singleSourceParameter;
     }
 
     public Parameter getTargetParameter() {
@@ -192,11 +189,13 @@ public class Method {
     }
 
     public boolean isIterableMapping() {
-        return getSingleSourceParameter().getType().isIterableType() && getResultType().isIterableType();
+        return getSourceParameters().size() == 1 &&
+            getSourceParameters().iterator().next().getType().isIterableType() && getResultType().isIterableType();
     }
 
     public boolean isMapMapping() {
-        return getSingleSourceParameter().getType().isMapType() && getResultType().isMapType();
+        return getSourceParameters().size() == 1 && getSourceParameters().iterator().next().getType().isMapType() &&
+            getResultType().isMapType();
     }
 
     private boolean equals(Object o1, Object o2) {
@@ -207,4 +206,24 @@ public class Method {
     public String toString() {
         return returnType + " " + getName() + "(" + Strings.join( parameters, ", " ) + ")";
     }
+
+    public Mapping getMapping(String targetPropertyName) {
+        for ( Mapping mapping : mappings.values() ) {
+            if ( mapping.getTargetName().equals( targetPropertyName ) ) {
+                return mapping;
+            }
+        }
+
+        return null;
+    }
+
+    public Parameter getSourceParameter(String sourceParameterName) {
+        for ( Parameter parameter : getSourceParameters() ) {
+            if ( parameter.getName().equals( sourceParameterName ) ) {
+                return parameter;
+            }
+        }
+
+        return null;
+    }
 }

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

@@ -181,7 +181,10 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
                         method.setMappings( reverse( reverseMappingMethod.getMappings() ) );
                     }
                 }
-                mappingMethods.add( getBeanMappingMethod( methods, method, unmappedTargetPolicy ) );
+                MappingMethod beanMappingMethod = getBeanMappingMethod( methods, method, unmappedTargetPolicy );
+                if ( beanMappingMethod != null ) {
+                    mappingMethods.add( beanMappingMethod );
+                }
             }
         }
         return mappingMethods;
@@ -210,60 +213,91 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
         return reversed;
     }
 
+    private PropertyMapping getPropertyMapping(List<Method> methods, Method method, ExecutableElement setterMethod,
+                                               Parameter parameter) {
+        String targetPropertyName = executables.getPropertyName( setterMethod );
+        Mapping mapping = method.getMapping( targetPropertyName );
+        String dateFormat = mapping != null ? mapping.getDateFormat() : null;
+        String sourcePropertyName = mapping != null ? mapping.getSourcePropertyName() : targetPropertyName;
+        TypeElement parameterElement = elementUtils.getTypeElement( parameter.getType().getCanonicalName() );
+        List<ExecutableElement> sourceGetters = Filters.getterMethodsIn(
+            elementUtils.getAllMembers( parameterElement )
+        );
+
+        for ( ExecutableElement getter : sourceGetters ) {
+            Mapping sourceMapping = method.getMappings().get( sourcePropertyName );
+            boolean mapsToOtherTarget =
+                sourceMapping != null && !sourceMapping.getTargetName().equals( targetPropertyName );
+            if ( executables.getPropertyName( getter ).equals( sourcePropertyName ) && !mapsToOtherTarget ) {
+                return getPropertyMapping(
+                    methods,
+                    method,
+                    parameter,
+                    getter,
+                    setterMethod,
+                    dateFormat
+                );
+            }
+        }
+
+        return null;
+    }
+
     private MappingMethod getBeanMappingMethod(List<Method> methods, Method method,
                                                ReportingPolicy unmappedTargetPolicy) {
         List<PropertyMapping> propertyMappings = new ArrayList<PropertyMapping>();
         Set<String> mappedTargetProperties = new HashSet<String>();
 
-        Map<String, Mapping> mappings = method.getMappings();
+        if ( !reportErrorIfMappedPropertiesDontExist( method ) ) {
+            return null;
+        }
 
         TypeElement resultTypeElement = elementUtils.getTypeElement( method.getResultType().getCanonicalName() );
-        TypeElement parameterElement = elementUtils.getTypeElement(
-            method.getSingleSourceParameter()
-                .getType()
-                .getCanonicalName()
-        );
-
-        List<ExecutableElement> sourceGetters = Filters.getterMethodsIn(
-            elementUtils.getAllMembers( parameterElement )
-        );
         List<ExecutableElement> targetSetters = Filters.setterMethodsIn(
             elementUtils.getAllMembers( resultTypeElement )
         );
 
-        Set<String> sourceProperties = executables.getPropertyNames(
+        for ( ExecutableElement setterMethod : targetSetters ) {
-            Filters.getterMethodsIn( sourceGetters )
+            String targetPropertyName = executables.getPropertyName( setterMethod );
-        );
-        Set<String> targetProperties = executables.getPropertyNames(
-            Filters.setterMethodsIn( targetSetters )
-        );
 
-        reportErrorIfMappedPropertiesDontExist( method, sourceProperties, targetProperties );
+            Mapping mapping = method.getMapping( targetPropertyName );
 
-        for ( ExecutableElement getterMethod : sourceGetters ) {
+            PropertyMapping propertyMapping = null;
-            String sourcePropertyName = executables.getPropertyName( getterMethod );
+            if ( mapping != null && mapping.getSourceParameterName() != null ) {
-            Mapping mapping = mappings.get( sourcePropertyName );
+                Parameter parameter = method.getSourceParameter( mapping.getSourceParameterName() );
-            String dateFormat = mapping != null ? mapping.getDateFormat() : null;
+                propertyMapping = getPropertyMapping( methods, method, setterMethod, parameter );
+            }
 
-            for ( ExecutableElement setterMethod : targetSetters ) {
+            if ( propertyMapping == null ) {
-                String targetPropertyName = executables.getPropertyName( setterMethod );
+                for ( Parameter sourceParameter : method.getSourceParameters() ) {
-
+                    PropertyMapping newPropertyMapping = getPropertyMapping(
-                if ( targetPropertyName.equals( mapping != null ? mapping.getTargetName() : sourcePropertyName ) ) {
-                    PropertyMapping property = getPropertyMapping(
                         methods,
                         method,
-                        getterMethod,
                         setterMethod,
-                        dateFormat
+                        sourceParameter
                     );
-
+                    if ( propertyMapping != null && newPropertyMapping != null ) {
-                    propertyMappings.add( property );
+                        messager.printMessage(
-
+                            Kind.ERROR,
-                    mappedTargetProperties.add( targetPropertyName );
+                            "Several possible source properties for target property \"" + targetPropertyName + "\".",
+                            method.getExecutable()
+                        );
+                        break;
+                    }
+                    else if ( newPropertyMapping != null ) {
+                        propertyMapping = newPropertyMapping;
+                    }
                 }
             }
+
+            if ( propertyMapping != null ) {
+                propertyMappings.add( propertyMapping );
+                mappedTargetProperties.add( targetPropertyName );
+            }
         }
 
+        Set<String> targetProperties = executables.getPropertyNames( targetSetters );
+
         reportErrorForUnmappedTargetPropertiesIfRequired(
             method,
             unmappedTargetPolicy,
@@ -303,21 +337,85 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
         return null;
     }
 
-    private void reportErrorIfMappedPropertiesDontExist(Method method, Set<String> sourceProperties,
+    private boolean hasSourceProperty(Method method, String propertyName) {
-                                                        Set<String> targetProperties) {
+        for ( Parameter parameter : method.getSourceParameters() ) {
+            if ( hasProperty( parameter, propertyName ) ) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private boolean hasProperty(Parameter parameter, String propertyName) {
+        TypeElement parameterTypeElement = elementUtils.getTypeElement( parameter.getType().getCanonicalName() );
+        List<ExecutableElement> getters = Filters.setterMethodsIn(
+            elementUtils.getAllMembers( parameterTypeElement )
+        );
+
+        return executables.getPropertyNames( getters ).contains( propertyName );
+    }
+
+    private boolean reportErrorIfMappedPropertiesDontExist(Method method) {
+        TypeElement resultTypeElement = elementUtils.getTypeElement( method.getResultType().getCanonicalName() );
+        List<ExecutableElement> targetSetters = Filters.setterMethodsIn(
+            elementUtils.getAllMembers( resultTypeElement )
+        );
+
+        Set<String> targetProperties = executables.getPropertyNames( targetSetters );
+
+        boolean foundUnmappedProperty = false;
+
         for ( Mapping mappedProperty : method.getMappings().values() ) {
-            if ( !sourceProperties.contains( mappedProperty.getSourceName() ) ) {
+            if ( mappedProperty.getSourceParameterName() != null ) {
+                Parameter sourceParameter = method.getSourceParameter( mappedProperty.getSourceParameterName() );
+
+                if ( sourceParameter == null ) {
+                    messager.printMessage(
+                        Kind.ERROR,
+                        String.format(
+                            "Method has no parameter named \"%s\".",
+                            mappedProperty.getSourceParameterName()
+                        ),
+                        method.getExecutable(),
+                        mappedProperty.getMirror(),
+                        mappedProperty.getSourceAnnotationValue()
+                    );
+                    foundUnmappedProperty = true;
+                }
+                else {
+                    if ( !hasProperty( sourceParameter, mappedProperty.getSourcePropertyName() ) ) {
+                        messager.printMessage(
+                            Kind.ERROR,
+                            String.format(
+                                "The type of parameter \"%s\" has no property named \"%s\".",
+                                mappedProperty.getSourceParameterName(),
+                                mappedProperty.getSourcePropertyName()
+                            ),
+                            method.getExecutable(),
+                            mappedProperty.getMirror(),
+                            mappedProperty.getSourceAnnotationValue()
+                        );
+                        foundUnmappedProperty = true;
+                    }
+                }
+
+            }
+            else if ( !hasSourceProperty(
+                method,
+                mappedProperty.getSourcePropertyName()
+            ) ) {
                 messager.printMessage(
                     Kind.ERROR,
                     String.format(
-                        "Unknown property \"%s\" in parameter type %s.",
+                        "No property named \"%s\" exists in source parameter(s).",
-                        mappedProperty.getSourceName(),
+                        mappedProperty.getSourceName()
-                        method.getSingleSourceParameter().getType()
                     ),
                     method.getExecutable(),
                     mappedProperty.getMirror(),
                     mappedProperty.getSourceAnnotationValue()
                 );
+                foundUnmappedProperty = true;
             }
             if ( !targetProperties.contains( mappedProperty.getTargetName() ) ) {
                 messager.printMessage(
@@ -331,12 +429,16 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
                     mappedProperty.getMirror(),
                     mappedProperty.getTargetAnnotationValue()
                 );
+                foundUnmappedProperty = true;
             }
         }
+
+        return !foundUnmappedProperty;
     }
 
-    private PropertyMapping getPropertyMapping(List<Method> methods, Method method, ExecutableElement getterMethod,
+    private PropertyMapping getPropertyMapping(List<Method> methods, Method method, Parameter parameter,
-                                               ExecutableElement setterMethod, String dateFormat) {
+                                               ExecutableElement getterMethod, ExecutableElement setterMethod,
+                                               String dateFormat) {
         Type sourceType = executables.retrieveReturnType( getterMethod );
         Type targetType = executables.retrieveSingleParameter( setterMethod ).getType();
 
@@ -345,11 +447,11 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
             sourceType,
             targetType,
             dateFormat,
-            method.getSingleSourceParameter().getName() + "."
+            parameter.getName() + "." + getterMethod.getSimpleName().toString() + "()"
-                + getterMethod.getSimpleName().toString() + "()"
         );
 
         PropertyMapping property = new PropertyMapping(
+            parameter.getName(),
             executables.getPropertyName( getterMethod ),
             getterMethod.getSimpleName().toString(),
             sourceType,
@@ -369,7 +471,7 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
     }
 
     private MappingMethod getIterableMappingMethod(List<Method> methods, Method method) {
-        Type sourceElementType = method.getSingleSourceParameter().getType().getTypeParameters().get( 0 );
+        Type sourceElementType = method.getSourceParameters().iterator().next().getType().getTypeParameters().get( 0 );
         Type targetElementType = method.getResultType().getTypeParameters().get( 0 );
 
         TypeConversion conversion = getConversion(
@@ -390,7 +492,7 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
     }
 
     private MappingMethod getMapMappingMethod(List<Method> methods, Method method) {
-        List<Type> sourceTypeParams = method.getSingleSourceParameter().getType().getTypeParameters();
+        List<Type> sourceTypeParams = method.getSourceParameters().iterator().next().getType().getTypeParameters();
         Type sourceKeyType = sourceTypeParams.get( 0 );
         Type sourceValueType = sourceTypeParams.get( 1 );
 
@@ -431,12 +533,16 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
 
     private MappingMethodReference getMappingMethodReference(Iterable<Method> methods, Type parameterType,
                                                              Type returnType) {
-        for ( Method oneMethod : methods ) {
+        for ( Method method : methods ) {
-            Parameter singleSourceParam = oneMethod.getSingleSourceParameter();
+            if ( method.getSourceParameters().size() > 1 ) {
+                continue;
+            }
+
+            Parameter singleSourceParam = method.getSourceParameters().iterator().next();
 
             if ( singleSourceParam.getType().equals( parameterType ) &&
-                oneMethod.getResultType().equals( returnType ) ) {
+                method.getResultType().equals( returnType ) ) {
-                return new MappingMethodReference( oneMethod );
+                return new MappingMethodReference( method );
             }
         }
 

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

@@ -194,15 +194,6 @@ public class MethodRetrievalProcessor implements ModelElementProcessor<Void, Lis
             return false;
         }
 
-        if ( sourceParameters.size() > 1 ) {
-            messager.printMessage(
-                Kind.ERROR,
-                "Mappings from more than one source objects are not yet supported.",
-                method
-            );
-            return false;
-        }
-
         if ( targetParameter != null && ( sourceParameters.size() + 1 != method.getParameters().size() ) ) {
             messager.printMessage(
                 Kind.ERROR,
@@ -274,11 +265,11 @@ public class MethodRetrievalProcessor implements ModelElementProcessor<Void, Lis
         MappingsPrism mappingsAnnotation = MappingsPrism.getInstanceOn( method );
 
         if ( mappingAnnotation != null ) {
-            mappings.put( mappingAnnotation.source(), Mapping.fromMappingPrism( mappingAnnotation ) );
+            mappings.put( mappingAnnotation.source(), Mapping.fromMappingPrism( mappingAnnotation, method ) );
         }
 
         if ( mappingsAnnotation != null ) {
-            mappings.putAll( Mapping.fromMappingsPrism( mappingsAnnotation ) );
+            mappings.putAll( Mapping.fromMappingsPrism( mappingsAnnotation, method ) );
         }
 
         return mappings;

processor/src/main/resources/org.mapstruct.ap.model.BeanMappingMethod.ftl

@@ -20,17 +20,29 @@
 -->
     @Override
     public ${returnType.name} ${name}(<#list parameters as param><@includeModel object=param/><#if param_has_next>, </#if></#list>) {
-        if ( ${singleSourceParameter.name} == null ) {
+        if ( <#list sourceParameters as sourceParam>${sourceParam.name} == null<#if sourceParam_has_next> && </#if></#list> ) {
             return<#if returnType.name != "void"> null</#if>;
         }
 
         <#if !existingInstanceMapping>
         ${resultType.name} ${resultName} = new ${resultType.name}();
+
+        </#if>
+
+        <#if (sourceParameters?size > 1)>
+            <#list sourceParameters as sourceParam>
+        if ( ${sourceParam.name} != null ) {
+                <#list propertyMappingsByParameter[sourceParam.name] as propertyMapping>
+                    <@includeModel object=propertyMapping targetBeanName=resultName/>
+                </#list>
+        }
+            </#list>
+        <#else>
+            <#list propertyMappingsByParameter[sourceParameters[0].name] as propertyMapping>
+                <@includeModel object=propertyMapping targetBeanName=resultName/>
+            </#list>
         </#if>
 
-        <#list propertyMappings as propertyMapping>
-            <@includeModel object=propertyMapping sourceBeanName=singleSourceParameter.name targetBeanName=resultName/>
-        </#list>
         <#if returnType.name != "void">
 
         return ${resultName};

processor/src/main/resources/org.mapstruct.ap.model.IterableMappingMethod.ftl

@@ -20,7 +20,7 @@
 -->
     @Override
     public <@includeModel object=returnType/> ${name}(<#list parameters as param><@includeModel object=param/><#if param_has_next>, </#if></#list>) {
-        if ( ${singleSourceParameter.name} == null ) {
+        if ( ${sourceParameter.name} == null ) {
             return<#if returnType.name != "void"> null</#if>;
         }
 
@@ -31,7 +31,7 @@
         <#if resultType.name == "Iterable" && resultType.packageName == "java.lang">${resultType.iterableImplementationType.name}<#else>${resultType.name}</#if><<@includeModel object=resultType.typeParameters[0]/>> ${resultName} = new <#if resultType.iterableImplementationType??>${resultType.iterableImplementationType.name}<#else>${resultType.name}</#if><<@includeModel object=resultType.typeParameters[0]/>>();
        </#if>
 
-        for ( <@includeModel object=singleSourceParameter.type.typeParameters[0]/> ${loopVariableName} : ${singleSourceParameter.name} ) {
+        for ( <@includeModel object=sourceParameter.type.typeParameters[0]/> ${loopVariableName} : ${sourceParameter.name} ) {
             <#if elementMappingMethod??>
             ${resultName}.add( <@includeModel object=elementMappingMethod input="${loopVariableName}"/> );
             <#else>

processor/src/main/resources/org.mapstruct.ap.model.MapMappingMethod.ftl

@@ -20,7 +20,7 @@
 -->
     @Override
     public <@includeModel object=returnType /> ${name}(<#list parameters as param><@includeModel object=param/><#if param_has_next>, </#if></#list>) {
-        if ( ${singleSourceParameter.name} == null ) {
+        if ( ${sourceParameter.name} == null ) {
             return<#if returnType.name != "void"> null</#if>;
         }
 
@@ -30,7 +30,7 @@
         <@includeModel object=resultType /> ${resultName} = new <#if resultType.mapImplementationType??><@includeModel object=resultType.mapImplementationType /><#else><@includeModel object=resultType /></#if>();
         </#if>
 
-        for ( Map.Entry<<#list singleSourceParameter.type.typeParameters as typeParameter><@includeModel object=typeParameter /><#if typeParameter_has_next>, </#if></#list>> ${entryVariableName} : ${singleSourceParameter.name}.entrySet() ) {
+        for ( Map.Entry<<#list sourceParameter.type.typeParameters as typeParameter><@includeModel object=typeParameter /><#if typeParameter_has_next>, </#if></#list>> ${entryVariableName} : ${sourceParameter.name}.entrySet() ) {
 
         <#-- key -->
         <#if keyMappingMethod??>

processor/src/main/resources/org.mapstruct.ap.model.PropertyMapping.ftl

@@ -20,11 +20,11 @@
 -->
         <#-- a) invoke mapping method -->
         <#if mappingMethod??>
-        ${ext.targetBeanName}.${targetAccessorName}( <@includeModel object=mappingMethod input="${ext.sourceBeanName}.${sourceAccessorName}()"/> );
+        ${ext.targetBeanName}.${targetAccessorName}( <@includeModel object=mappingMethod input="${sourceBeanName}.${sourceAccessorName}()"/> );
         <#-- b) simple conversion -->
         <#elseif conversion??>
             <#if sourceType.primitive == false>
-        if ( ${ext.sourceBeanName}.${sourceAccessorName}() != null ) {
+        if ( ${sourceBeanName}.${sourceAccessorName}() != null ) {
              <@applyConversion targetBeanName=ext.targetBeanName targetAccessorName=targetAccessorName conversion=conversion/>
         }
             <#else>
@@ -33,11 +33,11 @@
         <#-- c) simply set -->
         <#else>
             <#if targetType.collectionType == true>
-        if ( ${ext.sourceBeanName}.${sourceAccessorName}() != null ) {
+        if ( ${sourceBeanName}.${sourceAccessorName}() != null ) {
-            ${ext.targetBeanName}.${targetAccessorName}( new <#if targetType.collectionImplementationType??>${targetType.collectionImplementationType.name}<#else>${targetType.name}</#if><#if targetType.elementType??><${targetType.elementType.name}></#if>( ${ext.sourceBeanName}.${sourceAccessorName}() ) );
+            ${ext.targetBeanName}.${targetAccessorName}( new <#if targetType.collectionImplementationType??>${targetType.collectionImplementationType.name}<#else>${targetType.name}</#if><#if targetType.elementType??><${targetType.elementType.name}></#if>( ${sourceBeanName}.${sourceAccessorName}() ) );
         }
             <#else>
-        ${ext.targetBeanName}.${targetAccessorName}( ${ext.sourceBeanName}.${sourceAccessorName}() );
+        ${ext.targetBeanName}.${targetAccessorName}( ${sourceBeanName}.${sourceAccessorName}() );
             </#if>
         </#if>
 <#macro applyConversion targetBeanName targetAccessorName conversion>

processor/src/test/java/org/mapstruct/ap/test/erroneous/attributereference/AnotherTarget.java

@@ -20,13 +20,13 @@ package org.mapstruct.ap.test.erroneous.attributereference;
 
 public class AnotherTarget {
 
-    private int foo;
+    private int bar;
 
-    public int getFoo() {
+    public int getBar() {
-        return foo;
+        return bar;
     }
 
-    public void setFoo(int foo) {
+    public void setBar(int bar) {
-        this.foo = foo;
+        this.bar = bar;
     }
 }

processor/src/test/java/org/mapstruct/ap/test/erroneous/attributereference/ErroneousMapper.java

@@ -20,13 +20,18 @@ package org.mapstruct.ap.test.erroneous.attributereference;
 
 import org.mapstruct.Mapper;
 import org.mapstruct.Mapping;
+import org.mapstruct.Mappings;
 
 @Mapper
 public interface ErroneousMapper {
 
-    @Mapping(source = "foo", target = "bar")
+    @Mappings({
+        @Mapping(source = "bar", target = "foo"),
+        @Mapping(source = "source1.foo", target = "foo"),
+        @Mapping(source = "foo", target = "bar"),
+        @Mapping(source = "source.foobar", target = "foo")
+    })
     Target sourceToTarget(Source source);
 
-    @Mapping(source = "bar", target = "foo")
     AnotherTarget sourceToAnotherTarget(Source source);
 }

processor/src/test/java/org/mapstruct/ap/test/erroneous/attributereference/ErroneousMappingsTest.java

@@ -43,16 +43,24 @@ public class ErroneousMappingsTest extends MapperTestBase {
         diagnostics = {
             @Diagnostic(type = ErroneousMapper.class,
                 kind = Kind.ERROR,
-                line = 27,
+                line = 29,
-                messageRegExp = "Unknown property \"bar\" in return type"),
+                messageRegExp = "No property named \"bar\" exists in source parameter\\(s\\)"),
-            @Diagnostic(type = ErroneousMapper.class,
-                kind = Kind.WARNING,
-                line = 28,
-                messageRegExp = "Unmapped target property: \"foo\""),
             @Diagnostic(type = ErroneousMapper.class,
                 kind = Kind.ERROR,
                 line = 30,
-                messageRegExp = "Unknown property \"bar\" in parameter type")
+                messageRegExp = "Method has no parameter named \"source1\""),
+            @Diagnostic(type = ErroneousMapper.class,
+                kind = Kind.ERROR,
+                line = 31,
+                messageRegExp = "Unknown property \"bar\" in return type"),
+            @Diagnostic(type = ErroneousMapper.class,
+                kind = Kind.ERROR,
+                line = 32,
+                messageRegExp = "The type of parameter \"source\" has no property named \"foobar\""),
+            @Diagnostic(type = ErroneousMapper.class,
+                kind = Kind.WARNING,
+                line = 36,
+                messageRegExp = "Unmapped target property: \"bar\""),
         }
     )
     public void shouldFailToGenerateMappings() {

processor/src/test/java/org/mapstruct/ap/test/severalsources/Address.java

@@ -0,0 +1,66 @@
+/**
+ *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  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.ap.test.severalsources;
+
+public class Address {
+
+    private String street;
+    private int zipCode;
+    private int houseNo;
+    private String description;
+
+    public Address(String street, int zipCode, int houseNo, String description) {
+        this.street = street;
+        this.zipCode = zipCode;
+        this.houseNo = houseNo;
+        this.description = description;
+    }
+
+    public String getStreet() {
+        return street;
+    }
+
+    public void setStreet(String street) {
+        this.street = street;
+    }
+
+    public int getZipCode() {
+        return zipCode;
+    }
+
+    public void setZipCode(int zipCode) {
+        this.zipCode = zipCode;
+    }
+
+    public int getHouseNo() {
+        return houseNo;
+    }
+
+    public void setHouseNo(int houseNo) {
+        this.houseNo = houseNo;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/severalsources/DeliveryAddress.java

@@ -0,0 +1,101 @@
+/**
+ *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  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.ap.test.severalsources;
+
+public class DeliveryAddress {
+
+    private String firstName;
+    private String lastName;
+    private int height;
+    private String street;
+    private int zipCode;
+    private int houseNumber;
+    private String description;
+
+    public DeliveryAddress() {
+    }
+
+    public DeliveryAddress(String firstName, String lastName, int height, String street, int zipCode, int houseNumber,
+                           String description) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.height = height;
+        this.street = street;
+        this.zipCode = zipCode;
+        this.houseNumber = houseNumber;
+        this.description = description;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public int getHeight() {
+        return height;
+    }
+
+    public void setHeight(int height) {
+        this.height = height;
+    }
+
+    public String getStreet() {
+        return street;
+    }
+
+    public void setStreet(String street) {
+        this.street = street;
+    }
+
+    public int getZipCode() {
+        return zipCode;
+    }
+
+    public void setZipCode(int zipCode) {
+        this.zipCode = zipCode;
+    }
+
+    public int getHouseNumber() {
+        return houseNumber;
+    }
+
+    public void setHouseNumber(int houseNumber) {
+        this.houseNumber = houseNumber;
+    }
+
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/severalsources/ErroneousSourceTargetMapper.java

@@ -0,0 +1,30 @@
+/**
+ *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  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.ap.test.severalsources;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mappers;
+
+@Mapper
+public interface ErroneousSourceTargetMapper {
+
+    ErroneousSourceTargetMapper INSTANCE = Mappers.getMapper( ErroneousSourceTargetMapper.class );
+
+    DeliveryAddress addressAndAddressToDeliveryAddress(Address address1, Address address2);
+}

processor/src/test/java/org/mapstruct/ap/test/severalsources/Person.java

@@ -0,0 +1,66 @@
+/**
+ *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  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.ap.test.severalsources;
+
+public class Person {
+
+    private String firstName;
+    private String lastName;
+    private int height;
+    private String description;
+
+    public Person(String firstName, String lastName, int height, String description) {
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.height = height;
+        this.description = description;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public int getHeight() {
+        return height;
+    }
+
+    public void setHeight(int height) {
+        this.height = height;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/severalsources/SeveralSourceParametersTest.java

@@ -0,0 +1,112 @@
+/**
+ *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  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.ap.test.severalsources;
+
+import javax.tools.Diagnostic.Kind;
+
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.MapperTestBase;
+import org.mapstruct.ap.testutil.WithClasses;
+import org.mapstruct.ap.testutil.compilation.annotation.CompilationResult;
+import org.mapstruct.ap.testutil.compilation.annotation.Diagnostic;
+import org.mapstruct.ap.testutil.compilation.annotation.ExpectedCompilationOutcome;
+import org.mapstruct.ap.testutil.compilation.annotation.ProcessorOption;
+import org.testng.annotations.Test;
+
+import static org.fest.assertions.Assertions.assertThat;
+
+/**
+ * Test for propagation of attribute without setter in source and getter in
+ * target.
+ *
+ * @author Gunnar Morling
+ */
+@IssueKey("31")
+public class SeveralSourceParametersTest extends MapperTestBase {
+
+    @Test
+    @WithClasses({ Person.class, Address.class, DeliveryAddress.class, SourceTargetMapper.class })
+    public void shouldMapSeveralSourceAttributesToCombinedTarget() {
+        Person person = new Person( "Bob", "Garner", 181, "An actor" );
+        Address address = new Address( "Main street", 12345, 42, "His address" );
+
+        DeliveryAddress deliveryAddress = SourceTargetMapper.INSTANCE
+            .personAndAddressToDeliveryAddress( person, address );
+
+        assertThat( deliveryAddress ).isNotNull();
+        assertThat( deliveryAddress.getLastName() ).isEqualTo( "Garner" );
+        assertThat( deliveryAddress.getZipCode() ).isEqualTo( 12345 );
+        assertThat( deliveryAddress.getHouseNumber() ).isEqualTo( 42 );
+        assertThat( deliveryAddress.getDescription() ).isEqualTo( "An actor" );
+    }
+
+    @Test
+    @WithClasses({ Person.class, Address.class, DeliveryAddress.class, SourceTargetMapper.class })
+    public void shouldMapSeveralSourceAttributesToCombinedTargetWithTargetParameter() {
+        Person person = new Person( "Bob", "Garner", 181, "An actor" );
+        Address address = new Address( "Main street", 12345, 42, "His address" );
+
+        DeliveryAddress deliveryAddress = new DeliveryAddress();
+        SourceTargetMapper.INSTANCE.personAndAddressToDeliveryAddress( person, address, deliveryAddress );
+
+        assertThat( deliveryAddress.getLastName() ).isEqualTo( "Garner" );
+        assertThat( deliveryAddress.getZipCode() ).isEqualTo( 12345 );
+        assertThat( deliveryAddress.getHouseNumber() ).isEqualTo( 42 );
+        assertThat( deliveryAddress.getDescription() ).isEqualTo( "An actor" );
+    }
+
+    @Test
+    @WithClasses({ Person.class, Address.class, DeliveryAddress.class, SourceTargetMapper.class })
+    public void shouldSetAttributesFromNonNullParameters() {
+        Person person = new Person( "Bob", "Garner", 181, "An actor" );
+
+        DeliveryAddress deliveryAddress = SourceTargetMapper.INSTANCE
+            .personAndAddressToDeliveryAddress( person, null );
+
+        assertThat( deliveryAddress ).isNotNull();
+        assertThat( deliveryAddress.getLastName() ).isEqualTo( "Garner" );
+        assertThat( deliveryAddress.getDescription() ).isEqualTo( "An actor" );
+        assertThat( deliveryAddress.getHouseNumber() ).isEqualTo( 0 );
+        assertThat( deliveryAddress.getStreet() ).isNull();
+    }
+
+    @Test
+    @WithClasses({ Person.class, Address.class, DeliveryAddress.class, SourceTargetMapper.class })
+    public void shouldReturnNullIfAllParametersAreNull() {
+        DeliveryAddress deliveryAddress = SourceTargetMapper.INSTANCE
+            .personAndAddressToDeliveryAddress( null, null );
+
+        assertThat( deliveryAddress ).isNull();
+    }
+
+    @Test
+    @WithClasses({ ErroneousSourceTargetMapper.class, Address.class, DeliveryAddress.class })
+    @ProcessorOption(name = "unmappedTargetPolicy", value = "IGNORE")
+    @ExpectedCompilationOutcome(
+        value = CompilationResult.FAILED,
+        diagnostics = {
+            @Diagnostic(type = ErroneousSourceTargetMapper.class,
+                kind = Kind.ERROR,
+                line = 29,
+                messageRegExp = "Several possible source properties for target property \"street\".")
+        }
+    )
+    public void shouldFailToGenerateMappingsForAmbigiousSourceProperty() {
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/severalsources/SourceTargetMapper.java

@@ -0,0 +1,44 @@
+/**
+ *  Copyright 2012-2013 Gunnar Morling (http://www.gunnarmorling.de/)
+ *  and/or other contributors as indicated by the @authors tag. See the
+ *  copyright.txt file in the distribution for a full listing of all
+ *  contributors.
+ *
+ *  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.ap.test.severalsources;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mappers;
+import org.mapstruct.Mapping;
+import org.mapstruct.MappingTarget;
+import org.mapstruct.Mappings;
+
+@Mapper
+public interface SourceTargetMapper {
+
+    SourceTargetMapper INSTANCE = Mappers.getMapper( SourceTargetMapper.class );
+
+    @Mappings({
+        @Mapping(source = "houseNo", target = "houseNumber"),
+        @Mapping(source = "person.description", target = "description")
+    })
+    DeliveryAddress personAndAddressToDeliveryAddress(Person person, Address address);
+
+    @Mappings({
+        @Mapping(source = "houseNo", target = "houseNumber"),
+        @Mapping(source = "person.description", target = "description")
+    })
+    void personAndAddressToDeliveryAddress(Person person, Address address,
+                                           @MappingTarget DeliveryAddress deliveryAddress);
+}

processor/src/test/java/org/mapstruct/ap/testutil/compilation/model/DiagnosticDescriptor.java

@@ -167,8 +167,8 @@ public class DiagnosticDescriptor {
 
     @Override
     public String toString() {
-        String sourceFileName = this.sourceFileName
+        String fileName = sourceFileName != null ?
-            .substring( this.sourceFileName.lastIndexOf( File.separatorChar ) + 1 );
+            sourceFileName.substring( this.sourceFileName.lastIndexOf( File.separatorChar ) + 1 ) : null;
-        return "DiagnosticDescriptor: " + kind + " " + sourceFileName + ":" + line + " " + message;
+        return "DiagnosticDescriptor: " + kind + " " + fileName + ":" + line + " " + message;
     }
 }