#1478 Use source property name for the adder iterator

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

@@ -470,6 +470,7 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
                         .sourceMethod( method )
                         .targetProperty( targetProperty )
                         .targetPropertyName( mapping.getTargetName() )
+                        .sourcePropertyName( mapping.getSourceName() )
                         .sourceReference( sourceRef )
                         .selectionParameters( mapping.getSelectionParameters() )
                         .formattingParameters( mapping.getFormattingParameters() )

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

@@ -105,6 +105,7 @@ public class PropertyMapping extends ModelElement {
         protected Type targetType;
         protected Accessor targetReadAccessor;
         protected String targetPropertyName;
+        protected String sourcePropertyName;
 
         protected List<String> dependsOn;
         protected Set<String> existingVariableNames;
@@ -171,6 +172,11 @@ public class PropertyMapping extends ModelElement {
             return (T) this;
         }
 
+        public T sourcePropertyName(String sourcePropertyName) {
+            this.sourcePropertyName = sourcePropertyName;
+            return (T) this;
+        }
+
         public T dependsOn(List<String> dependsOn) {
             this.dependsOn = dependsOn;
             return (T) this;
@@ -468,12 +474,13 @@ public class PropertyMapping extends ModelElement {
 
             Assignment result = rightHandSide;
 
+            String adderIteratorName = sourcePropertyName == null ? targetPropertyName : sourcePropertyName;
             if ( result.getSourceType().isCollectionType() ) {
-                result = new AdderWrapper( result, method.getThrownTypes(), isFieldAssignment(), targetPropertyName );
+                result = new AdderWrapper( result, method.getThrownTypes(), isFieldAssignment(), adderIteratorName );
             }
             else if ( result.getSourceType().isStreamType() ) {
                 result = new StreamAdderWrapper(
-                    result, method.getThrownTypes(), isFieldAssignment(), targetPropertyName );
+                    result, method.getThrownTypes(), isFieldAssignment(), adderIteratorName );
             }
             else {
                 // Possibly adding null to a target collection. So should be surrounded by an null check.

processor/src/main/java/org/mapstruct/ap/internal/model/assignment/AdderWrapper.java

@@ -30,10 +30,10 @@ public class AdderWrapper extends AssignmentWrapper {
     public AdderWrapper( Assignment rhs,
                          List<Type> thrownTypesToExclude,
                          boolean fieldAssignment,
-                         String targetPropertyName ) {
+                         String adderIteratorName ) {
         super( rhs, fieldAssignment );
         this.thrownTypesToExclude = thrownTypesToExclude;
-        String desiredName = Nouns.singularize( targetPropertyName );
+        String desiredName = Nouns.singularize( adderIteratorName );
         rhs.setSourceLocalVarName( rhs.createLocalVarName( desiredName ) );
         adderType = first( getSourceType().determineTypeArguments( Collection.class ) );
     }

processor/src/test/java/org/mapstruct/ap/test/collection/adder/AdderTest.java

@@ -25,12 +25,14 @@ import org.mapstruct.ap.test.collection.adder._target.TargetDali;
 import org.mapstruct.ap.test.collection.adder._target.TargetHuman;
 import org.mapstruct.ap.test.collection.adder._target.TargetOnlyGetter;
 import org.mapstruct.ap.test.collection.adder._target.TargetViaTargetType;
+import org.mapstruct.ap.test.collection.adder._target.TargetWithAnimals;
 import org.mapstruct.ap.test.collection.adder._target.TargetWithoutSetter;
 import org.mapstruct.ap.test.collection.adder.source.Foo;
 import org.mapstruct.ap.test.collection.adder.source.SingleElementSource;
 import org.mapstruct.ap.test.collection.adder.source.Source;
 import org.mapstruct.ap.test.collection.adder.source.Source2;
 import org.mapstruct.ap.test.collection.adder.source.SourceTeeth;
+import org.mapstruct.ap.test.collection.adder.source.SourceWithPets;
 import org.mapstruct.ap.testutil.IssueKey;
 import org.mapstruct.ap.testutil.WithClasses;
 import org.mapstruct.ap.testutil.runner.AnnotationProcessorTestRunner;
@@ -42,15 +44,18 @@ import org.mapstruct.ap.testutil.runner.GeneratedSource;
 @WithClasses({
     Source.class,
     SourceTeeth.class,
+    SourceWithPets.class,
     Target.class,
     TargetDali.class,
     TargetHuman.class,
     TargetOnlyGetter.class,
     TargetViaTargetType.class,
     TargetWithoutSetter.class,
+    TargetWithAnimals.class,
     SourceTargetMapper.class,
     SourceTargetMapperStrategyDefault.class,
     SourceTargetMapperStrategySetterPreferred.class,
+    SourceTargetMapperWithDifferentProperties.class,
     SingleElementSource.class,
     PetMapper.class,
     TeethMapper.class,
@@ -255,4 +260,17 @@ public class AdderTest {
         assertThat( target ).isNotNull();
         assertThat( target.getAttributes().size() ).isEqualTo( 1 );
     }
+
+    @IssueKey("1478")
+    @Test
+    public void useIterationNameFromSource() {
+        generatedSource.addComparisonToFixtureFor( SourceTargetMapperWithDifferentProperties.class );
+
+        SourceWithPets source = new SourceWithPets();
+        source.setPets( Arrays.asList( "dog", "cat" ) );
+
+        TargetWithAnimals target = SourceTargetMapperWithDifferentProperties.INSTANCE.map( source );
+
+        assertThat( target.getAnimals() ).containsExactly( "dog", "cat" );
+    }
 }

processor/src/test/java/org/mapstruct/ap/test/collection/adder/SourceTargetMapperWithDifferentProperties.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.collection.adder;
+
+import org.mapstruct.CollectionMappingStrategy;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.ap.test.collection.adder._target.TargetWithAnimals;
+import org.mapstruct.ap.test.collection.adder.source.SourceWithPets;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Filip Hrisafov
+ */
+@Mapper(collectionMappingStrategy = CollectionMappingStrategy.ADDER_PREFERRED)
+public interface SourceTargetMapperWithDifferentProperties {
+
+    SourceTargetMapperWithDifferentProperties INSTANCE =
+        Mappers.getMapper( SourceTargetMapperWithDifferentProperties.class );
+
+    @Mapping(target = "animals", source = "pets")
+    TargetWithAnimals map(SourceWithPets source);
+}

processor/src/test/java/org/mapstruct/ap/test/collection/adder/_target/TargetWithAnimals.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.collection.adder._target;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class TargetWithAnimals {
+
+    private List<String> animals = new ArrayList<String>();
+
+    public List<String> getAnimals() {
+        return animals;
+    }
+
+    public void setAnimals(List<String> animals) {
+        this.animals = animals;
+    }
+
+    public void addAnimal(String animal) {
+        animals.add( animal );
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/collection/adder/source/SourceWithPets.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.collection.adder.source;
+
+import java.util.List;
+
+/**
+ * @author Filip Hrisafov
+ */
+public class SourceWithPets {
+
+    private List<String> pets;
+
+    public List<String> getPets() {
+        return pets;
+    }
+
+    public void setPets(List<String> pets) {
+        this.pets = pets;
+    }
+}

processor/src/test/resources/fixtures/org/mapstruct/ap/test/collection/adder/SourceTargetMapperWithDifferentPropertiesImpl.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.collection.adder;
+
+import javax.annotation.Generated;
+import org.mapstruct.ap.test.collection.adder._target.TargetWithAnimals;
+import org.mapstruct.ap.test.collection.adder.source.SourceWithPets;
+
+@Generated(
+    value = "org.mapstruct.ap.MappingProcessor",
+    date = "2018-10-13T10:43:55+0200",
+    comments = "version: , compiler: javac, environment: Java 1.8.0_161 (Oracle Corporation)"
+)
+public class SourceTargetMapperWithDifferentPropertiesImpl implements SourceTargetMapperWithDifferentProperties {
+
+    @Override
+    public TargetWithAnimals map(SourceWithPets source) {
+        if ( source == null ) {
+            return null;
+        }
+
+        TargetWithAnimals targetWithAnimals = new TargetWithAnimals();
+
+        if ( source.getPets() != null ) {
+            for ( String pet : source.getPets() ) {
+                targetWithAnimals.addAnimal( pet );
+            }
+        }
+
+        return targetWithAnimals;
+    }
+}