#124 Making sure variable names always start with a lower-case letter

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

@@ -18,7 +18,6 @@
  */
 package org.mapstruct.ap.model;
 
-import java.beans.Introspector;
 import java.util.List;
 import java.util.Set;
 
@@ -52,7 +51,7 @@ public class DefaultMapperReference extends MapperReference {
         }
 
         String variableName = Strings.getSaveVariableName(
-            Introspector.decapitalize( type.getName() ),
+            type.getName(),
             otherMapperReferences
         );
 

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

@@ -18,7 +18,6 @@
  */
 package org.mapstruct.ap.model;
 
-import java.beans.Introspector;
 import java.util.Set;
 
 import org.mapstruct.ap.model.common.Parameter;
@@ -77,12 +76,8 @@ public class IterableMappingMethod extends MappingMethod {
 
     public String getLoopVariableName() {
         return Strings.getSaveVariableName(
-            Introspector.decapitalize(
+            getSourceParameter().getType().getTypeParameters().get( 0 ).getName(),
-                getSourceParameter().getType()
+            getParameterNames()
-                    .getTypeParameters()
-                    .get( 0 )
-                    .getName()
-            ), getParameterNames()
         );
     }
 

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

@@ -18,7 +18,6 @@
  */
 package org.mapstruct.ap.model;
 
-import java.beans.Introspector;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
@@ -75,7 +74,7 @@ public abstract class MappingMethod extends ModelElement {
 
     public String getResultName() {
         return targetParameter != null ? targetParameter.getName() :
-            Strings.getSaveVariableName( Introspector.decapitalize( getResultType().getName() ), getParameterNames() );
+            Strings.getSaveVariableName( getResultType().getName(), getParameterNames() );
     }
 
     public Type getReturnType() {

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

@@ -18,7 +18,6 @@
  */
 package org.mapstruct.ap.processor;
 
-import java.beans.Introspector;
 import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -27,7 +26,6 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-
 import javax.annotation.processing.Messager;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.ExecutableElement;
@@ -601,7 +599,7 @@ public class MapperCreationProcessor implements ModelElementProcessor<List<Metho
             targetElementType,
             method.getIterableMapping() != null ? method.getIterableMapping().getDateFormat() : null,
             Strings.getSaveVariableName(
-                Introspector.decapitalize( sourceElementType.getName() ),
+                sourceElementType.getName(),
                 method.getParameterNames()
             )
         );

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

@@ -88,8 +88,12 @@ public class Strings {
     private Strings() {
     }
 
-    public static String capitalize(String name) {
+    public static String capitalize(String string) {
-        return name == null ? null : name.substring( 0, 1 ).toUpperCase() + name.substring( 1 );
+        return string == null ? null : string.substring( 0, 1 ).toUpperCase() + string.substring( 1 );
+    }
+
+    public static String decapitalize(String string) {
+        return string == null ? null : string.substring( 0, 1 ).toLowerCase() + string.substring( 1 );
     }
 
     public static String join(Iterable<?> iterable, String separator) {
@@ -118,7 +122,19 @@ public class Strings {
         return getSaveVariableName( name, Arrays.asList( existingVariableNames ) );
     }
 
+    /**
+     * Returns a variable name which doesn't conflict with the given variable names existing in the same scope and the
+     * Java keywords.
+     *
+     * @param name the name to get a safe version for
+     * @param existingVariableNames the names of other variables existing in the same scope
+     *
+     * @return a variable name based on the given original name, not conflicting with any of the given other names or
+     *         any Java keyword; starting with a lower-case letter
+     */
     public static String getSaveVariableName(String name, Collection<String> existingVariableNames) {
+        name = decapitalize( name );
+
         Set<String> conflictingNames = new HashSet<String>( KEYWORDS );
         conflictingNames.addAll( existingVariableNames );