SuperBuilder: generate toBuilder method (ecj)

src/core/lombok/eclipse/handlers/HandleSuperBuilder.java

@@ -104,7 +104,8 @@ public class HandleSuperBuilder extends EclipseAnnotationHandler<SuperBuilder> {
 	private static final char[] DEFAULT_PREFIX = "$default$".toCharArray();
 	private static final char[] SET_PREFIX = "$set".toCharArray();
 	private static final char[] SELF_METHOD_NAME = "self".toCharArray();
-	private static final char[] TO_BUILDER_METHOD_NAME = "toBuilder".toCharArray();
+	private static final String TO_BUILDER_METHOD_NAME_STRING = "toBuilder";
+	private static final char[] TO_BUILDER_METHOD_NAME = TO_BUILDER_METHOD_NAME_STRING.toCharArray();
 	private static final char[] FILL_VALUES_METHOD_NAME = "$fillValuesFrom".toCharArray();
 	private static final char[] EMPTY_LIST = "emptyList".toCharArray();
 	
@@ -345,6 +346,15 @@ public class HandleSuperBuilder extends EclipseAnnotationHandler<SuperBuilder> {
 			MethodDeclaration md = generateBuilderMethod(builderMethodName, builderClassName, builderImplClassName, tdParent, typeParams, ast);
 			if (md != null) injectMethod(tdParent, md);
 		}
+
+		if (toBuilder) switch (methodExists(TO_BUILDER_METHOD_NAME_STRING, tdParent, 0)) {
+		case EXISTS_BY_USER:
+			annotationNode.addWarning("Not generating toBuilder() as it already exists.");
+			break;
+		case NOT_EXISTS:
+			MethodDeclaration md = generateToBuilderMethod(builderClassName, builderImplClassName, tdParent, typeParams, ast);
+			if (md != null) injectMethod(tdParent, md);
+		}
 	}
 	
 	private EclipseNode generateBuilderAbstractClass(EclipseNode tdParent, String builderClass,
@@ -534,6 +544,41 @@ public class HandleSuperBuilder extends EclipseAnnotationHandler<SuperBuilder> {
 		return out;
 	}
 	
+	/**
+	 * Generates a <code>toBuilder()</code> method in the annotated class that looks like this:
+	 * <pre>
+	 * public ParentBuilder&lt;?, ?&gt; toBuilder() {
+	 *     return new <i>Foobar</i>BuilderImpl().$fillValuesFrom(this);
+	 * }
+	 * </pre>
+	 */
+	private MethodDeclaration generateToBuilderMethod(String builderClassName, String builderImplClassName, EclipseNode type, TypeParameter[] typeParams, ASTNode source) {
+		int pS = source.sourceStart, pE = source.sourceEnd;
+		long p = (long) pS << 32 | pE;
+		
+		MethodDeclaration out = new MethodDeclaration(((CompilationUnitDeclaration) type.top().get()).compilationResult);
+		out.selector = TO_BUILDER_METHOD_NAME;
+		out.modifiers = ClassFileConstants.AccPublic;
+		out.bits |= ECLIPSE_DO_NOT_TOUCH_FLAG;
+		
+		// Add type params if there are any.
+		if (typeParams != null && typeParams.length > 0) out.typeParameters = copyTypeParams(typeParams, source);
+		
+		TypeReference[] wildcards = new TypeReference[] {new Wildcard(Wildcard.UNBOUND), new Wildcard(Wildcard.UNBOUND) };
+		out.returnType = new ParameterizedSingleTypeReference(builderClassName.toCharArray(), mergeToTypeReferences(typeParams, wildcards), 0, p);
+		
+		AllocationExpression newClass = new AllocationExpression();
+		newClass.type = namePlusTypeParamsToTypeReference(builderImplClassName.toCharArray(), typeParams, p);
+		MessageSend invokeFillMethod = new MessageSend();
+		invokeFillMethod.receiver = newClass;
+		invokeFillMethod.selector = FILL_VALUES_METHOD_NAME;
+		invokeFillMethod.arguments = new Expression[] {new ThisReference(0, 0)};
+		out.statements = new Statement[] {new ReturnStatement(invokeFillMethod, pS, pE)};
+		
+		out.traverse(new SetGeneratedByVisitor(source), ((TypeDeclaration) type.get()).scope);
+		return out;
+	}
+
 	/**
 	 * Generates a <code>$fillValuesFrom()</code> method in the abstract builder class that looks
 	 * like this:

src/core/lombok/javac/handlers/HandleSuperBuilder.java

@@ -523,7 +523,6 @@ public class HandleSuperBuilder extends JavacAnnotationHandler<SuperBuilder> {
 		JCExpression newClass = maker.NewClass(null, List.<JCExpression>nil(), namePlusTypeParamsToTypeReference(maker, type.toName(builderImplClassName), typeParams), List.<JCExpression>nil(), null);
 		List<JCExpression> methodArgs = List.<JCExpression>of(maker.Ident(type.toName("this")));
 		JCMethodInvocation invokeFillMethod = maker.Apply(List.<JCExpression>nil(), maker.Select(newClass, type.toName(FILL_VALUES_METHOD_NAME)), methodArgs);
-//		JCMethodInvocation invokeFillMethod = maker.Apply(List.<JCExpression>nil(), maker.Select(newClass, type.toName(FILL_VALUES_METHOD_NAME)), List.<JCExpression>nil());
 		JCStatement statement = maker.Return(invokeFillMethod);
 		
 		JCBlock body = maker.Block(0, List.<JCStatement>of(statement));

test/transform/resource/after-ecj/SuperBuilderBasicToBuilder.java

@@ -82,7 +82,7 @@ public class SuperBuilderBasicToBuilder {
       public ChildBuilder() {
         super();
       }
-      protected @java.lang.Override @java.lang.SuppressWarnings("all") B $fillValuesFrom(C instance) {
+      protected @java.lang.Override @java.lang.SuppressWarnings("all") B $fillValuesFrom(final C instance) {
         super.$fillValuesFrom(instance);
         field3(instance.field3);
         return self();
@@ -120,10 +120,10 @@ public class SuperBuilderBasicToBuilder {
       return new ChildBuilderImpl().$fillValuesFrom(this);
     }
   }
-  public SuperBuilderBasic() {
+  public SuperBuilderBasicToBuilder() {
     super();
   }
   public static void test() {
-    Child x = Child.builder().field3(0.0).field1(5).item("").build();
+    Child x = Child.builder().field3(0.0).field1(5).item("").build().toBuilder().build();
   }
 }