activate extendable builders explicitly (ensure backwards compatibility)

3 files changed, 45 insertions, 11 deletions

diff --git a/src/core/lombok/Builder.java b/src/core/lombok/Builder.java
index 855e96e8..9cf82191 100644
--- a/src/core/lombok/Builder.java
+++ b/src/core/lombok/Builder.java
@@ -123,15 +123,30 @@ public @interface Builder {
 	String builderClassName() default "";
 	
 	/**
-	 * If true, the generated builder class will extend the builder of the
+	 * If true, the generated builder class will extend the {@code @Builder} of the
 	 * superclass. In this way, the builder will also contain methods for fields
-	 * from the superclass. Note that both this builder and the superclass'
-	 * builder must be a type {@code @Builder}; this feature does neither work
-	 * for constructor nor method {@code @Builder}s.
+	 * from the superclass.<br>
+	 * Note that both this builder and the superclass' builder must be a type
+	 * {@code @Builder}; this feature does neither work for constructor nor
+	 * method {@code @Builder}s. The parent {@code @Builder} must be
+	 * {@link #extendable()}. <br>
+	 * Implies {@link #extendable()}.
 	 */
 	boolean inherit() default false;
 
 	/**
+	 * If true, the generated builder pattern will be extendable by
+	 * {@code @Builder}s of subclasses, using the {@link #inherit()} feature.
+	 * This is achieved by generating a special constructor that takes a builder
+	 * instance as parameter (instead of an {@link AllArgsConstructor}). <br>
+	 * Note that this builder must be a type {@code @Builder}; this feature does
+	 * neither work for constructor nor method {@code @Builder}s.<br>
+	 * If {@link #inherit()} {@code == true}, {@link #extendable()} will
+	 * automatically be {@code true}.
+	 */
+	boolean extendable() default false;
+
+	/**
 	 * Name of the builder class in the superclass. Only relevant if
 	 * {@code inherit = true} (see {@link #inherit()}).
 	 * 
diff --git a/src/core/lombok/eclipse/handlers/HandleBuilder.java b/src/core/lombok/eclipse/handlers/HandleBuilder.java
index 4f152fe3..4bfc89f4 100644
--- a/src/core/lombok/eclipse/handlers/HandleBuilder.java
+++ b/src/core/lombok/eclipse/handlers/HandleBuilder.java
@@ -141,6 +141,7 @@ public class HandleBuilder extends EclipseAnnotationHandler<Builder> {
 		String builderClassName = builderInstance.builderClassName();
 		
 		boolean inherit = builderInstance.inherit();
+		boolean extendable = inherit || builderInstance.extendable(); // inherit implies extendable
 		String superclassBuilderClassName = builderInstance.superclassBuilderClassName();
 
 		String toBuilderMethodName = "toBuilder";
@@ -203,9 +204,9 @@ public class HandleBuilder extends EclipseAnnotationHandler<Builder> {
 				superclassBuilderClassName = new String(td.superclass.getLastToken()) + "Builder";
 			}
 			
-			boolean callSuperConstructor = inherit && td.superclass != null;
+			boolean callBuilderBasedSuperConstructor = inherit && td.superclass != null;
 			new HandleConstructor().generateConstructor(tdParent, AccessLevel.PROTECTED, allFields, false, null, SkipIfConstructorExists.I_AM_BUILDER, true,
-				Collections.<Annotation>emptyList(), annotationNode, builderClassName, callSuperConstructor);
+				Collections.<Annotation>emptyList(), annotationNode, extendable ? builderClassName : null, callBuilderBasedSuperConstructor);
 			
 			returnType = namePlusTypeParamsToTypeReference(td.name, td.typeParameters, p);
 			typeParams = td.typeParameters;
@@ -216,6 +217,10 @@ public class HandleBuilder extends EclipseAnnotationHandler<Builder> {
 				annotationNode.addError("@Builder(inherit=true) is only supported for type builders.");
 				return;
 			}
+			if (extendable) {
+				annotationNode.addError("@Builder(extendable=true) is only supported for type builders.");
+				return;
+			}
 			ConstructorDeclaration cd = (ConstructorDeclaration) parent.get();
 			if (cd.typeParameters != null && cd.typeParameters.length > 0) {
 				annotationNode.addError("@Builder is not supported on constructors with constructor type parameters.");
@@ -234,6 +239,10 @@ public class HandleBuilder extends EclipseAnnotationHandler<Builder> {
 				annotationNode.addError("@Builder(inherit=true) is only supported for type builders.");
 				return;
 			}
+			if (extendable) {
+				annotationNode.addError("@Builder(extendable=true) is only supported for type builders.");
+				return;
+			}
 			MethodDeclaration md = (MethodDeclaration) parent.get();
 			tdParent = parent.up();
 			isStatic = md.isStatic();
@@ -427,7 +436,7 @@ public class HandleBuilder extends EclipseAnnotationHandler<Builder> {
 		}
 		
 		if (methodExists(buildMethodName, builderType, -1) == MemberExistsResult.NOT_EXISTS) {
-			boolean useBuilderBasedConstructor = parent.get() instanceof TypeDeclaration;
+			boolean useBuilderBasedConstructor = parent.get() instanceof TypeDeclaration && extendable;
 			MethodDeclaration md = generateBuildMethod(isStatic, buildMethodName, nameOfStaticBuilderMethod, returnType, builderFields, builderType, thrownExceptions, addCleaning, ast, useBuilderBasedConstructor);
 			if (md != null) injectMethod(builderType, md);
 		}
diff --git a/src/core/lombok/javac/handlers/HandleBuilder.java b/src/core/lombok/javac/handlers/HandleBuilder.java
index 32bf7949..7701d85c 100644
--- a/src/core/lombok/javac/handlers/HandleBuilder.java
+++ b/src/core/lombok/javac/handlers/HandleBuilder.java
@@ -110,6 +110,7 @@ public class HandleBuilder extends JavacAnnotationHandler<Builder> {
 		String toBuilderMethodName = "toBuilder";
 		
 		boolean inherit = builderInstance.inherit();
+		boolean extendable = inherit || builderInstance.extendable(); // inherit implies extendable
 		String superclassBuilderClassName = builderInstance.superclassBuilderClassName();
 
 		boolean toBuilder = builderInstance.toBuilder();
@@ -176,8 +177,8 @@ public class HandleBuilder extends JavacAnnotationHandler<Builder> {
 				superclassBuilderClassName = extendsClause + "Builder";
 			}
 			
-			boolean callSuperConstructor = inherit && extendsClause != null;
-			new HandleConstructor().generateConstructor(tdParent, AccessLevel.PROTECTED, List.<JCAnnotation>nil(), allFields.toList(), false, null, SkipIfConstructorExists.I_AM_BUILDER, null, annotationNode, builderClassName, callSuperConstructor);
+			boolean callBuilderBasedSuperConstructor = inherit && extendsClause != null;
+			new HandleConstructor().generateConstructor(tdParent, AccessLevel.PROTECTED, List.<JCAnnotation>nil(), allFields.toList(), false, null, SkipIfConstructorExists.I_AM_BUILDER, null, annotationNode, extendable ? builderClassName : null, callBuilderBasedSuperConstructor);
 			
 			returnType = namePlusTypeParamsToTypeReference(tdParent.getTreeMaker(), td.name, td.typarams);
 			typeParams = td.typarams;
@@ -187,7 +188,12 @@ public class HandleBuilder extends JavacAnnotationHandler<Builder> {
 			if (inherit) {
 				annotationNode.addError("@Builder(inherit=true) is only supported for type builders.");
 				return;
-			}			JCMethodDecl jmd = (JCMethodDecl) fillParametersFrom.get();
+			}
+			if (extendable) {
+				annotationNode.addError("@Builder(extendable=true) is only supported for type builders.");
+				return;
+			}
+			JCMethodDecl jmd = (JCMethodDecl) fillParametersFrom.get();
 			if (!jmd.typarams.isEmpty()) {
 				annotationNode.addError("@Builder is not supported on constructors with constructor type parameters.");
 				return;
@@ -205,6 +211,10 @@ public class HandleBuilder extends JavacAnnotationHandler<Builder> {
 				annotationNode.addError("@Builder(inherit=true) is only supported for type builders.");
 				return;
 			}
+			if (extendable) {
+				annotationNode.addError("@Builder(extendable=true) is only supported for type builders.");
+				return;
+			}
 			tdParent = parent.up();
 			JCClassDecl td = (JCClassDecl) tdParent.get();
 			JCMethodDecl jmd = (JCMethodDecl) fillParametersFrom.get();
@@ -387,7 +397,7 @@ public class HandleBuilder extends JavacAnnotationHandler<Builder> {
 		}
 		
 		if (methodExists(buildMethodName, builderType, -1) == MemberExistsResult.NOT_EXISTS) {
-			boolean useBuilderBasedConstructor = parent.get() instanceof JCClassDecl;
+			boolean useBuilderBasedConstructor = parent.get() instanceof JCClassDecl && extendable;
 			JCMethodDecl md = generateBuildMethod(isStatic, buildMethodName, nameOfBuilderMethod, returnType, builderFields, builderType, thrownExceptions, ast, addCleaning, useBuilderBasedConstructor);
 			if (md != null) injectMethod(builderType, md);
 		}