8172910: Use default methods as appropriate for language model visitors
Reviewed-by: jjg
--- a/langtools/src/java.compiler/share/classes/javax/lang/model/element/AnnotationValueVisitor.java Wed Jan 18 21:09:19 2017 +0300
+++ b/langtools/src/java.compiler/share/classes/javax/lang/model/element/AnnotationValueVisitor.java Wed Jan 18 19:39:06 2017 -0800
@@ -68,8 +68,8 @@
* javax.lang.model.*} packages bundled in Java SE 8 were required to
* also be runnable on Java SE 7. Therefore, default methods
* were <em>not</em> used when extending {@code javax.lang.model.*}
- * to cover Java SE 8 language features. However, default methods may
- * be used in subsequent revisions of the {@code javax.lang.model.*}
+ * to cover Java SE 8 language features. However, default methods
+ * are used in subsequent revisions of the {@code javax.lang.model.*}
* packages that are only required to run on Java SE 8 and higher
* platform versions.
*
@@ -90,11 +90,16 @@
R visit(AnnotationValue av, P p);
/**
- * A convenience method equivalent to {@code v.visit(av, null)}.
+ * A convenience method equivalent to {@code visit(av, null)}.
+ *
+ * @implSpec The default implementation is {@code visit(av, null)}.
+ *
* @param av the value to visit
* @return a visitor-specified result
*/
- R visit(AnnotationValue av);
+ default R visit(AnnotationValue av) {
+ return visit(av, null);
+ }
/**
* Visits a {@code boolean} value in an annotation.
--- a/langtools/src/java.compiler/share/classes/javax/lang/model/element/ElementVisitor.java Wed Jan 18 21:09:19 2017 +0300
+++ b/langtools/src/java.compiler/share/classes/javax/lang/model/element/ElementVisitor.java Wed Jan 18 19:39:06 2017 -0800
@@ -59,8 +59,8 @@
* javax.lang.model.*} packages bundled in Java SE 8 were required to
* also be runnable on Java SE 7. Therefore, default methods
* were <em>not</em> used when extending {@code javax.lang.model.*}
- * to cover Java SE 8 language features. However, default methods may
- * be used in subsequent revisions of the {@code javax.lang.model.*}
+ * to cover Java SE 8 language features. However, default methods
+ * are used in subsequent revisions of the {@code javax.lang.model.*}
* packages that are only required to run on Java SE 8 and higher
* platform versions.
*
@@ -85,11 +85,16 @@
R visit(Element e, P p);
/**
- * A convenience method equivalent to {@code v.visit(e, null)}.
+ * A convenience method equivalent to {@code visit(e, null)}.
+ *
+ * @implSpec The default implementation is {@code visit(e, null)}.
+ *
* @param e the element to visit
* @return a visitor-specified result
*/
- R visit(Element e);
+ default R visit(Element e) {
+ return visit(e, null);
+ }
/**
* Visits a package element.
@@ -146,10 +151,16 @@
/**
* Visits a module element.
+ *
+ * @implSpec Visits a {@code ModuleElement} by calling {@code
+ * visitUnknown(e, p)}.
+ *
* @param e the element to visit
* @param p a visitor-specified parameter
* @return a visitor-specified result
* @since 9
*/
- R visitModule(ModuleElement e, P p);
+ default R visitModule(ModuleElement e, P p) {
+ return visitUnknown(e, p);
+ }
}
--- a/langtools/src/java.compiler/share/classes/javax/lang/model/type/TypeVisitor.java Wed Jan 18 21:09:19 2017 +0300
+++ b/langtools/src/java.compiler/share/classes/javax/lang/model/type/TypeVisitor.java Wed Jan 18 19:39:06 2017 -0800
@@ -59,8 +59,8 @@
* javax.lang.model.*} packages bundled in Java SE 8 were required to
* also be runnable on Java SE 7. Therefore, default methods
* were <em>not</em> used when extending {@code javax.lang.model.*}
- * to cover Java SE 8 language features. However, default methods may
- * be used in subsequent revisions of the {@code javax.lang.model.*}
+ * to cover Java SE 8 language features. However, default methods
+ * are used in subsequent revisions of the {@code javax.lang.model.*}
* packages that are only required to run on Java SE 8 and higher
* platform versions.
*
@@ -85,11 +85,16 @@
R visit(TypeMirror t, P p);
/**
- * A convenience method equivalent to {@code v.visit(t, null)}.
+ * A convenience method equivalent to {@code visit(t, null)}.
+ *
+ * @implSpec The default implementation is {@code visit(t, null)}.
+ *
* @param t the element to visit
* @return a visitor-specified result
*/
- R visit(TypeMirror t);
+ default R visit(TypeMirror t) {
+ return visit(t, null);
+ }
/**
* Visits a primitive type.
--- a/langtools/src/java.compiler/share/classes/javax/lang/model/util/AbstractElementVisitor6.java Wed Jan 18 21:09:19 2017 +0300
+++ b/langtools/src/java.compiler/share/classes/javax/lang/model/util/AbstractElementVisitor6.java Wed Jan 18 19:39:06 2017 -0800
@@ -139,6 +139,7 @@
*/
@Override
public R visitModule(ModuleElement e, P p) {
- return visitUnknown(e, p);
+ // Use implementation from interface default method
+ return ElementVisitor.super.visitModule(e, p);
}
}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/test/tools/javac/processing/model/TestVisitorDefaults.java Wed Jan 18 19:39:06 2017 -0800
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8172910
+ * @summary Test behavior of default methods on visitors.
+ * @modules java.compiler
+ */
+
+import java.util.List;
+import javax.lang.model.SourceVersion;
+import javax.lang.model.element.*;
+import javax.lang.model.type.*;
+import javax.lang.model.util.*;
+
+/**
+ * Verify expected behavior of default methods on visitors.
+ */
+public class TestVisitorDefaults {
+ public static void main(String... args) {
+ DirectElementVisitorChild dvc = new DirectElementVisitorChild();
+ if (!"visitUnknown".equals(dvc.visitModule(null, null))) {
+ throw new RuntimeException("Problem with DirectElementVisitorChild");
+ }
+ if (!"visit".equals(dvc.visit(null))) {
+ throw new RuntimeException("Problem with DirectElementVisitorChild");
+ }
+
+ IndirectElementVisitorChild ivc = new IndirectElementVisitorChild();
+ if (!"visitUnknown".equals(ivc.visitModule(null, null))) {
+ throw new RuntimeException("Problem with IndirectElementVisitorChild");
+ }
+
+ DirectTypeVisitorChild dtvc = new DirectTypeVisitorChild();
+ if (!"visit".equals(dtvc.visit(null))) {
+ throw new RuntimeException("Problem with DirectTypeVisitorChild");
+ }
+
+ DirectAnnotationVisitorChild davc = new DirectAnnotationVisitorChild();
+ if (!"visit".equals(davc.visit(null))) {
+ throw new RuntimeException("Problem with DirectAnnotationVisitorChild");
+ }
+ }
+
+ private static class DirectElementVisitorChild
+ implements ElementVisitor<String, Object> {
+
+ public DirectElementVisitorChild() {
+ super();
+ }
+
+ @Override
+ public String visitModule(ModuleElement e, Object o) {
+ return ElementVisitor.super.visitModule(e, null);
+ }
+
+ @Override
+ public String visitUnknown(Element e, Object o) {
+ return "visitUnknown";
+ }
+
+ @Override
+ public String visit(Element e) {
+ return ElementVisitor.super.visit(e);
+ }
+
+ @Override
+ public String visit(Element e, Object o) {
+ return "visit";
+ }
+
+ @Override
+ public String visitExecutable(ExecutableElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitPackage(PackageElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitType(TypeElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitTypeParameter(TypeParameterElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitVariable(VariableElement e, Object o) { return throwUOE(); }
+ }
+
+ private static class IndirectElementVisitorChild
+ extends AbstractElementVisitor6<String, Object> {
+
+ public IndirectElementVisitorChild() {
+ super();
+ }
+
+ @Override
+ public String visitModule(ModuleElement e, Object o) {
+ return super.visitModule(e, o);
+ }
+
+
+ @Override
+ public String visitUnknown(Element e, Object o) {
+ return "visitUnknown";
+ }
+
+ @Override
+ public String visitExecutable(ExecutableElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitPackage(PackageElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitType(TypeElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitTypeParameter(TypeParameterElement e, Object o) { return throwUOE(); }
+ @Override
+ public String visitVariable(VariableElement e, Object o) { return throwUOE(); }
+ }
+
+
+ private static class DirectTypeVisitorChild
+ implements TypeVisitor<String, Object> {
+
+ public DirectTypeVisitorChild() {
+ super();
+ }
+
+ @Override
+ public String visit(TypeMirror t) {
+ return TypeVisitor.super.visit(t);
+ }
+
+ @Override
+ public String visit(TypeMirror t, Object o) {
+ return "visit";
+ }
+
+ @Override
+ public String visitUnknown(TypeMirror t, Object o) { return throwUOE(); }
+ @Override
+ public String visitArray(ArrayType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitDeclared(DeclaredType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitError(ErrorType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitExecutable(ExecutableType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitIntersection(IntersectionType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitNoType(NoType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitNull(NullType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitPrimitive(PrimitiveType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitTypeVariable(TypeVariable t, Object o) { return throwUOE(); }
+ @Override
+ public String visitUnion(UnionType t, Object o) { return throwUOE(); }
+ @Override
+ public String visitWildcard(WildcardType t, Object o) { return throwUOE(); }
+ }
+
+ private static class DirectAnnotationVisitorChild
+ implements AnnotationValueVisitor<String, Object> {
+
+ @Override
+ public String visit(AnnotationValue av) {
+ return AnnotationValueVisitor.super.visit(av);
+ }
+
+ @Override
+ public String visit(AnnotationValue av, Object o) {
+ return "visit";
+ }
+
+ @Override
+ public String visitAnnotation(AnnotationMirror a, Object o) { return throwUOE(); }
+ @Override
+ public String visitArray(List<? extends AnnotationValue> vals,
+ Object o) { return throwUOE(); }
+ @Override
+ public String visitBoolean(boolean b, Object o) { return throwUOE(); }
+ @Override
+ public String visitByte(byte b, Object o) { return throwUOE(); }
+ @Override
+ public String visitChar(char c, Object o) { return throwUOE(); }
+ @Override
+ public String visitDouble(double d, Object o) { return throwUOE(); }
+ @Override
+ public String visitEnumConstant(VariableElement c, Object o) { return throwUOE(); }
+ @Override
+ public String visitFloat(float f, Object o) { return throwUOE(); }
+ @Override
+ public String visitInt(int i, Object o) { return throwUOE(); }
+ @Override
+ public String visitLong(long i, Object o) { return throwUOE(); }
+ @Override
+ public String visitShort(short s, Object o) { return throwUOE(); }
+ @Override
+ public String visitString(String s, Object o) { return throwUOE(); }
+ @Override
+ public String visitType(TypeMirror t, Object o) { return throwUOE(); }
+ @Override
+ public String visitUnknown(AnnotationValue av, Object o) { return throwUOE(); }
+ }
+
+ private static String throwUOE() {
+ throw new UnsupportedOperationException();
+ }
+}