JDK 8 code review request for 8014836: Have GenericDeclaration extend AnnotatedElement (original) (raw)

Remi Forax forax at univ-mlv.fr
Wed May 22 15:36:02 UTC 2013

On 05/21/2013 03:16 AM, Joseph Darcy wrote:

Hi Remi,

On 5/20/2013 2:28 PM, Remi Forax wrote: On 05/20/2013 11:10 PM, Joe Darcy wrote:

Hello,

Please review the patch below which implements 8014836: Have GenericDeclaration extend AnnotatedElement All the existing implementations of GenericDeclaration in the JDK already implement AnnotatedElement. Some code in java.lang.Class needed to be adjusted slightly since AnnotatedElement declares a default method and calling an interface's default method in an implementing class has to go through the direct interface type. GenericDeclaration is a public interface, so you will break the code of everyone that implements it. By example, Guava's Invokable also implements GenericDeclaration http://docs.guava-libraries.googlecode.com/git/javadoc/com/google/common/reflect/Invokable.html That is technically true; in effect adding several methods to GenericDeclaration would break implementations outside of the JDK that do not already implement annotated element. However, this is (only) a source incompatible change and not a binary incompatible change so is possible in-bounds for a platform release like JDK 8: http://cr.openjdk.java.net/~darcy/OpenJdkDevGuide/OpenJdkDevelopersGuide.v0.777.html#generalevolutionpolicy The Invokable type you reference is the moral equivalent of the "Executable" superclass of Constructor and Method added earlier in JDK 8. The Invokable type itself is marked as "@Beta" to warn users that it could change or even to away. Therefore, I'm not very concerned about "breaking" a type like this, which could easily be retrofitted to also implement AnnotatedElement as it already a wrapper around a Method or a Constructor.

For me, it's not just a source incompatible change, let suppose that I use Guava reflection API in my program and the jdk8, I will be able to get a GenericDeclaration that will fail at runtime if I try to call a method of AnnotatedElement on it. So this change make the existing Guava library not forward compatible.

With the introduction of default methods, we now have a way to make change in interfaces backward compatible, I don't say that we should use default methods here, I don't know. But I think it worth to think about that.

I've just seen that AnnotatedElement also includes new new abstract methods.

(Also interesting to see a "Parameter" class in Guava given that we have added a Parameter class to java.lang.reflect.)

yes, but there is no getName() :)

Thanks, -Joe

cheers, Rémi

Thanks, -Joe Rémi --- a/src/share/classes/java/lang/Class.java Mon May 20 11:56:46 2013 -0700 +++ b/src/share/classes/java/lang/Class.java Mon May 20 14:07:15 2013 -0700 @@ -28,6 +28,7 @@ import java.lang.reflect.AnnotatedElement; import java.lang.reflect.Array; import java.lang.reflect.GenericArrayType; +import java.lang.reflect.GenericDeclaration; import java.lang.reflect.Member; import java.lang.reflect.Field; import java.lang.reflect.Executable; @@ -115,9 +116,9 @@ * @since JDK1.0 */ public final class Class implements java.io.Serializable, - java.lang.reflect.GenericDeclaration, - java.lang.reflect.Type, - java.lang.reflect.AnnotatedElement { + GenericDeclaration, + Type, + AnnotatedElement { private static final int ANNOTATION= 0x00002000; private static final int ENUM = 0x00004000; private static final int SYNTHETIC = 0x00001000; @@ -3182,7 +3183,7 @@ */ @Override public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) { - return AnnotatedElement.super.isAnnotationPresent(annotationClass); + return GenericDeclaration.super.isAnnotationPresent(annotationClass); } /** diff -r 6a9148865139 src/share/classes/java/lang/reflect/GenericDeclaration.java --- a/src/share/classes/java/lang/reflect/GenericDeclaration.java Mon May 20 11:56:46 2013 -0700 +++ b/src/share/classes/java/lang/reflect/GenericDeclaration.java Mon May 20 14:07:15 2013 -0700 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2003, 2013, 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 @@ -30,7 +30,7 @@ * * @since 1.5 */ -public interface GenericDeclaration { +public interface GenericDeclaration extends AnnotatedElement { /** * Returns an array of {@code TypeVariable} objects that * represent the type variables declared by the generic

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