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https://issues.apache.org/jira/browse/WINK-363?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13221103#comment-13221103
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Kevan Miller commented on WINK-363:
-----------------------------------
Thanks Georg.
Your code above is assumed to be a contribution to the ASF under the Apache
License v2 (and thus we could incorporate into Wink).
Attaching the source (preferably as a patch file) to the Jira and clicking the
"Grant license to ASF for inclusion in ASF works (as per the Apache License
ยง5)" radio button makes the licensing of your contribution explicit.
The latter method is preferred, but not absolutely necessary. Doesn't look like
Wink has any documentation on this (something for the to do list).
> Failure to find array entity providers (such as ByteArrayProvider) in Java 7
> ----------------------------------------------------------------------------
>
> Key: WINK-363
> URL: https://issues.apache.org/jira/browse/WINK-363
> Project: Wink
> Issue Type: Bug
> Components: Providers
> Affects Versions: 1.1.3
> Environment: Linux, Java 1.7.0-b147
> Reporter: Georg Sander
>
> The ByteArrayProvider is properly registered and is found through
> ProvidersRegistry in Java 6,but not in Java 7. The effect is a consequence of
> Java bug http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5041784 which got
> fixed in Java 7. It can also affect other array entity providers.
> Explanation:
> ProvidersRegistry collects the providers for the target type byte[] by
> checking whether the provider type and the target type are assignable. The
> corresponding utilities are in GenericsUtils. To determine the provider type,
> GenericsUtil.getGenericInterfaceParamType retrieves the type from the generic
> interfaces of ByteArrayProvider. The type parameters in the generic
> interfaces are represented as java.lang.reflect.Type in Java 6 but as
> java.lang.Class in Java 7. As consequence, the method
> GenericsUtils.isAssignableFrom fails to see that the type parameter is an
> array, hence it returns that byte[] is not assignable to the retrieved type
> of ByteArrayProvider.
> Here is a simple Java program that explains the difference between Java 6 and
> Java 7.
> In Java 6, the output is:
> Type Parameter byte[]
> Type Parameter class class
> sun.reflect.generics.reflectiveObjects.GenericArrayTypeImpl
> Is Generic Array true
> In Java 7, the output is:
> Type Parameter class [B
> Type Parameter class class java.lang.Class
> Is Generic Array false
> {code}
> import java.lang.reflect.GenericArrayType;
> import java.lang.reflect.ParameterizedType;
> import java.lang.reflect.Type;
> public class Test
> {
> public static void main(String[] args) {
> Class cls = ByteArrayProvider.class;
> Type[] interfaces = cls.getGenericInterfaces();
> for (Type type : interfaces) {
> if (type instanceof ParameterizedType) {
> ParameterizedType pType = (ParameterizedType)type;
> Type t = pType.getActualTypeArguments()[0];
> System.err.println("Type Parameter " + t);
> System.err.println("Type Parameter class " + t.getClass());
> System.err.println("Is Generic Array " + (t instanceof
> GenericArrayType));
> }
> }
> }
> }
> interface MessageBodyWriter<T> { }
> class ByteArrayProvider implements MessageBodyWriter<byte[]> { }
> {code}
> I suggest the following fix in GenericsUtils (tested locally in Wink 1.1.3):
> {code:title=GenericsUtils.isAssignableFrom|borderStyle=solid}
> public static boolean isAssignableFrom(Type type, Class<?> cls) {
> if (cls.isArray()) {
> if (type instanceof GenericArrayType) {
> GenericArrayType genericArray = (GenericArrayType)type;
> Class<?> componentType = cls.getComponentType();
> return
> isAssignableFrom(genericArray.getGenericComponentType(), componentType);
> }
> else if ((type instanceof Class<?>) &&
> ((Class<?>)type).isArray()) {
> Class<?> componentType1 = ((Class<?>)type).getComponentType();
> Class<?> componentType2 = cls.getComponentType();
> return isAssignableFrom(componentType1, componentType2);
> }
> } else {
> if (type instanceof GenericArrayType == false) {
> Class<?> classType = getClassType(type, null);
> if (classType == Object.class ||
> classType.isAssignableFrom(cls)) {
> return true;
> }
> }
> }
> return false;
> }
> {code}
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