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https://issues.apache.org/jira/browse/WINK-363?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Georg Sander updated WINK-363:
------------------------------
Attachment: GenericsUtils.java
Attached the version I used for debugging, just for the purpose of my granting
you license for inclusion.
If I might have left debug code inside that file, please ignore. I have no
clean version at hand right now. Look only at the method isAssignableFrom,
that's where the change must go.
> 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
> Attachments: GenericsUtils.java
>
>
> 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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