/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.i18n.rebind;
import com.google.gwt.core.ext.typeinfo.JClassType;
import java.lang.annotation.Annotation;
/**
* Utility class for i18n-related annotation manipulation routines.
*/
public class AnnotationUtil {
/**
* Find an instance of the specified annotation, walking up the inheritance
* tree if necessary.
*
* <p>Note that i18n annotations may appear on classes as well as interfaces
* (a concrete implementation can be supplied rather than just an interface
* and this is the normal way of using generic Localizable interfaces), so
* we have to search the super chain as well as other interfaces.
*
* <p>The super chain is walked first, so if an ancestor superclass has the
* requested annotation, it will be preferred over a directly implemented
* interface.
*
* @param <T> Annotation type to search for
* @param clazz root class to search, may be null
* @param annotationClass class object of Annotation subclass to search for
* @return the requested annotation or null if none
*/
static <T extends Annotation> T getClassAnnotation(JClassType clazz,
Class<T> annotationClass) {
if (clazz == null) {
return null;
}
T annot = clazz.getAnnotation(annotationClass);
if (annot == null) {
annot = getClassAnnotation(clazz.getSuperclass(), annotationClass);
if (annot != null) {
return annot;
}
for (JClassType intf : clazz.getImplementedInterfaces()) {
annot = getClassAnnotation(intf, annotationClass);
if (annot != null) {
return annot;
}
}
}
return annot;
}
}