001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     bstefanescu
018 */
019package org.nuxeo.runtime.test.runner;
020
021import java.lang.annotation.Annotation;
022import java.lang.reflect.InvocationHandler;
023import java.lang.reflect.Method;
024import java.lang.reflect.Proxy;
025import java.util.Arrays;
026import java.util.Collections;
027
028/**
029 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
030 */
031public class Defaults<A extends Annotation> implements InvocationHandler {
032
033    @SuppressWarnings("unchecked")
034    public static <A extends Annotation> A of(Class<A> annotation) {
035        return (A) Proxy.newProxyInstance(annotation.getClassLoader(), new Class[] { annotation }, new Defaults<A>());
036    }
037
038    @SuppressWarnings("unchecked")
039    public static <A extends Annotation> A of(Class<A> type, Iterable<A> annotations) {
040        return (A) Proxy.newProxyInstance(type.getClassLoader(), new Class[] { type }, new Defaults<>(annotations));
041    }
042
043    @SafeVarargs
044    public static <A extends Annotation> A of(Class<A> type, A... annotations) {
045        return of(type, Arrays.asList(annotations));
046    }
047
048    protected Defaults() {
049        this.annotations = Collections.emptyList();
050    }
051
052    protected Defaults(Iterable<A> annotations) {
053        this.annotations = annotations;
054    }
055
056    protected final Iterable<A> annotations;
057
058    @Override
059    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
060        final Object defaultValue = method.getDefaultValue();
061        for (Annotation each : annotations) {
062            if (each == null) {
063                continue;
064            }
065            Object value = method.invoke(each);
066            if (value != null && !value.equals(defaultValue)) {
067                return value;
068            }
069        }
070        return defaultValue;
071    }
072}