1/*
2 * Copyright (C) 2012 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.util.concurrent;
18
19import com.google.common.base.Function;
20import com.google.common.base.Throwables;
21import com.google.common.collect.ForwardingObject;
22import com.google.common.collect.Iterables;
23import com.google.common.testing.ForwardingWrapperTester;
24
25import org.easymock.EasyMock;
26
27import java.lang.reflect.Method;
28import java.util.Arrays;
29
30/**
31 * Tester for typical subclass of {@link ForwardingObject} by using EasyMock partial mocks.
32 *
33 * @author Ben Yu
34 */
35final class ForwardingObjectTester {
36
37  private static final Method DELEGATE_METHOD;
38  static {
39    try {
40      DELEGATE_METHOD = ForwardingObject.class.getDeclaredMethod("delegate");
41      DELEGATE_METHOD.setAccessible(true);
42    } catch (SecurityException e) {
43      throw new RuntimeException(e);
44    } catch (NoSuchMethodException e) {
45      throw new AssertionError(e);
46    }
47  }
48
49  /**
50   * Ensures that all interface methods of {@code forwarderClass} are forwarded to the
51   * {@link ForwardingObject#delegate}. {@code forwarderClass} is assumed to only implement one
52   * interface.
53   */
54  static <T extends ForwardingObject> void testForwardingObject(final Class<T> forwarderClass) {
55    @SuppressWarnings("unchecked") // super interface type of T
56    Class<? super T> interfaceType = (Class<? super T>)
57        Iterables.getOnlyElement(Arrays.asList(forwarderClass.getInterfaces()));
58    new ForwardingWrapperTester().testForwarding(interfaceType, new Function<Object, T>() {
59      @Override public T apply(Object delegate) {
60        T mock = EasyMock.createMockBuilder(forwarderClass)
61            .addMockedMethod(DELEGATE_METHOD)
62            .createMock();
63        try {
64          DELEGATE_METHOD.invoke(mock);
65        } catch (Exception e) {
66          throw Throwables.propagate(e);
67        }
68        EasyMock.expectLastCall().andStubReturn(delegate);
69        EasyMock.replay(mock);
70        return mock;
71      }
72    });
73  }
74}
75