1/*
2 * Copyright (C) 2007 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.testing;
18
19import com.google.common.annotations.Beta;
20import com.google.common.annotations.GwtCompatible;
21
22import junit.framework.Assert;
23import junit.framework.AssertionFailedError;
24
25/**
26 * Tests serialization and deserialization of an object, optionally asserting
27 * that the resulting object is equal to the original.
28 *
29 * <p><b>GWT warning:</b> Under GWT, both methods simply returns their input,
30 * as proper GWT serialization tests require more setup.  This no-op behavior
31 * allows test authors to intersperse {@code SerializableTester} calls with
32 * other, GWT-compatible tests.
33 *
34 *
35 * @author Mike Bostock
36 * @since 10.0
37 */
38@Beta
39@GwtCompatible // but no-op!
40public final class SerializableTester {
41  private SerializableTester() {}
42
43  /**
44   * Serializes and deserializes the specified object.
45   *
46   * <p><b>GWT warning:</b> Under GWT, this method simply returns its input, as
47   * proper GWT serialization tests require more setup.  This no-op behavior
48   * allows test authors to intersperse {@code SerializableTester} calls with
49   * other, GWT-compatible tests.
50   *
51   * <p>Note that the specified object may not be known by the compiler to be a
52   * {@link java.io.Serializable} instance, and is thus declared an
53   * {@code Object}. For example, it might be declared as a {@code List}.
54   *
55   * @return the re-serialized object
56   * @throws RuntimeException if the specified object was not successfully
57   *     serialized or deserialized
58   */
59  @SuppressWarnings("unchecked")
60  public static <T> T reserialize(T object) {
61    return Platform.reserialize(object);
62  }
63
64  /**
65   * Serializes and deserializes the specified object and verifies that the
66   * re-serialized object is equal to the provided object, that the hashcodes
67   * are identical, and that the class of the re-serialized object is identical
68   * to that of the original.
69   *
70   * <p><b>GWT warning:</b> Under GWT, this method simply returns its input, as
71   * proper GWT serialization tests require more setup.  This no-op behavior
72   * allows test authors to intersperse {@code SerializableTester} calls with
73   * other, GWT-compatible tests.
74   *
75   * <p>Note that the specified object may not be known by the compiler to be a
76   * {@link java.io.Serializable} instance, and is thus declared an
77   * {@code Object}. For example, it might be declared as a {@code List}.
78   *
79   * <p>Note also that serialization is not in general required to return an
80   * object that is {@linkplain Object#equals equal} to the original, nor is it
81   * required to return even an object of the same class. For example, if
82   * sublists of {@code MyList} instances were serializable, those sublists
83   * might implement a private {@code MySubList} type but serialize as a plain
84   * {@code MyList} to save space. So long as {@code MyList} has all the public
85   * supertypes of {@code MySubList}, this is safe. For these cases, for which
86   * {@code reserializeAndAssert} is too strict, use {@link #reserialize}.
87   *
88   * @return the re-serialized object
89   * @throws RuntimeException if the specified object was not successfully
90   *     serialized or deserialized
91   * @throws AssertionFailedError if the re-serialized object is not equal to
92   *     the original object, or if the hashcodes are different.
93   */
94  public static <T> T reserializeAndAssert(T object) {
95    T copy = reserialize(object);
96    new EqualsTester()
97        .addEqualityGroup(object, copy)
98        .testEquals();
99    Assert.assertEquals(object.getClass(), copy.getClass());
100    return copy;
101  }
102}
103