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  
17  package com.google.common.testing;
18  
19  import com.google.common.annotations.Beta;
20  import com.google.common.annotations.GwtCompatible;
21  
22  import junit.framework.Assert;
23  import 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!
40  public 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 }