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 {
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")
reserialize(T object)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    */
reserializeAndAssert(T object)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