001/*
002 * Copyright (C) 2007 The Guava Authors
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
017package com.google.common.testing;
018
019import com.google.common.annotations.Beta;
020import com.google.common.annotations.GwtCompatible;
021import junit.framework.Assert;
022import junit.framework.AssertionFailedError;
023
024/**
025 * Tests serialization and deserialization of an object, optionally asserting that the resulting
026 * object is equal to the original.
027 *
028 * <p><b>GWT warning:</b> Under GWT, both methods simply returns their input, as proper GWT
029 * serialization tests require more setup. This no-op behavior allows test authors to intersperse
030 * {@code SerializableTester} calls with other, GWT-compatible tests.
031 *
032 * @author Mike Bostock
033 * @since 10.0
034 */
035@Beta
036@GwtCompatible // but no-op!
037public final class SerializableTester {
038  private SerializableTester() {}
039
040  /**
041   * Serializes and deserializes the specified object.
042   *
043   * <p><b>GWT warning:</b> Under GWT, this method simply returns its input, as proper GWT
044   * serialization tests require more setup. This no-op behavior allows test authors to intersperse
045   * {@code SerializableTester} calls with other, GWT-compatible tests.
046   *
047   * <p>Note that the specified object may not be known by the compiler to be a {@link
048   * java.io.Serializable} instance, and is thus declared an {@code Object}. For example, it might
049   * be declared as a {@code List}.
050   *
051   * @return the re-serialized object
052   * @throws RuntimeException if the specified object was not successfully serialized or
053   *     deserialized
054   */
055  @SuppressWarnings("unchecked")
056  public static <T> T reserialize(T object) {
057    return Platform.reserialize(object);
058  }
059
060  /**
061   * Serializes and deserializes the specified object and verifies that the re-serialized object is
062   * equal to the provided object, that the hashcodes are identical, and that the class of the
063   * re-serialized object is identical to that of the original.
064   *
065   * <p><b>GWT warning:</b> Under GWT, this method simply returns its input, as proper GWT
066   * serialization tests require more setup. This no-op behavior allows test authors to intersperse
067   * {@code SerializableTester} calls with other, GWT-compatible tests.
068   *
069   * <p>Note that the specified object may not be known by the compiler to be a {@link
070   * java.io.Serializable} instance, and is thus declared an {@code Object}. For example, it might
071   * be declared as a {@code List}.
072   *
073   * <p>Note also that serialization is not in general required to return an object that is
074   * {@linkplain Object#equals equal} to the original, nor is it required to return even an object
075   * of the same class. For example, if sublists of {@code MyList} instances were serializable,
076   * those sublists might implement a private {@code MySubList} type but serialize as a plain {@code
077   * MyList} to save space. So long as {@code MyList} has all the public supertypes of {@code
078   * MySubList}, this is safe. For these cases, for which {@code reserializeAndAssert} is too
079   * strict, use {@link #reserialize}.
080   *
081   * @return the re-serialized object
082   * @throws RuntimeException if the specified object was not successfully serialized or
083   *     deserialized
084   * @throws AssertionFailedError if the re-serialized object is not equal to the original object,
085   *     or if the hashcodes are different.
086   */
087  public static <T> T reserializeAndAssert(T object) {
088    T copy = reserialize(object);
089    new EqualsTester().addEqualityGroup(object, copy).testEquals();
090    Assert.assertEquals(object.getClass(), copy.getClass());
091    return copy;
092  }
093}