001/*
002 * Copyright (C) 2010 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.base;
018
019import com.google.common.annotations.Beta;
020import com.google.common.annotations.GwtCompatible;
021
022/**
023 * Contains static factory methods for creating {@code Equivalence} instances.
024 *
025 * <p>All methods return serializable instances.
026 *
027 * @author Bob Lee
028 * @author Kurt Alfred Kluever
029 * @author Gregory Kick
030 * @since 4.0
031 */
032@Beta
033@GwtCompatible
034public final class Equivalences {
035  private Equivalences() {}
036
037  /**
038   * Returns an equivalence that delegates to {@link Object#equals} and {@link Object#hashCode}.
039   * {@link Equivalence#equivalent} returns {@code true} if both values are null, or if neither
040   * value is null and {@link Object#equals} returns {@code true}. {@link Equivalence#hash} returns
041   * {@code 0} if passed a null value.
042   *
043   * @since 8.0 (present null-friendly behavior)
044   * @since 4.0 (otherwise)
045   * @deprecated This method has been moved to {@link Equivalence#equals}. This method is scheduled
046   *     to be removed in Guava release 14.0.
047   */
048  @Deprecated
049  public static Equivalence<Object> equals() {
050    return Equivalence.Equals.INSTANCE;
051  }
052
053  /**
054   * Returns an equivalence that uses {@code ==} to compare values and {@link
055   * System#identityHashCode(Object)} to compute the hash code.  {@link Equivalence#equivalent}
056   * returns {@code true} if {@code a == b}, including in the case that a and b are both null.
057   *
058   * @deprecated This method has been moved to {@link Equivalence#identity}. This method is schedule
059   *     to be removed in Guava release 14.0.
060   */
061  @Deprecated
062  public static Equivalence<Object> identity() {
063    return Equivalence.Identity.INSTANCE;
064  }
065}