001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.functors;
018
019import java.io.Serializable;
020
021import org.apache.commons.collections4.Predicate;
022
023/**
024 * Predicate implementation that returns true if the input is the same object
025 * as the one stored in this predicate.
026 *
027 * @since 3.0
028 */
029public final class IdentityPredicate<T> implements Predicate<T>, Serializable {
030
031    /** Serial version UID */
032    private static final long serialVersionUID = -89901658494523293L;
033
034    /** The value to compare to */
035    private final T iValue;
036
037    /**
038     * Factory to create the identity predicate.
039     *
040     * @param <T> the type that the predicate queries
041     * @param object  the object to compare to
042     * @return the predicate
043     */
044    public static <T> Predicate<T> identityPredicate(final T object) {
045        if (object == null) {
046            return NullPredicate.<T>nullPredicate();
047        }
048        return new IdentityPredicate<>(object);
049    }
050
051    /**
052     * Constructor that performs no validation.
053     * Use <code>identityPredicate</code> if you want that.
054     *
055     * @param object  the object to compare to
056     */
057    public IdentityPredicate(final T object) {
058        super();
059        iValue = object;
060    }
061
062    /**
063     * Evaluates the predicate returning true if the input object is identical to
064     * the stored object.
065     *
066     * @param object  the input object
067     * @return true if input is the same object as the stored value
068     */
069    @Override
070    public boolean evaluate(final T object) {
071        return iValue == object;
072    }
073
074    /**
075     * Gets the value.
076     *
077     * @return the value
078     * @since 3.1
079     */
080    public T getValue() {
081        return iValue;
082    }
083
084}