    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    /**
    035     * Factory to create the identity predicate.
    036     *
    037     * @param <T> the type that the predicate queries
    038     * @param object  the object to compare to
    039     * @return the predicate
    040     */
    041    public static <T> Predicate<T> identityPredicate(final T object) {
    042        if (object == null) {
    043            return NullPredicate.<T>nullPredicate();
    044        }
    045        return new IdentityPredicate<>(object);
    046    }
    047
    048    /** The value to compare to */
    049    private final T iValue;
    050
    051    /**
    052     * Constructor that performs no validation.
    053     * Use {@code identityPredicate} if you want that.
    054     *
    055     * @param object  the object to compare to
    056     */
    057    public IdentityPredicate(final T object) {
    058        iValue = object;
    059    }
    060
    061    /**
    062     * Evaluates the predicate returning true if the input object is identical to
    063     * the stored object.
    064     *
    065     * @param object  the input object
    066     * @return true if input is the same object as the stored value
    067     */
    068    @Override
    069    public boolean evaluate(final T object) {
    070        return iValue == object;
    071    }
    072
    073    /**
    074     * Gets the value.
    075     *
    076     * @return the value
    077     * @since 3.1
    078     */
    079    public T getValue() {
    080        return iValue;
    081    }
    082
    083}