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 always returns true.
025 *
026 * @since 3.0
027 */
028public final class TruePredicate<T> implements Predicate<T>, Serializable {
029
030    /** Serial version UID */
031    private static final long serialVersionUID = 3374767158756189740L;
032
033    /** Singleton predicate instance */
034    @SuppressWarnings("rawtypes")
035    public static final Predicate INSTANCE = new TruePredicate<>();
036
037    /**
038     * Factory returning the singleton instance.
039     *
040     * @param <T> the type that the predicate queries
041     * @return the singleton instance
042     * @since 3.1
043     */
044    public static <T> Predicate<T> truePredicate() {
045        return INSTANCE;
046    }
047
048    /**
049     * Restricted constructor.
050     */
051    private TruePredicate() {
052        super();
053    }
054
055    /**
056     * Evaluates the predicate returning true always.
057     *
058     * @param object  the input object
059     * @return true always
060     */
061    @Override
062    public boolean evaluate(final T object) {
063        return true;
064    }
065
066    private Object readResolve() {
067        return INSTANCE;
068    }
069
070}