    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 *      https://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 */
    017
    018package org.apache.commons.lang3.function;
    019
    020import java.util.function.Predicate;
    021
    022/**
    023 * Factory for {@link Predicate}.
    024 *
    025 * @since 3.18.0
    026 */
    027public class Predicates {
    028
    029    private static final Predicate<?> TRUE = t -> true;
    030    private static final Predicate<?> FALSE = t -> false;
    031
    032    /**
    033     * Gets the Predicate singleton that always returns false.
    034     *
    035     * @param <T> the type of the input to the predicate.
    036     * @return the Predicate singleton.
    037     */
    038    @SuppressWarnings("unchecked")
    039    // method name cannot be "false".
    040    public static <T> Predicate<T> falsePredicate() {
    041        return (Predicate<T>) FALSE;
    042    }
    043
    044    /**
    045     * Gets the Predicate singleton that always returns true.
    046     *
    047     * @param <T> the type of the input to the predicate.
    048     * @return the Predicate singleton.
    049     */
    050    @SuppressWarnings("unchecked")
    051    // method name cannot be "true".
    052    public static <T> Predicate<T> truePredicate() {
    053        return (Predicate<T>) TRUE;
    054    }
    055
    056    /**
    057     * No instances needed.
    058     */
    059    private Predicates() {
    060        // empty
    061    }
    062}