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.camel.util.function;
018
019import java.util.Objects;
020import java.util.function.Predicate;
021
022/**
023 * Predicate helpers, inspired by http://minborgsjavapot.blogspot.it/2016/03/put-your-java-8-method-references-to.html
024 *
025 */
026public final class Predicates {
027    private Predicates() {
028    }
029
030    /**
031     * Wrap a predicate, useful for method references.
032     */
033    public static <T> Predicate<T> of(Predicate<T> predicate) {
034        Objects.requireNonNull(predicate, "Predicate must be specified");
035
036        return predicate;
037    }
038
039    /**
040     * Negates a predicate, useful for method references.
041     * 
042     * <pre>
043     * Stream.of("A", "", "B")
044     *         .filter(Predicates.negate(String::isEmpty))
045     *         .count();
046     * </pre>
047     */
048    public static <T> Predicate<T> negate(Predicate<T> predicate) {
049        Objects.requireNonNull(predicate, "Predicate must be specified");
050
051        return predicate.negate();
052    }
053}