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}