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.function.Predicate;
020
021import org.apache.camel.util.ObjectHelper;
022
023/**
024 * Predicate helpers, inspired by http://minborgsjavapot.blogspot.it/2016/03/put-your-java-8-method-references-to.html
025 *
026 */
027public final class Predicates {
028    private Predicates() {
029    }
030
031    /**
032     * Wrap a predicate, useful for method references.
033     */
034    public static <T> Predicate<T> of(Predicate<T> predicate) {
035        ObjectHelper.notNull(predicate, "Predicate");
036
037        return predicate;
038    }
039
040
041    /**
042     * Negates a predicate, useful for method references.
043     * 
044     * <pre>
045     *     Stream.of("A", "", "B")
046     *         .filter(Predicates.negate(String::isEmpty))
047     *         .count();
048     * </pre>
049     */
050    public static <T> Predicate<T> negate(Predicate<T> predicate) {
051        ObjectHelper.notNull(predicate, "Predicate");
052
053        return predicate.negate();
054    }
055}