Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.collections4.functors; import java.io.Serializable; import org.apache.commons.collections4.Predicate; /** * Predicate implementation that always returns true. * * @since 3.0 * @version $Id: TruePredicate.java 1543950 2013-11-20 21:13:35Z tn $ */ public final class TruePredicate<T> implements Predicate<T>, Serializable { /** Serial version UID */ private static final long serialVersionUID = 3374767158756189740L; /** Singleton predicate instance */ @SuppressWarnings("rawtypes") public static final Predicate INSTANCE = new TruePredicate<Object>(); /** * Factory returning the singleton instance. * * @param <T> the type that the predicate queries * @return the singleton instance * @since 3.1 */ @SuppressWarnings("unchecked") public static <T> Predicate<T> truePredicate() { return (Predicate<T>) INSTANCE; } /** * Restricted constructor. */ private TruePredicate() { super(); } /** * Evaluates the predicate returning true always. * * @param object the input object * @return true always */ public boolean evaluate(final T object) { return true; } private Object readResolve() { return INSTANCE; } }