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 */ 017 package org.apache.commons.collections.functors; 018 019 import java.io.Serializable; 020 021 import org.apache.commons.collections.FunctorException; 022 import org.apache.commons.collections.Predicate; 023 024 /** 025 * Predicate implementation that always throws an exception. 026 * 027 * @since Commons Collections 3.0 028 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 029 * 030 * @author Stephen Colebourne 031 */ 032 public final class ExceptionPredicate implements Predicate, Serializable { 033 034 /** Serial version UID */ 035 private static final long serialVersionUID = 7179106032121985545L; 036 037 /** Singleton predicate instance */ 038 public static final Predicate INSTANCE = new ExceptionPredicate(); 039 040 /** 041 * Factory returning the singleton instance. 042 * 043 * @return the singleton instance 044 * @since Commons Collections 3.1 045 */ 046 public static Predicate getInstance() { 047 return INSTANCE; 048 } 049 050 /** 051 * Restricted constructor. 052 */ 053 private ExceptionPredicate() { 054 super(); 055 } 056 057 /** 058 * Evaluates the predicate always throwing an exception. 059 * 060 * @param object the input object 061 * @return never 062 * @throws FunctorException always 063 */ 064 public boolean evaluate(Object object) { 065 throw new FunctorException("ExceptionPredicate invoked"); 066 } 067 068 }