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 throws an exception if the input is null. 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 NullIsExceptionPredicate implements Predicate, PredicateDecorator, Serializable { 033 034 /** Serial version UID */ 035 private static final long serialVersionUID = 3243449850504576071L; 036 037 /** The predicate to decorate */ 038 private final Predicate iPredicate; 039 040 /** 041 * Factory to create the null exception predicate. 042 * 043 * @param predicate the predicate to decorate, not null 044 * @return the predicate 045 * @throws IllegalArgumentException if the predicate is null 046 */ 047 public static Predicate getInstance(Predicate predicate) { 048 if (predicate == null) { 049 throw new IllegalArgumentException("Predicate must not be null"); 050 } 051 return new NullIsExceptionPredicate(predicate); 052 } 053 054 /** 055 * Constructor that performs no validation. 056 * Use <code>getInstance</code> if you want that. 057 * 058 * @param predicate the predicate to call after the null check 059 */ 060 public NullIsExceptionPredicate(Predicate predicate) { 061 super(); 062 iPredicate = predicate; 063 } 064 065 /** 066 * Evaluates the predicate returning the result of the decorated predicate 067 * once a null check is performed. 068 * 069 * @param object the input object 070 * @return true if decorated predicate returns true 071 * @throws FunctorException if input is null 072 */ 073 public boolean evaluate(Object object) { 074 if (object == null) { 075 throw new FunctorException("Input Object must not be null"); 076 } 077 return iPredicate.evaluate(object); 078 } 079 080 /** 081 * Gets the predicate being decorated. 082 * 083 * @return the predicate as the only element in an array 084 * @since Commons Collections 3.1 085 */ 086 public Predicate[] getPredicates() { 087 return new Predicate[] {iPredicate}; 088 } 089 090 }