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.commons.collections4.functors; 018 019import java.io.Serializable; 020 021import org.apache.commons.collections4.Factory; 022import org.apache.commons.collections4.Transformer; 023 024/** 025 * Transformer implementation that calls a Factory and returns the result. 026 * 027 * @since 3.0 028 * @version $Id: FactoryTransformer.html 972421 2015-11-14 20:00:04Z tn $ 029 */ 030public class FactoryTransformer<I, O> implements Transformer<I, O>, Serializable { 031 032 /** Serial version UID */ 033 private static final long serialVersionUID = -6817674502475353160L; 034 035 /** The factory to wrap */ 036 private final Factory<? extends O> iFactory; 037 038 /** 039 * Factory method that performs validation. 040 * 041 * @param <I> the input type 042 * @param <O> the output type 043 * @param factory the factory to call, not null 044 * @return the <code>factory</code> transformer 045 * @throws IllegalArgumentException if the factory is null 046 */ 047 public static <I, O> Transformer<I, O> factoryTransformer(final Factory<? extends O> factory) { 048 if (factory == null) { 049 throw new IllegalArgumentException("Factory must not be null"); 050 } 051 return new FactoryTransformer<I, O>(factory); 052 } 053 054 /** 055 * Constructor that performs no validation. 056 * Use <code>factoryTransformer</code> if you want that. 057 * 058 * @param factory the factory to call, not null 059 */ 060 public FactoryTransformer(final Factory<? extends O> factory) { 061 super(); 062 iFactory = factory; 063 } 064 065 /** 066 * Transforms the input by ignoring the input and returning the result of 067 * calling the decorated factory. 068 * 069 * @param input the input object to transform 070 * @return the transformed result 071 */ 072 public O transform(final I input) { 073 return iFactory.create(); 074 } 075 076 /** 077 * Gets the factory. 078 * 079 * @return the factory 080 * @since 3.1 081 */ 082 public Factory<? extends O> getFactory() { 083 return iFactory; 084 } 085 086}