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