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.Closure; 023import org.apache.commons.collections4.Transformer; 024 025/** 026 * Transformer implementation that calls a Closure using the input object 027 * and then returns the input. 028 * 029 * @since 3.0 030 */ 031public class ClosureTransformer<T> implements Transformer<T, T>, Serializable { 032 033 /** Serial version UID */ 034 private static final long serialVersionUID = 478466901448617286L; 035 036 /** 037 * Factory method that performs validation. 038 * 039 * @param <T> the type of the object to transform 040 * @param closure the closure to call, not null 041 * @return the {@code closure} transformer 042 * @throws NullPointerException if the closure is null 043 */ 044 public static <T> Transformer<T, T> closureTransformer(final Closure<? super T> closure) { 045 return new ClosureTransformer<>(Objects.requireNonNull(closure, "closure")); 046 } 047 048 /** The closure to wrap */ 049 private final Closure<? super T> iClosure; 050 051 /** 052 * Constructor that performs no validation. 053 * Use {@code closureTransformer} if you want that. 054 * 055 * @param closure the closure to call, not null 056 */ 057 public ClosureTransformer(final Closure<? super T> closure) { 058 iClosure = closure; 059 } 060 061 /** 062 * Gets the closure. 063 * 064 * @return the closure 065 * @since 3.1 066 */ 067 public Closure<? super T> getClosure() { 068 return iClosure; 069 } 070 071 /** 072 * Transforms the input to result by executing a closure. 073 * 074 * @param input the input object to transform 075 * @return the transformed result 076 */ 077 @Override 078 public T transform(final T input) { 079 iClosure.execute(input); 080 return input; 081 } 082 083}