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.Closure;
022import org.apache.commons.collections4.Transformer;
023
024/**
025 * Transformer implementation that calls a Closure using the input object
026 * and then returns the input.
027 *
028 * @since 3.0
029 * @version $Id: ClosureTransformer.html 972421 2015-11-14 20:00:04Z tn $
030 */
031public class ClosureTransformer<T> implements Transformer<T, T>, Serializable {
032
033    /** Serial version UID */
034    private static final long serialVersionUID = 478466901448617286L;
035
036    /** The closure to wrap */
037    private final Closure<? super T> iClosure;
038
039    /**
040     * Factory method that performs validation.
041     *
042     * @param <T>  the type of the object to transform
043     * @param closure  the closure to call, not null
044     * @return the <code>closure</code> transformer
045     * @throws IllegalArgumentException if the closure is null
046     */
047    public static <T> Transformer<T, T> closureTransformer(final Closure<? super T> closure) {
048        if (closure == null) {
049            throw new IllegalArgumentException("Closure must not be null");
050        }
051        return new ClosureTransformer<T>(closure);
052    }
053
054    /**
055     * Constructor that performs no validation.
056     * Use <code>closureTransformer</code> if you want that.
057     *
058     * @param closure  the closure to call, not null
059     */
060    public ClosureTransformer(final Closure<? super T> closure) {
061        super();
062        iClosure = closure;
063    }
064
065    /**
066     * Transforms the input to result by executing a closure.
067     *
068     * @param input  the input object to transform
069     * @return the transformed result
070     */
071    public T transform(final T input) {
072        iClosure.execute(input);
073        return input;
074    }
075
076    /**
077     * Gets the closure.
078     *
079     * @return the closure
080     * @since 3.1
081     */
082    public Closure<? super T> getClosure() {
083        return iClosure;
084    }
085
086}