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}