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 *      https://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 * Closure implementation that calls a Transformer using the input object
026 * and ignore the result.
027 *
028 * @param <T> The type of the input to the operation.
029 * @since 3.0
030 */
031public class TransformerClosure<T> implements Closure<T>, Serializable {
032
033    /** Serial version UID */
034    private static final long serialVersionUID = -5194992589193388969L;
035
036    /**
037     * Factory method that performs validation.
038     * <p>
039     * A null transformer will return the {@code NOPClosure}.
040     * </p>
041     *
042     * @param <E> The type that the closure acts on
043     * @param transformer  The transformer to call, null means nop
044     * @return The {@code transformer} closure
045     */
046    public static <E> Closure<E> transformerClosure(final Transformer<? super E, ?> transformer) {
047        if (transformer == null) {
048            return NOPClosure.<E>nopClosure();
049        }
050        return new TransformerClosure<>(transformer);
051    }
052
053    /** The transformer to wrap */
054    private final Transformer<? super T, ?> iTransformer;
055
056    /**
057     * Constructor that performs no validation.
058     * Use {@code transformerClosure} if you want that.
059     *
060     * @param transformer  The transformer to call, not null
061     */
062    public TransformerClosure(final Transformer<? super T, ?> transformer) {
063        iTransformer = transformer;
064    }
065
066    /**
067     * Executes the closure by calling the decorated transformer.
068     *
069     * @param input  The input object
070     */
071    @Override
072    public void execute(final T input) {
073        iTransformer.apply(input);
074    }
075
076    /**
077     * Gets the transformer.
078     *
079     * @return The transformer
080     * @since 3.1
081     */
082    public Transformer<? super T, ?> getTransformer() {
083        return iTransformer;
084    }
085
086}