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