    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 * @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     *
    041     * @param <E> the type that the closure acts on
    042     * @param transformer  the transformer to call, null means nop
    043     * @return the {@code transformer} closure
    044     */
    045    public static <E> Closure<E> transformerClosure(final Transformer<? super E, ?> transformer) {
    046        if (transformer == null) {
    047            return NOPClosure.<E>nopClosure();
    048        }
    049        return new TransformerClosure<>(transformer);
    050    }
    051
    052    /** The transformer to wrap */
    053    private final Transformer<? super T, ?> iTransformer;
    054
    055    /**
    056     * Constructor that performs no validation.
    057     * Use {@code transformerClosure} if you want that.
    058     *
    059     * @param transformer  the transformer to call, not null
    060     */
    061    public TransformerClosure(final Transformer<? super T, ?> transformer) {
    062        iTransformer = transformer;
    063    }
    064
    065    /**
    066     * Executes the closure by calling the decorated transformer.
    067     *
    068     * @param input  the input object
    069     */
    070    @Override
    071    public void execute(final T input) {
    072        iTransformer.apply(input);
    073    }
    074
    075    /**
    076     * Gets the transformer.
    077     *
    078     * @return the transformer
    079     * @since 3.1
    080     */
    081    public Transformer<? super T, ?> getTransformer() {
    082        return iTransformer;
    083    }
    084
    085}