    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}