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Commons Collections example source code file (TransformerClosure.java)

This example Commons Collections source code file (TransformerClosure.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Collections tags/keywords

closure, closure, io, serializable, serializable, transformer, transformer, transformerclosure, transformerclosure

The Commons Collections TransformerClosure.java source code

 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
package org.apache.commons.collections.functors;

import java.io.Serializable;

import org.apache.commons.collections.Closure;
import org.apache.commons.collections.Transformer;

 * Closure implementation that calls a Transformer using the input object
 * and ignore the result.
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
 * @author Stephen Colebourne
public class TransformerClosure implements Closure, Serializable {

    /** Serial version UID */
    private static final long serialVersionUID = -5194992589193388969L;

    /** The transformer to wrap */
    private final Transformer iTransformer;

     * Factory method that performs validation.
     * <p>
     * A null transformer will return the <code>NOPClosure.
     * @param transformer  the transformer to call, null means nop
     * @return the <code>transformer closure
    public static Closure getInstance(Transformer transformer) {
        if (transformer == null) {
            return NOPClosure.INSTANCE;
        return new TransformerClosure(transformer);

     * Constructor that performs no validation.
     * Use <code>getInstance if you want that.
     * @param transformer  the transformer to call, not null
    public TransformerClosure(Transformer transformer) {
        iTransformer = transformer;

     * Executes the closure by calling the decorated transformer.
     * @param input  the input object
    public void execute(Object input) {

     * Gets the transformer.
     * @return the transformer
     * @since Commons Collections 3.1
    public Transformer getTransformer() {
        return iTransformer;


Other Commons Collections examples (source code examples)

Here is a short list of links related to this Commons Collections TransformerClosure.java source code file:

my book on functional programming


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