Commons Collections example source code file (ClosureTransformer.java)

This example Commons Collections source code file (ClosureTransformer.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, closuretransformer, closuretransformer, illegalargumentexception, io, object, object, serializable, transformer, transformer

The Commons Collections ClosureTransformer.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;

/**
 * Transformer implementation that calls a Closure using the input object
 * and then returns the input.
 * 
 * @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 ClosureTransformer implements Transformer, Serializable {

    /** Serial version UID */
    private static final long serialVersionUID = 478466901448617286L;

    /** The closure to wrap */
    private final Closure iClosure;

    /**
     * Factory method that performs validation.
     * 
     * @param closure  the closure to call, not null
     * @return the <code>closure transformer
     * @throws IllegalArgumentException if the closure is null
     */
    public static Transformer getInstance(Closure closure) {
        if (closure == null) {
            throw new IllegalArgumentException("Closure must not be null");
        }
        return new ClosureTransformer(closure);
    }

    /**
     * Constructor that performs no validation.
     * Use <code>getInstance if you want that.
     * 
     * @param closure  the closure to call, not null
     */
    public ClosureTransformer(Closure closure) {
        super();
        iClosure = closure;
    }

    /**
     * Transforms the input to result by executing a closure.
     * 
     * @param input  the input object to transform
     * @return the transformed result
     */
    public Object transform(Object input) {
        iClosure.execute(input);
        return input;
    }

    /**
     * Gets the closure.
     * 
     * @return the closure
     * @since Commons Collections 3.1
     */
    public Closure getClosure() {
        return iClosure;
    }

}