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Commons Collections example source code file (TransformedBag.java)

This example Commons Collections source code file (TransformedBag.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

bag, bag, set, set, transformedbag, transformedbag, transformedcollection, transformer, transformer, util

The Commons Collections TransformedBag.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.bag;

import java.util.Set;

import org.apache.commons.collections.Bag;
import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.collection.TransformedCollection;
import org.apache.commons.collections.set.TransformedSet;

/**
 * Decorates another <code>Bag to transform objects that are added.
 * <p>
 * The add methods are affected by this class.
 * Thus objects must be removed or searched for using their transformed form.
 * For example, if the transformation converts Strings to Integers, you must
 * use the Integer form to remove objects.
 * <p>
 * This class is Serializable from Commons Collections 3.1.
 *
 * @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 TransformedBag
        extends TransformedCollection implements Bag {

    /** Serialization version */
    private static final long serialVersionUID = 5421170911299074185L;

    /**
     * Factory method to create a transforming bag.
     * <p>
     * If there are any elements already in the bag being decorated, they
     * are NOT transformed.
     * 
     * @param bag  the bag to decorate, must not be null
     * @param transformer  the transformer to use for conversion, must not be null
     * @return a new transformed Bag
     * @throws IllegalArgumentException if bag or transformer is null
     */
    public static Bag decorate(Bag bag, Transformer transformer) {
        return new TransformedBag(bag, transformer);
    }
    
    //-----------------------------------------------------------------------
    /**
     * Constructor that wraps (not copies).
     * <p>
     * If there are any elements already in the bag being decorated, they
     * are NOT transformed.
     * 
     * @param bag  the bag to decorate, must not be null
     * @param transformer  the transformer to use for conversion, must not be null
     * @throws IllegalArgumentException if bag or transformer is null
     */
    protected TransformedBag(Bag bag, Transformer transformer) {
        super(bag, transformer);
    }

    /**
     * Gets the decorated bag.
     * 
     * @return the decorated bag
     */
    protected Bag getBag() {
        return (Bag) collection;
    }

    //-----------------------------------------------------------------------
    public int getCount(Object object) {
        return getBag().getCount(object);
    }

    public boolean remove(Object object, int nCopies) {
        return getBag().remove(object, nCopies);
    }

    //-----------------------------------------------------------------------
    public boolean add(Object object, int nCopies) {
        object = transform(object);
        return getBag().add(object, nCopies);
    }

    public Set uniqueSet() {
        Set set = getBag().uniqueSet();
        return TransformedSet.decorate(set, transformer);
    }

}

Other Commons Collections examples (source code examples)

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