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     */
017    package org.apache.commons.collections.buffer;
018    
019    import org.apache.commons.collections.Buffer;
020    import org.apache.commons.collections.Transformer;
021    import org.apache.commons.collections.collection.TransformedCollection;
022    
023    /**
024     * Decorates another <code>Buffer</code> to transform objects that are added.
025     * <p>
026     * The add methods are affected by this class.
027     * Thus objects must be removed or searched for using their transformed form.
028     * For example, if the transformation converts Strings to Integers, you must
029     * use the Integer form to remove objects.
030     * <p>
031     * This class is Serializable from Commons Collections 3.1.
032     *
033     * @since Commons Collections 3.0
034     * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
035     * 
036     * @author Stephen Colebourne
037     */
038    public class TransformedBuffer extends TransformedCollection implements Buffer {
039    
040        /** Serialization version */
041        private static final long serialVersionUID = -7901091318986132033L;
042    
043        /**
044         * Factory method to create a transforming buffer.
045         * <p>
046         * If there are any elements already in the buffer being decorated, they
047         * are NOT transformed.
048         * 
049         * @param buffer  the buffer to decorate, must not be null
050         * @param transformer  the transformer to use for conversion, must not be null
051         * @return a new transformed Buffer
052         * @throws IllegalArgumentException if buffer or transformer is null
053         */
054        public static Buffer decorate(Buffer buffer, Transformer transformer) {
055            return new TransformedBuffer(buffer, transformer);
056        }
057        
058        //-----------------------------------------------------------------------
059        /**
060         * Constructor that wraps (not copies).
061         * <p>
062         * If there are any elements already in the buffer being decorated, they
063         * are NOT transformed.
064         * 
065         * @param buffer  the buffer to decorate, must not be null
066         * @param transformer  the transformer to use for conversion, must not be null
067         * @throws IllegalArgumentException if buffer or transformer is null
068         */
069        protected TransformedBuffer(Buffer buffer, Transformer transformer) {
070            super(buffer, transformer);
071        }
072    
073        /**
074         * Gets the decorated buffer.
075         * 
076         * @return the decorated buffer
077         */
078        protected Buffer getBuffer() {
079            return (Buffer) collection;
080        }
081    
082        //-----------------------------------------------------------------------
083        public Object get() {
084            return getBuffer().get();
085        }
086    
087        public Object remove() {
088            return getBuffer().remove();
089        }
090    
091    }