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    
018    package org.apache.commons.codec;
019    
020    /**
021     * <p>Provides the highest level of abstraction for Decoders.
022     * This is the sister interface of {@link Encoder}.  All
023     * Decoders implement this common generic interface.</p>
024     * 
025     * <p>Allows a user to pass a generic Object to any Decoder 
026     * implementation in the codec package.</p>
027     * 
028     * <p>One of the two interfaces at the center of the codec package.</p>
029     * 
030     * @author Apache Software Foundation
031     * @version $Id: Decoder.java 797690 2009-07-24 23:28:35Z ggregory $
032     */
033    public interface Decoder {
034    
035        /**
036         * Decodes an "encoded" Object and returns a "decoded"
037         * Object.  Note that the implementation of this
038         * interface will try to cast the Object parameter
039         * to the specific type expected by a particular Decoder
040         * implementation.  If a {@link ClassCastException} occurs
041         * this decode method will throw a DecoderException.
042         * 
043         * @param pObject an object to "decode"
044         * 
045         * @return a 'decoded" object
046         * 
047         * @throws DecoderException a decoder exception can
048         * be thrown for any number of reasons.  Some good
049         * candidates are that the parameter passed to this
050         * method is null, a param cannot be cast to the
051         * appropriate type for a specific encoder.
052         */
053        Object decode(Object pObject) throws DecoderException;
054    }  
055