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
018package 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 */
033public 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