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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.codec;
19  
20  /**
21   * <p>Provides the highest level of abstraction for Decoders.
22   * This is the sister interface of {@link Encoder}.  All
23   * Decoders implement this common generic interface.</p>
24   * 
25   * <p>Allows a user to pass a generic Object to any Decoder 
26   * implementation in the codec package.</p>
27   * 
28   * <p>One of the two interfaces at the center of the codec package.</p>
29   * 
30   * @author Apache Software Foundation
31   * @version $Id: Decoder.java 1157192 2011-08-12 17:27:38Z ggregory $
32   */
33  public interface Decoder {
34  
35      /**
36       * Decodes an "encoded" Object and returns a "decoded"
37       * Object.  Note that the implementation of this
38       * interface will try to cast the Object parameter
39       * to the specific type expected by a particular Decoder
40       * implementation.  If a {@link ClassCastException} occurs
41       * this decode method will throw a DecoderException.
42       * 
43       * @param source the object to decode
44       * 
45       * @return a 'decoded" object
46       * 
47       * @throws DecoderException a decoder exception can
48       * be thrown for any number of reasons.  Some good
49       * candidates are that the parameter passed to this
50       * method is null, a param cannot be cast to the
51       * appropriate type for a specific encoder.
52       */
53      Object decode(Object source) throws DecoderException;
54  }  
55