xref: /external/apache-http/src/org/apache/commons/codec/Decoder.java

/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed 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.codec;

/**
 * <p>Provides the highest level of abstraction for Decoders.
 * This is the sister interface of {@link Encoder}.  All
 * Decoders implement this common generic interface.</p>
 *
 * <p>Allows a user to pass a generic Object to any Decoder
 * implementation in the codec package.</p>
 *
 * <p>One of the two interfaces at the center of the codec package.</p>
 *
 * @author Apache Software Foundation
 * @version $Id: Decoder.java,v 1.9 2004/02/29 04:08:31 tobrien Exp $
 */
public interface Decoder {

    /**
     * Decodes an "encoded" Object and returns a "decoded"
     * Object.  Note that the implementation of this
     * interface will try to cast the Object parameter
     * to the specific type expected by a particular Decoder
     * implementation.  If a {@link java.lang.ClassCastException} occurs
     * this decode method will throw a DecoderException.
     *
     * @param pObject an object to "decode"
     *
     * @return a 'decoded" object
     *
     * @throws DecoderException a decoder exception can
     * be thrown for any number of reasons.  Some good
     * candidates are that the parameter passed to this
     * method is null, a param cannot be cast to the
     * appropriate type for a specific encoder.
     */
    Object decode(Object pObject) throws DecoderException;
}