001    /*
002     *  Licensed to the Apache Software Foundation (ASF) under one
003     *  or more contributor license agreements.  See the NOTICE file
004     *  distributed with this work for additional information
005     *  regarding copyright ownership.  The ASF licenses this file
006     *  to you under the Apache License, Version 2.0 (the
007     *  "License"); you may not use this file except in compliance
008     *  with the License.  You may obtain a copy of the License at
009     *  
010     *    http://www.apache.org/licenses/LICENSE-2.0
011     *  
012     *  Unless required by applicable law or agreed to in writing,
013     *  software distributed under the License is distributed on an
014     *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     *  KIND, either express or implied.  See the License for the
016     *  specific language governing permissions and limitations
017     *  under the License. 
018     *  
019     */
020    package org.apache.directory.shared.ldap.codec.controls;
021    
022    import java.nio.ByteBuffer;
023    
024    import org.apache.directory.shared.asn1.codec.EncoderException;
025    
026    /**
027     * Define the transform method to be implemented by all the codec Controls
028     *
029     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
030     * @version $Rev$, $Date$
031     */
032    public interface CodecControl
033    {
034        /**
035         * Generate the PDU which contains the Control.
036         * <pre> 
037         * Control : 
038         * 
039         * 0x30 LL
040         *   0x04 LL type 
041         *   [0x01 0x01 criticality]
042         *   [0x04 LL value]
043         * </pre>
044         * @param buffer The encoded PDU
045         * @return A ByteBuffer that contaons the PDU
046         * @throws EncoderException If anything goes wrong.
047         */
048        ByteBuffer encode( ByteBuffer buffer ) throws EncoderException;
049    
050        
051        /**
052         * Compute the Control length
053         * <pre> 
054         * Control :
055         * 
056         * 0x30 L1
057         *  |
058         *  +--> 0x04 L2 controlType
059         * [+--> 0x01 0x01 criticality]
060         * [+--> 0x04 L3 controlValue] 
061         * 
062         * Control length = Length(0x30) + length(L1) 
063         *                  + Length(0x04) + Length(L2) + L2
064         *                  [+ Length(0x01) + 1 + 1]
065         *                  [+ Length(0x04) + Length(L3) + L3]
066         * </pre>
067         */
068        int computeLength();
069    
070        /**
071         * Get the associated decoder
072         *
073         * @return The Control decoder
074         */
075        ControlDecoder getDecoder();
076    }