/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.directory.mitosis.common;


import java.io.Serializable;


/**
 * Represents 'Change Sequence Number' in LDUP specification.
 * 
 * A CSN is a composition of a timestamp, a replica ID and a 
 * operation sequence number.
 * 
 * It distinguishes a change made on an object on a server,
 * and if two operations take place during the same timeStamp,
 * the operation sequence number makes those operations distinct.
 * 
 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
 */
public interface CSN extends Serializable, Comparable
{
    /**
     * Returns GMT timestamp of modification.
     */
    long getTimestamp();


    /**
     * Returns replica ID.
     */
    ReplicaId getReplicaId();


    /**
     * Returns sequence number of modification.
     */
    int getOperationSequence();


    /**
     * Returns octet-string representation of this CSN. 
     */
    String toOctetString();


    /**
     * Returns a byte array representing the CSN
     */
    byte[] toBytes();
}