Tomcat example source code file (ReplicatedMapEntry.java)

This example Tomcat source code file (ReplicatedMapEntry.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

classnotfoundexception, classnotfoundexception, io, ioexception, ioexception, replicatedmapentry, replicatedmapentry, serializable, serializable

The Tomcat ReplicatedMapEntry.java source code

/*
 * 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.catalina.tribes.tipis;

import java.io.IOException;
import java.io.Serializable;

/**
 * 
 * For smarter replication, an object can implement this interface to replicate diffs<br>
 * The replication logic will call the methods in the following order:<br>
 * <code>
 * 1. if ( entry.isDirty() ) <br>
 *      try {
 * 2.     entry.lock();<br>
 * 3.     byte[] diff = entry.getDiff();<br>
 * 4.     entry.reset();<br>
 *      } finally {<br>
 * 5.     entry.unlock();<br>
 *      }<br>
 *    }<br>
 * </code>
 * <br>
 * <br>
 * When the data is deserialized the logic is called in the following order<br>
 * <code>
 * 1. ReplicatedMapEntry entry = (ReplicatedMapEntry)objectIn.readObject();<br>
 * 2. if ( isBackup(entry)||isPrimary(entry) ) entry.setOwner(owner); <br>
 * </code>
 * <br>
 * 
 * 
 * @author Filip Hanik
 * @version 1.0
 */
public interface ReplicatedMapEntry extends Serializable {
    
    /**
     * Has the object changed since last replication
     * and is not in a locked state
     * @return boolean
     */
    public boolean isDirty();
    
    /**
     * If this returns true, the map will extract the diff using getDiff()
     * Otherwise it will serialize the entire object.
     * @return boolean
     */
    public boolean isDiffable();
    
    /**
     * Returns a diff and sets the dirty map to false
     * @return byte[]
     * @throws IOException
     */
    public byte[] getDiff() throws IOException;
    
    
    /**
     * Applies a diff to an existing object.
     * @param diff byte[]
     * @param offset int
     * @param length int
     * @throws IOException
     */
    public void applyDiff(byte[] diff, int offset, int length) throws IOException, ClassNotFoundException;
    
    /**
     * Resets the current diff state and resets the dirty flag
     */
    public void resetDiff();
    
    /**
     * Lock during serialization
     */
    public void lock();
    
    /**
     * Unlock after serialization
     */
    public void unlock();
    
    /**
     * This method is called after the object has been 
     * created on a remote map. On this method,
     * the object can initialize itself for any data that wasn't 
     * 
     * @param owner Object
     */
    public void setOwner(Object owner);
    
    /**
     * For accuracy checking, a serialized attribute can contain a version number
     * This number increases as modifications are made to the data.
     * The replicated map can use this to ensure accuracy on a periodic basis
     * @return long - the version number or -1 if the data is not versioned
     */
    public long getVersion();
    
    /**
     * Forces a certain version to a replicated map entry<br>
     * @param version long
     */
    public void setVersion(long version);
    
    
    
    
}