Tomcat example source code file (ReplicatedSession.java)

This example Tomcat source code file (ReplicatedSession.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, io, ioexception, ioexception, manager, object, object, replicatedsession, replicatedsession, security, simpletcpreplicationmanager, simpletcpreplicationmanager, string, stringbuffer, throwable, value

The Tomcat ReplicatedSession.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.ha.session;

/**
 * Title:        Tomcat Session Replication for Tomcat 4.0 <BR>
 * Description:  A very simple straight forward implementation of
 *               session replication of servers in a cluster.<BR>
 *               This session replication is implemented "live". By live
 *               I mean, when a session attribute is added into a session on Node A
 *               a message is broadcasted to other messages and setAttribute is called on the replicated
 *               sessions.<BR>
 *               A full description of this implementation can be found under
 *               <href="http://www.filip.net/tomcat/">Filip's Tomcat Page

 *
 * Copyright:    See apache license
 * @author  Filip Hanik
 * @version $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
 * Description:<BR>
 * The ReplicatedSession class is a simple extension of the StandardSession class
 * It overrides a few methods (setAttribute, removeAttribute, expire, access) and has
 * hooks into the InMemoryReplicationManager to broadcast and receive events from the cluster.<BR>
 * This class inherits the readObjectData and writeObject data methods from the StandardSession
 * and does not contain any serializable elements in addition to the inherited ones from the StandardSession
 *
 */
import org.apache.catalina.Manager;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.Principal;

public class ReplicatedSession extends org.apache.catalina.session.StandardSession
implements org.apache.catalina.ha.ClusterSession{

    private transient Manager mManager = null;
    protected boolean isDirty = false;
    private transient long lastAccessWasDistributed = System.currentTimeMillis();
    private boolean isPrimarySession=true;
    

    public ReplicatedSession(Manager manager) {
        super(manager);
        mManager = manager;
    }


    public boolean isDirty()
    {
        return isDirty;
    }

    public void setIsDirty(boolean dirty)
    {
        isDirty = dirty;
    }


    public void setLastAccessWasDistributed(long time) {
        lastAccessWasDistributed = time;
    }

    public long getLastAccessWasDistributed() {
        return lastAccessWasDistributed;
    }


    public void removeAttribute(String name) {
        setIsDirty(true);
        super.removeAttribute(name);
    }

    /**
     * see parent description,
     * plus we also notify other nodes in the cluster
     */
    public void removeAttribute(String name, boolean notify) {
        setIsDirty(true);
        super.removeAttribute(name,notify);
    }


    /**
     * Sets an attribute and notifies the other nodes in the cluster
     */
    public void setAttribute(String name, Object value)
    {
        if ( value == null ) {
          removeAttribute(name);
          return;
        }
        if (!(value instanceof java.io.Serializable))
            throw new java.lang.IllegalArgumentException("Value for attribute "+name+" is not serializable.");
        setIsDirty(true);
        super.setAttribute(name,value);
    }

    public void setMaxInactiveInterval(int interval) {
        setIsDirty(true);
        super.setMaxInactiveInterval(interval);
    }


    /**
     * Sets the manager for this session
     * @param mgr - the servers InMemoryReplicationManager
     */
    public void setManager(SimpleTcpReplicationManager mgr)
    {
        mManager = mgr;
        super.setManager(mgr);
    }


    /**
     * Set the authenticated Principal that is associated with this Session.
     * This provides an <code>Authenticator with a means to cache a
     * previously authenticated Principal, and avoid potentially expensive
     * <code>Realm.authenticate() calls on every request.
     *
     * @param principal The new Principal, or <code>null if none
     */
    public void setPrincipal(Principal principal) {
        super.setPrincipal(principal);
        setIsDirty(true);
    }

    public void expire() {
        SimpleTcpReplicationManager mgr =(SimpleTcpReplicationManager)getManager();
        mgr.sessionInvalidated(getIdInternal());
        setIsDirty(true);
        super.expire();
    }

    public void invalidate() {
        SimpleTcpReplicationManager mgr =(SimpleTcpReplicationManager)getManager();
        mgr.sessionInvalidated(getIdInternal());
        setIsDirty(true);
        super.invalidate();
    }


    /**
     * Read a serialized version of the contents of this session object from
     * the specified object input stream, without requiring that the
     * StandardSession itself have been serialized.
     *
     * @param stream The object input stream to read from
     *
     * @exception ClassNotFoundException if an unknown class is specified
     * @exception IOException if an input/output error occurs
     */
    public void readObjectData(ObjectInputStream stream)
        throws ClassNotFoundException, IOException {

        super.readObjectData(stream);

    }


    /**
     * Write a serialized version of the contents of this session object to
     * the specified object output stream, without requiring that the
     * StandardSession itself have been serialized.
     *
     * @param stream The object output stream to write to
     *
     * @exception IOException if an input/output error occurs
     */
    public void writeObjectData(ObjectOutputStream stream)
        throws IOException {

        super.writeObjectData(stream);

    }
    
    public void setId(String id, boolean tellNew) {

        if ((this.id != null) && (manager != null))
            manager.remove(this);

        this.id = id;

        if (manager != null)
            manager.add(this);
        if (tellNew) tellNew();
    }
    
    






    /**
     * returns true if this session is the primary session, if that is the
     * case, the manager can expire it upon timeout.
     */
    public boolean isPrimarySession() {
        return isPrimarySession;
    }

    /**
     * Sets whether this is the primary session or not.
     * @param primarySession Flag value
     */
    public void setPrimarySession(boolean primarySession) {
        this.isPrimarySession=primarySession;
    }




    /**
     * Implements a log method to log through the manager
     */
    protected void log(String message) {

        if ((mManager != null) && (mManager instanceof SimpleTcpReplicationManager)) {
            ((SimpleTcpReplicationManager) mManager).log.debug("ReplicatedSession: " + message);
        } else {
            System.out.println("ReplicatedSession: " + message);
        }

    }

    protected void log(String message, Throwable x) {

        if ((mManager != null) && (mManager instanceof SimpleTcpReplicationManager)) {
            ((SimpleTcpReplicationManager) mManager).log.error("ReplicatedSession: " + message,x);
        } else {
            System.out.println("ReplicatedSession: " + message);
            x.printStackTrace();
        }

    }

    public String toString() {
        StringBuffer buf = new StringBuffer("ReplicatedSession id=");
        buf.append(getIdInternal()).append(" ref=").append(super.toString()).append("\n");
        java.util.Enumeration e = getAttributeNames();
        while ( e.hasMoreElements() ) {
            String name = (String)e.nextElement();
            Object value = getAttribute(name);
            buf.append("\tname=").append(name).append("; value=").append(value).append("\n");
        }
        buf.append("\tLastAccess=").append(getLastAccessedTime()).append("\n");
        return buf.toString();
    }
    public int getAccessCount() {
        return accessCount.get();
    }
    public void setAccessCount(int accessCount) {
        this.accessCount.set(accessCount);
    }
    public long getLastAccessedTime() {
        return lastAccessedTime;
    }
    public void setLastAccessedTime(long lastAccessedTime) {
        this.lastAccessedTime = lastAccessedTime;
    }
    public long getThisAccessedTime() {
        return thisAccessedTime;
    }
    public void setThisAccessedTime(long thisAccessedTime) {
        this.thisAccessedTime = thisAccessedTime;
    }

}