/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.messaging.core.impl;
import org.jboss.jms.delegate.IDBlock;
import org.jboss.logging.Logger;
import org.jboss.messaging.core.contract.MessagingComponent;
import org.jboss.messaging.core.contract.PersistenceManager;
/**
*
* A IDManager.
*
* @author <a href="tim.fox@jboss.com">Tim Fox</a>
* @author <a href="ovidiu@feodorov.com">Ovidiu Feodorov</a>
* @version <tt>$Revision: 2686 $</tt>
*
* $Id: IDManager.java 2686 2007-05-15 08:47:20Z timfox $
*/
public class IDManager implements MessagingComponent
{
// Constants -----------------------------------------------------
private static final Logger log = Logger.getLogger(IDManager.class);
// Static --------------------------------------------------------
// Attributes ----------------------------------------------------
private boolean trace = log.isTraceEnabled();
private boolean started;
private String counterName;
private int bigBlockSize;
private long high;
private long low;
private PersistenceManager pm;
// Constructors --------------------------------------------------
public IDManager(String counterName, int bigBlockSize, PersistenceManager pm) throws Exception
{
this.counterName = counterName;
this.bigBlockSize = bigBlockSize;
this.pm = pm;
}
// MessagingComponent implementation -----------------------------
public synchronized void start() throws Exception
{
getNextBigBlock();
started = true;
}
public synchronized void stop() throws Exception
{
started = false;
}
// Public --------------------------------------------------------
protected void getNextBigBlock() throws Exception
{
low = pm.reserveIDBlock(counterName, bigBlockSize);
high = low + bigBlockSize - 1;
if (trace) { log.trace(this + " retrieved next block of size " + bigBlockSize + " from PersistenceManager, starting at " + low); }
}
public synchronized IDBlock getIDBlock(int size) throws Exception
{
if (!started)
{
throw new IllegalStateException(this + " is not started");
}
if (size <= 0)
{
throw new IllegalArgumentException("block size must be > 0");
}
if (size > bigBlockSize)
{
throw new IllegalArgumentException("block size must be <= bigBlockSize");
}
if (size > high - low + 1)
{
getNextBigBlock();
}
long low = this.low;
this.low += size;
return new IDBlock(low, this.low - 1);
}
public synchronized long getID() throws Exception
{
return getIDBlock(1).getLow();
}
public String toString()
{
return "IDManager[" + counterName + ", " + low + "-" + high + "]";
}
// Package protected ---------------------------------------------
// Protected -----------------------------------------------------
// Private -------------------------------------------------------
// Inner classes -------------------------------------------------
}