/*
* JBoss, Home of Professional Open Source
* Copyright 2007, Red Hat Middleware LLC, 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.ejb3.cache.impl;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.ejb.NoSuchEJBException;
import org.jboss.ejb3.cache.Identifiable;
import org.jboss.ejb3.cache.ObjectStore;
import org.jboss.ejb3.cache.PassivatingCache;
import org.jboss.ejb3.cache.PassivationManager;
import org.jboss.ejb3.cache.StatefulObjectFactory;
import org.jboss.logging.Logger;
/**
* Comment
*
* @author <a href="mailto:carlo.dewolf@jboss.com">Carlo de Wolf</a>
* @version $Revision: $
*/
public class SimplePassivatingCache<T extends Identifiable & Serializable> implements PassivatingCache<T>
{
private static final Logger log = Logger.getLogger(SimplePassivatingCache.class);
private StatefulObjectFactory<T> factory;
private PassivationManager<T> passivationManager;
private ObjectStore<T> store;
private Map<Object, Entry> cache;
private int sessionTimeout = -1;
private String name;
private Thread sessionTimeoutTask;
private static enum EntryState { READY, IN_USE };
private class Entry
{
long lastUsed;
T obj;
EntryState state;
Entry(T obj)
{
assert obj != null : "obj is null";
this.lastUsed = System.currentTimeMillis();
this.obj = obj;
this.state = EntryState.IN_USE;
}
}
private class SessionTimeoutThread extends Thread
{
public SessionTimeoutThread(String name)
{
super(name);
setDaemon(true);
}
@Override
public void run()
{
try
{
while(!Thread.currentThread().isInterrupted())
{
Thread.sleep(1000);
synchronized (cache)
{
if(Thread.currentThread().isInterrupted())
return;
long then = System.currentTimeMillis() - sessionTimeout * 1000;
Iterator<Entry> it = cache.values().iterator();
while(it.hasNext())
{
Entry entry = it.next();
if(then >= entry.lastUsed && entry.state != EntryState.IN_USE)
{
// TODO: can passivate?
passivationManager.prePassivate(entry.obj);
store.store(entry.obj);
it.remove();
}
}
}
}
}
catch(InterruptedException e)
{
// do nothing
}
}
}
public SimplePassivatingCache(StatefulObjectFactory<T> factory, PassivationManager<T> passivationManager, ObjectStore<T> store)
{
assert factory != null : "factory is null";
assert passivationManager != null : "passivationManager is null";
assert store != null : "store is null";
this.factory = factory;
this.passivationManager = passivationManager;
this.store = store;
this.cache = new HashMap<Object, Entry>();
}
public T create(Class<?>[] initTypes, Object[] initValues)
{
T obj = factory.create(initTypes, initValues);
Entry entry = new Entry(obj);
synchronized (cache)
{
cache.put(obj.getId(), entry);
}
return obj;
}
public T get(Object key) throws NoSuchEJBException
{
synchronized (cache)
{
Entry entry = cache.get(key);
if(entry == null)
{
T obj = store.load(key);
if(obj != null)
{
passivationManager.postActivate(obj);
entry = new Entry(obj);
cache.put(key, entry);
return entry.obj;
}
}
if(entry == null)
throw new NoSuchEJBException(String.valueOf(key));
if(entry.state != EntryState.READY)
throw new IllegalStateException("entry " + entry + " is not ready");
entry.state = EntryState.IN_USE;
entry.lastUsed = System.currentTimeMillis();
return entry.obj;
}
}
public T peek(Object key) throws NoSuchEJBException
{
synchronized (cache)
{
Entry entry = cache.get(key);
if(entry == null)
{
T obj = store.load(key);
if(obj != null)
{
passivationManager.postActivate(obj);
entry = new Entry(obj);
cache.put(key, entry);
}
}
entry.state = EntryState.READY;
if(entry == null)
throw new NoSuchEJBException(String.valueOf(key));
return entry.obj;
}
}
public void release(T obj)
{
synchronized (cache)
{
Entry entry = cache.get(obj.getId());
if(entry.state != EntryState.IN_USE)
throw new IllegalStateException("entry " + entry + " is not in use");
entry.state = EntryState.READY;
entry.lastUsed = System.currentTimeMillis();
}
}
public void remove(Object key)
{
Entry entry;
synchronized (cache)
{
entry = cache.remove(key);
if(entry.state != EntryState.READY)
throw new IllegalStateException("entry " + entry + " is not ready");
}
if(entry != null)
factory.destroy(entry.obj);
}
public void setName(String name)
{
this.name = name;
}
public void setSessionTimeout(int sessionTimeout)
{
assert sessionTimeout >= 0 : "sessionTimeout must be >= 0";
this.sessionTimeout = sessionTimeout;
}
public void start()
{
assert name != null : "name has not been set";
assert sessionTimeout != -1 : "sessionTimeout has not been set";
if(sessionTimeout > 0)
{
sessionTimeoutTask = new SessionTimeoutThread("Passivation Thread - " + name);
sessionTimeoutTask.start();
}
}
public void stop()
{
if(sessionTimeoutTask != null)
{
sessionTimeoutTask.interrupt();
try
{
sessionTimeoutTask.join(5000);
}
catch (InterruptedException e)
{
// ignore
}
if(sessionTimeoutTask.isAlive())
log.warn("Failed to stop " + sessionTimeoutTask);
}
}
}