/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file 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.mx.interceptor;
import java.util.Arrays;
import javax.management.Descriptor;
import javax.management.InvalidAttributeValueException;
import javax.management.ObjectName;
import org.jboss.mx.modelmbean.ModelMBeanConstants;
import org.jboss.mx.server.Invocation;
/** This interceptor handles the ModelMBean operation caching
*
* @author <a href="mailto:adrian@jboss.org">Adrian Brock</a>.
* @author Scott.Stark@jboss.org
* @version $Revision: 81026 $
*/
public class ModelMBeanOperationInterceptor
extends AbstractInterceptor
implements ModelMBeanConstants
{
// Constants -----------------------------------------------------
// Attributes ----------------------------------------------------
private boolean trace;
// Constructors --------------------------------------------------
public ModelMBeanOperationInterceptor()
{
super("ModelMBean Operation Interceptor");
trace = log.isTraceEnabled();
}
// Public --------------------------------------------------------
public Object invoke(Invocation invocation) throws Throwable
{
// get the operation's descriptor
Descriptor d = invocation.getDescriptor();
Class clazz = invocation.getReturnTypeClass();
String name = null;
ObjectName objectName = null;
if (trace)
{
if (d != null)
name = (String) d.getFieldValue(NAME);
objectName = invocation.getInvoker().getObjectName();
}
if (trace)
{
Object args = invocation.getArgs();
if (args != null)
args = Arrays.asList((Object[]) args);
log.trace("Invoking objectName=" + objectName + " oper=" + name + " args=" + args + " desc=" + d);
}
long limit = CACHE_NEVER_LIMIT;
if (d != null && clazz != null)
{
String timeLimit = (String) d.getFieldValue(CURRENCY_TIME_LIMIT);
if (timeLimit != null)
limit = Long.parseLong(timeLimit);
// We are never stale
if (limit == CACHE_ALWAYS_LIMIT)
{
String timeStamp = (String)d.getFieldValue(LAST_UPDATED_TIME_STAMP);
if (timeStamp != null)
{
Object value = d.getFieldValue(CACHED_VALUE);
if (trace)
log.trace("Always cache objectName=" + objectName + " oper=" + name + " value=" + value);
checkAssignable("Cached value in descriptor ", clazz, value);
return value;
}
}
// is caching enabled
if (limit != CACHE_NEVER_LIMIT)
{
String timeStamp = (String) d.getFieldValue(LAST_UPDATED_TIME_STAMP);
long lastUpdate = (timeStamp == null) ? 0 : Long.parseLong(timeStamp);
// if the value hasn't gone stale, return from the descriptor
long now = System.currentTimeMillis();
long expires = lastUpdate * 1000 + limit * 1000;
if (now < expires)
{
Object value = d.getFieldValue(CACHED_VALUE);
if (trace)
log.trace("Using cache objectName=" + objectName + " oper=" + name + " value=" + value + " now=" + now + " expires=" + expires);
checkAssignable("Cached value in descriptor ", clazz, value);
return value;
}
else
{
if (trace)
log.trace("Cache expired objectName=" + objectName + " oper=" + name + " now=" + now + " expires=" + expires);
d.removeField(CACHED_VALUE);
}
}
else
{
// Unfortunatley we have to cope with stupid users
if (trace)
log.trace("Removing any cached value objectName=" + objectName + " oper=" + name + " descriptor=" + d);
d.removeField(CACHED_VALUE);
}
}
// we got here means either stale value in descriptior, or no caching
Object value = invocation.invoke();
if (trace)
log.trace("Got result objectName=" + objectName + " oper=" + name + " value=" + value);
// update the descriptor (unless not caching)
if (d !=null && limit != CACHE_NEVER_LIMIT)
{
String timestamp = Long.toString(System.currentTimeMillis()/1000);
if (trace)
log.trace("Cache result objectName=" + objectName + " oper=" + name + " value=" + value + " timestamp=" + timestamp);
d.setField(CACHED_VALUE, value);
d.setField(LAST_UPDATED_TIME_STAMP, timestamp);
}
return value;
}
protected void checkAssignable(String context, Class clazz, Object value) throws InvalidAttributeValueException, ClassNotFoundException
{
if (value != null && clazz.isAssignableFrom(value.getClass()) == false)
throw new InvalidAttributeValueException(context + " has class " + value.getClass() + " loaded from " + value.getClass().getClassLoader() +
" that is not assignable to attribute class " + clazz + " loaded from " + clazz.getClassLoader());
}
}