/*
* Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.jvmstat.perfdata.monitor.protocol.local;
import java.util.*;
import java.lang.reflect.*;
import java.io.*;
import sun.jvmstat.monitor.*;
import sun.jvmstat.monitor.event.*;
import sun.jvmstat.perfdata.monitor.*;
/**
* Concrete implementation of the AbstractMonitoredVm class for the
* <em>local:</em> protocol for the HotSpot PerfData monitoring implementation.
* <p>
* This class provides the ability to attach to the instrumentation buffer
* of a live target Java Virtual Machine through a HotSpot specific attach
* mechanism.
*
* @author Brian Doherty
* @since 1.5
*/
public class LocalMonitoredVm extends AbstractMonitoredVm {
/**
* List of registered listeners.
*/
private ArrayList<VmListener> listeners;
/**
* Task performing listener notification.
*/
private NotifierTask task;
/**
* Create a LocalMonitoredVm instance.
*
* @param vmid the vm identifier specifying the target JVM
* @param interval the sampling interval
*/
public LocalMonitoredVm(VmIdentifier vmid, int interval)
throws MonitorException {
super(vmid, interval);
this.pdb = new PerfDataBuffer(vmid);
listeners = new ArrayList<VmListener>();
}
/**
* {@inheritDoc}.
*/
public void detach() {
if (interval > 0) {
/*
* if the notifier task is running, stop it, otherwise it can
* access non-existent memory once we've detached from the
* underlying buffer.
*/
if (task != null) {
task.cancel();
task = null;
}
}
super.detach();
}
/**
* {@inheritDoc}.
*/
public void addVmListener(VmListener l) {
synchronized(listeners) {
listeners.add(l);
if (task == null) {
task = new NotifierTask();
LocalEventTimer timer = LocalEventTimer.getInstance();
timer.schedule(task, interval, interval);
}
}
}
/**
* {@inheritDoc}.
*/
public void removeVmListener(VmListener l) {
synchronized(listeners) {
listeners.remove(l);
if (listeners.isEmpty() && task != null) {
task.cancel();
task = null;
}
}
}
/**
* {@inheritDoc}.
*/
public void setInterval(int newInterval) {
synchronized(listeners) {
if (newInterval == interval) {
return;
}
int oldInterval = interval;
super.setInterval(interval);
if (task != null) {
task.cancel();
NotifierTask oldTask = task;
task = new NotifierTask();
LocalEventTimer timer = LocalEventTimer.getInstance();
CountedTimerTaskUtils.reschedule(timer, oldTask, task,
oldInterval, newInterval);
}
}
}
/**
* Fire MonitoredVmStructureChanged events.
*
* @param inserted List of Monitor objects inserted.
* @param removed List of Monitor objects removed.
*/
void fireMonitorStatusChangedEvents(List inserted, List removed) {
MonitorStatusChangeEvent ev = null;
ArrayList registered = null;
synchronized (listeners) {
registered = (ArrayList)listeners.clone();
}
for (Iterator i = registered.iterator(); i.hasNext(); /* empty */) {
VmListener l = (VmListener)i.next();
// lazily create the event object;
if (ev == null) {
ev = new MonitorStatusChangeEvent(this, inserted, removed);
}
l.monitorStatusChanged(ev);
}
}
/**
* Fire MonitoredUpdated events.
*/
void fireMonitorsUpdatedEvents() {
VmEvent ev = null;
ArrayList<VmListener> registered = null;
synchronized (listeners) {
registered = cast(listeners.clone());
}
for (VmListener l : registered) {
// lazily create the event object;
if (ev == null) {
ev = new VmEvent(this);
}
l.monitorsUpdated(ev);
}
}
/**
* Class to notify listeners of Monitor related events for
* the target JVM.
*/
private class NotifierTask extends CountedTimerTask {
public void run() {
super.run();
try {
MonitorStatus status = getMonitorStatus();
List inserted = status.getInserted();
List removed = status.getRemoved();
if (!inserted.isEmpty() || !removed.isEmpty()) {
fireMonitorStatusChangedEvents(inserted, removed);
}
fireMonitorsUpdatedEvents();
} catch (MonitorException e) {
// XXX: use logging api
System.err.println("Exception updating monitors for "
+ getVmIdentifier());
e.printStackTrace();
}
}
}
// Suppress unchecked cast warning msg.
@SuppressWarnings("unchecked")
static <T> T cast(Object x) {
return (T) x;
}
}