Mercurial > hg > release > thermostat-0.6
view agent/core/src/main/java/com/redhat/thermostat/backend/VmListenerBackend.java @ 989:cf7a445c359b
Refactoring and cleanup of Backend
Reviewed-by: omajid
Review-thread: http://icedtea.classpath.org/pipermail/thermostat/2013-February/005705.html
author | Jon VanAlten <jon.vanalten@redhat.com> |
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date | Fri, 15 Feb 2013 15:16:47 -0500 |
parents | f6bc84590701 |
children |
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/* * Copyright 2012, 2013 Red Hat, Inc. * * This file is part of Thermostat. * * Thermostat is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published * by the Free Software Foundation; either version 2, or (at your * option) any later version. * * Thermostat 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 for more details. * * You should have received a copy of the GNU General Public License * along with Thermostat; see the file COPYING. If not see * <http://www.gnu.org/licenses/>. * * Linking this code with other modules is making a combined work * based on this code. Thus, the terms and conditions of the GNU * General Public License cover the whole combination. * * As a special exception, the copyright holders of this code give * you permission to link this code with independent modules to * produce an executable, regardless of the license terms of these * independent modules, and to copy and distribute the resulting * executable under terms of your choice, provided that you also * meet, for each linked independent module, the terms and conditions * of the license of that module. An independent module is a module * which is not derived from or based on this code. If you modify * this code, you may extend this exception to your version of the * library, but you are not obligated to do so. If you do not wish * to do so, delete this exception statement from your version. */ package com.redhat.thermostat.backend; import java.net.URISyntaxException; import java.util.HashMap; import java.util.Map; import java.util.logging.Level; import java.util.logging.Logger; import sun.jvmstat.monitor.HostIdentifier; import sun.jvmstat.monitor.MonitorException; import sun.jvmstat.monitor.MonitoredHost; import sun.jvmstat.monitor.MonitoredVm; import sun.jvmstat.monitor.VmIdentifier; import sun.jvmstat.monitor.event.VmListener; import com.redhat.thermostat.agent.VmStatusListener; import com.redhat.thermostat.agent.VmStatusListenerRegistrar; import com.redhat.thermostat.common.Pair; import com.redhat.thermostat.common.utils.LoggingUtils; /** * This class is a convenient subclass of {@link Backend} (via {@link BaseBackend}) for those * that need to attach {@link VmListener} in response to starting and stopping of JVMs on a * host. * * @see VmStatusListener * @see Backend * @see BaseBackend */ public abstract class VmListenerBackend extends BaseBackend implements VmStatusListener { private static final Logger logger = LoggingUtils.getLogger(VmListenerBackend.class); private MonitoredHost host; private Map<Integer, Pair<MonitoredVm, ? extends VmListener>> pidToData = new HashMap<>(); private final VmStatusListenerRegistrar registrar; private boolean started; public VmListenerBackend(String backendName, String description, String vendor, String version, VmStatusListenerRegistrar registrar) { this(backendName, description, vendor, version, false, registrar); } public VmListenerBackend(String backendName, String description, String vendor, String version, boolean observeNewJvm, VmStatusListenerRegistrar registrar) { super(backendName, description, vendor, version, observeNewJvm); this.registrar = registrar; try { HostIdentifier hostId = new HostIdentifier((String) null); host = MonitoredHost.getMonitoredHost(hostId); } catch (MonitorException me) { logger.log(Level.WARNING, "Problems with connecting jvmstat to local machine", me); } catch (URISyntaxException use) { logger.log(Level.WARNING, "Failed to create host identifier", use); } } /** * {@inheritDoc} * * <p> * Registers a VmListener to begin receiving VM lifecycle events. * Subclasses should call <code>super.activate()</code> when overriding this method. * </p> */ @Override public boolean activate() { if (!started && host != null) { registrar.register(this); started = true; } return started; } /** * {@inheritDoc} * * <p> * Unregisters the VmListener to stop receiving VM lifecycle events. * Subclasses should call <code>super.deactivate()</code> when overriding this method. * </p> */ @Override public boolean deactivate() { if (started) { registrar.unregister(this); removeVmListeners(); started = false; } return !started; } @Override public boolean isActive() { return started; } public void vmStatusChanged(Status newStatus, int pid) { switch (newStatus) { case VM_STARTED: /* fall-through */ case VM_ACTIVE: handleNewVm(pid); break; case VM_STOPPED: handleStoppedVm(pid); break; default: break; } } private void handleNewVm(int pid) { if (getObserveNewJvm()) { try { MonitoredVm vm = host.getMonitoredVm(host.getHostIdentifier().resolve(new VmIdentifier(String.valueOf(pid)))); VmListener listener = createVmListener(pid); vm.addVmListener(listener); pidToData.put(pid, new Pair<>(vm, listener)); logger.finer("Attached VmListener for VM: " + pid); } catch (MonitorException | URISyntaxException e) { logger.log(Level.WARNING, "unable to attach to vm " + pid, e); } } else { logger.log(Level.FINE, "skipping new vm " + pid); } } private void handleStoppedVm(int pid) { Pair<MonitoredVm, ? extends VmListener> data = pidToData.remove(pid); // we were not monitoring pid at all, so nothing to do if (data == null) { return; } MonitoredVm vm = data.getFirst(); VmListener listener = data.getSecond(); try { vm.removeVmListener(listener); } catch (MonitorException e) { logger.log(Level.WARNING, "can't remove vm listener", e); } vm.detach(); } private void removeVmListeners() { for (Pair<MonitoredVm, ? extends VmListener> data : pidToData.values()) { MonitoredVm vm = data.getFirst(); VmListener listener = data.getSecond(); try { vm.removeVmListener(listener); } catch (MonitorException e) { logger.log(Level.WARNING, "can't remove vm listener", e); } } } /** * Creates a new {@link VmListener} for the virtual machine * specified by the pid. This method is called when a new * JVM is started or for JVMs already active when this Backend * was activated. * @param pid the process ID of the JVM * @return a new VmListener for the VM specified by pid */ protected abstract VmListener createVmListener(int pid); /* * For testing purposes only. */ void setHost(MonitoredHost host) { this.host = host; } /* * For testing purposes only. */ Map<Integer, Pair<MonitoredVm, ? extends VmListener>> getPidToDataMap() { return pidToData; } }