view agent/core/src/main/java/com/redhat/thermostat/backend/VmUpdateListener.java @ 1032:b269be10beb4

Wrap sun.jvmstat class usage Omair had pointed out that the VmListenerBackend exposes sun.jvmstat classes as API. These classes are subject to change and are not part of the Java specification. This commit resolves this issue by wrapping Thermostat's usage of these classes in a new set of API classes. A new VmUpdateListener is used in place of sun.jvmstat.monitor.VmListener. A new internal VmListenerWrapper class maps this class to the underlying VmListener. Performance counters retrieved from s.j.m.MonitoredVm can now be accessed through a new type-safe VmUpdate interface. Finally VmMonitor extracts some of the logic out of VmListenerBackend. With this commit, none of our plugins use any sun.jvmstat classes directly anymore. Reviewed-by: omajid Review-thread: http://icedtea.classpath.org/pipermail/thermostat/2013-March/006072.html
author Elliott Baron <ebaron@redhat.com>
date Fri, 15 Mar 2013 14:01:22 -0400
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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;

/**
 * A listener that can be registered to receive updates for a
 * JVM's performance counters.
 * @see VmListenerBackend#createVmListener(int)
 */
public interface VmUpdateListener {
    
    /**
     * This method is called when the performance counters
     * are updated for the JVM this listener is attached to.
     * @param update - object to query performance counter values
     */
    public void countersUpdated(VmUpdate update);

}