actualtimer.java

High performance DB query

/*
 * @(#)$Id: ActualTimer.java,v 1.4 2005/07/09 20:11:14 huebsch Exp $
 *
 * Copyright (c) 2001-2004 Regents of the University of California.
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached BERKELEY-LICENSE
 * file. If you do not find these files, copies can be found by writing to:
 * Computer Science Division, Database Group, Universite of California,
 * 617 Soda Hall #1776, Berkeley, CA 94720-1776. Attention: Berkeley License
 *
 * Copyright (c) 2003-2004 Intel Corporation. All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE file.
 * If you do not find these files, copies can be found by writing to:
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300,
 * Berkeley, CA, 94704.  Attention:  Intel License Inquiry.
 */


package runtime.services.timer;

import execution.EndExecution;
import java.text.DateFormat;
import java.util.Date;
import java.util.TreeMap;
import services.timer.Timer;
import services.timer.TimerClient;

/**
 * Class ActualTimer
 *
 */
public class ActualTimer implements Timer {

    private long timeOffset;
    private Object syncObject;
    private TreeMap events;
    private ActualTimerThread runner;

    /**
     * Constructor ActualTimer
     *
     * @param defaultSleepTime
     * @param beginTime
     * @param ignoreBeginTime
     * @param syncObject
     */
    public ActualTimer(long defaultSleepTime, String beginTime,
                       boolean ignoreBeginTime, Object syncObject) {
        if (ignoreBeginTime) {
            this.timeOffset = System.currentTimeMillis();
        } else {
            try {
                DateFormat beginDate =
                    DateFormat.getDateTimeInstance(DateFormat.SHORT,
                                                   DateFormat.SHORT);

                beginDate.setLenient(true);

                this.timeOffset =
                    ((Date) beginDate.parseObject(beginTime)).getTime();
            } catch (Exception exception) {
                throw new RuntimeException("TIMER: Unable to parse begin time: "
                                           + beginTime + ", "
                                           + exception.getMessage());
            }
        }

        this.syncObject = syncObject;
        events = new TreeMap();
        runner = new ActualTimerThread(events, this, defaultSleepTime);

        runner.start();
    }

    /**
     * Method schedule
     *
     * @param relativeTime
     * @param data
     * @param client
     */
    public void schedule(double relativeTime, Object data, TimerClient client) {
        ActualTimerEvent firstEvent = null;
        double executionTime = relativeTime + getCurrentTime();
        ActualTimerEvent event = ActualTimerEvent.allocate(executionTime, data,
                                     client);

        // Synchronize actions that read/insert the shared treemap
        synchronized (events) {
            if (events.size() > 0) {
                firstEvent = ((ActualTimerEvent) events.firstKey());
            }

            events.put(event, event);
        }

        // Check if this event is earlier than all other events, if so wake thread so it can reset timers
        if ((firstEvent == null)
                || (firstEvent.getExecutionTime() > executionTime)) {
            runner.interrupt();
        }
    }

    /**
     * Method scheduleMS
     *
     * @param relativeTimeMS
     * @param data
     * @param client
     */
    public void scheduleMS(long relativeTimeMS, Object data,
                           TimerClient client) {
        schedule(((double) relativeTimeMS) / 1000D, data, client);
    }

    /**
     * Method getCurrentTime
     * @return
     */
    public double getCurrentTime() {
        return (((double) (System.currentTimeMillis() - timeOffset))
                / ((double) 1000));
    }

    /**
     * Method getCurrentTimeMS
     * @return
     */
    public long getCurrentTimeMS() {
        return System.currentTimeMillis() - timeOffset;
    }

    /**
     * Method runEvent
     *
     * @param event
     */
    protected void runEvent(ActualTimerEvent event) {

        // run the event
        TimerClient client = event.getClient();

        synchronized (syncObject) {
            try {
                client.handleClock(event.getData());
            } catch (Exception exception) {
                EndExecution.masterSync = exception;

                runner.end();
            }
        }

        ActualTimerEvent.free(event);
    }
}