| Timer.java |
/*
* JBoss, the OpenSource EJB server
*
* Distributable under LGPL license.
* See terms of license at gnu.org.
*/
package javax.management.timer;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Vector;
import javax.management.InstanceNotFoundException;
import javax.management.MBeanRegistration;
import javax.management.MBeanServer;
import javax.management.NotificationBroadcasterSupport;
import javax.management.ObjectName;
import org.jboss.mx.util.RunnableScheduler;
import org.jboss.mx.util.SchedulableRunnable;
import org.jboss.logging.Logger;
/**
* The timer service.
*
* @author <a href="mailto:Adrian.Brock@HappeningTimes.com">Adrian Brock</a>
* @version $Revision: 1.14 $
*/
public class Timer
extends NotificationBroadcasterSupport
implements TimerMBean, MBeanRegistration
{
// logging support
private static Logger log = Logger.getLogger(Timer.class);
// Constants -----------------------------------------------------
/**
* The number of milliseconds in one second.
*/
public static final long ONE_SECOND = 1000;
/**
* The number of milliseconds in one minute.
*/
public static final long ONE_MINUTE = ONE_SECOND * 60;
/**
* The number of milliseconds in one hour.
*/
public static final long ONE_HOUR = ONE_MINUTE * 60;
/**
* The number of milliseconds in one day.
*/
public static final long ONE_DAY = ONE_HOUR * 24;
/**
* The number of milliseconds in one week.
*/
public static final long ONE_WEEK = ONE_DAY * 7;
/**
* Don't send notifications at initial start up.
*/
private static final int SEND_NO = 0;
/**
* Send all past notifications at initial start up.
*/
private static final int SEND_START = 1;
/**
* Normal operation sending
*/
private static final int SEND_NORMAL = 2;
// Attributes ----------------------------------------------------
/**
* The next notification id.
*/
int nextId = 0;
/**
* The next notification sequence number.
*/
long sequenceNumber = 0;
/**
* The send past events attribute.
*/
boolean sendPastNotifications = false;
/**
* Whether the service is active.
*/
boolean active = false;
/**
* Our object name.
*/
ObjectName objectName;
/**
* The registered notifications.
*/
HashMap notifications = new HashMap();
/**
* The scheduler
*/
private RunnableScheduler scheduler = new RunnableScheduler();
// Static --------------------------------------------------------
// Constructors --------------------------------------------------
// Public --------------------------------------------------------
// TimerMBean implementation -------------------------------------
public Integer addNotification(String type, String message, Object userData,
Date date)
throws IllegalArgumentException
{
return addNotification(type, message, userData, date, 0);
}
public Integer addNotification(String type, String message, Object userData,
Date date, long period)
throws IllegalArgumentException
{
return addNotification(type, message, userData, date, period, 0);
}
public Integer addNotification(String type, String message,
Object userData, Date date, long period, long occurences)
throws IllegalArgumentException
{
// Generate the next id.
int newId = 0;
newId = ++nextId;
Integer id = new Integer(newId);
// Validate and create the registration.
RegisteredNotification rn =
new RegisteredNotification(id, type, message, userData, date, period,
occurences);
// Add the registration.
synchronized(notifications)
{
notifications.put(id, rn);
rn.setNextRun(rn.nextDate);
rn.setScheduler(scheduler);
}
return id;
}
public Vector getAllNotificationIDs()
{
synchronized(notifications)
{
return new Vector(notifications.keySet());
}
}
public Date getDate(Integer id)
{
// Make sure there is a registration
RegisteredNotification rn = (RegisteredNotification) notifications.get(id);
if (rn == null)
return null;
// Return a copy of the date.
return new Date(rn.startDate);
}
public int getNbNotifications()
{
return notifications.size();
}
public Long getNbOccurences(Integer id)
{
// Make sure there is a registration
RegisteredNotification rn = (RegisteredNotification) notifications.get(id);
if (rn == null)
return null;
// Return a copy of the occurences.
return new Long(rn.occurences);
}
/**
* Gets a copy of the flag indicating whether a peridic notification is executed at fixed-delay or at fixed-rate.
*
* @param id The timer notification identifier.
* @return A copy of the flag indicating whether a peridic notification is executed at fixed-delay or at fixed-rate.
*/
public Boolean getFixedRate(Integer id)
{
//[todo] implement getFixedRate
throw new RuntimeException("NYI");
}
public Vector getNotificationIDs(String type)
{
Vector result = new Vector();
// Loop through the notifications looking for the passed type.
synchronized (notifications)
{
Iterator iterator = notifications.values().iterator();
while (iterator.hasNext())
{
RegisteredNotification rn = (RegisteredNotification) iterator.next();
if (rn.type.equals(type))
result.add(rn.id);
}
}
return result;
}
public String getNotificationMessage(Integer id)
{
// Make sure there is a registration
RegisteredNotification rn = (RegisteredNotification) notifications.get(id);
if (rn == null)
return null;
// Return the message
return rn.message;
}
public String getNotificationType(Integer id)
{
// Make sure there is a registration
RegisteredNotification rn = (RegisteredNotification) notifications.get(id);
if (rn == null)
return null;
// Return the type.
return rn.type;
}
public Object getNotificationUserData(Integer id)
{
// Make sure there is a registration
RegisteredNotification rn = (RegisteredNotification) notifications.get(id);
if (rn == null)
return null;
// Return the user data.
return rn.userData;
}
public Long getPeriod(Integer id)
{
// Make sure there is a registration
RegisteredNotification rn = (RegisteredNotification) notifications.get(id);
if (rn == null)
return null;
// Return a copy of the period
return new Long(rn.period);
}
public boolean getSendPastNotifications()
{
return sendPastNotifications;
}
public boolean isActive()
{
return active;
}
public boolean isEmpty()
{
return notifications.isEmpty();
}
public void removeAllNotifications()
{
// Remove the notifications
synchronized(notifications)
{
Iterator iterator = notifications.values().iterator();
while (iterator.hasNext())
{
RegisteredNotification rn = (RegisteredNotification) iterator.next();
rn.setScheduler(null);
iterator.remove();
}
}
// The spec says to reset the identifiers, seems like a bad idea to me
synchronized (this)
{
nextId = 0;
}
}
public void removeNotification(Integer id)
throws InstanceNotFoundException
{
log.debug("removeNotification: " + objectName + ",id=" + id);
// Check if there is a notification.
synchronized(notifications)
{
RegisteredNotification rn = (RegisteredNotification) notifications.get(id);
if (rn == null)
throw new InstanceNotFoundException("No notification id : " +
id.toString());
// Remove the notification
rn.setScheduler(null);
notifications.remove(id);
}
}
public void removeNotifications(String type)
throws InstanceNotFoundException
{
boolean found = false;
log.debug("removeNotifications: " + objectName + ",type=" + type);
// Loop through the notifications removing the passed type.
synchronized(notifications)
{
Iterator iterator = notifications.values().iterator();
while (iterator.hasNext())
{
RegisteredNotification rn = (RegisteredNotification) iterator.next();
if (rn.type.equals(type))
{
rn.setScheduler(null);
iterator.remove();
found = true;
}
}
}
// The spec says to through an exception when nothing removed.
if (found == false)
throw new InstanceNotFoundException("Nothing registered for type: " +
type);
}
public void setSendPastNotifications(boolean value)
{
log.debug("setSendPastNotifications: " + objectName + ",value=" + value);
sendPastNotifications = value;
}
public synchronized void start()
{
// Ignore if already active
if (active == true)
return;
active = true;
log.debug("start: " + objectName + " at " + new Date());
// Perform the initial sends, for past notifications send missed events
// otherwise ignore them
synchronized (notifications)
{
Iterator iterator = notifications.values().iterator();
while (iterator.hasNext())
{
RegisteredNotification rn = (RegisteredNotification) iterator.next();
if (sendPastNotifications)
rn.sendType = SEND_START;
else
rn.sendType = SEND_NO;
sendNotifications(rn);
rn.sendType = SEND_NORMAL;
}
}
// Start 'em up
scheduler.start();
}
public synchronized void stop()
{
// Ignore if not active
if (active == false)
return;
log.debug("stop: " + objectName + ",now=" + new Date());
// Stop the threads
active = false;
scheduler.stop();
}
/**
* Creates a new timer notification with the specified type, message and userData and inserts it into the list of notifications with a given date, period and number of occurences.
* <p/>
* If the timer notification to be inserted has a date that is before the current date, the method behaves as if the specified date were the current date.
* For once-off notifications, the notification is delivered immediately.
* For periodic notifications, the first notification is delivered immediately and the subsequent ones are spaced as specified by the period parameter.
* <p/>
* Note that once the timer notification has been added into the list of notifications, its associated date, period and number of occurences cannot be updated.
* <p/>
* In the case of a periodic notification, the value of parameter fixedRate is used to specify the execution scheme, as specified in Timer.
*
* @param type The timer notification type.
* @param message The timer notification detailed message.
* @param userData The timer notification user data object.
* @param date The date when the notification occurs.
* @param period The period of the timer notification (in milliseconds).
* @param nbOccurences The total number the timer notification will be emitted.
* @param fixedRate If true and if the notification is periodic, the notification is scheduled with a fixed-rate execution scheme. If false and if the notification is periodic, the notification is scheduled with a fixed-delay execution scheme. Ignored if the notification is not periodic.
* @return The identifier of the new created timer notification.
* @throws IllegalArgumentException The period or the number of occurences is negative
*/
public Integer addNotification(String type, String message, Object userData, Date date, long period, long nbOccurences, boolean fixedRate) throws IllegalArgumentException
{
// [todo] implement addNotification
throw new RuntimeException("NYI");
}
// MBeanRegistrationImplementation overrides ---------------------
public ObjectName preRegister(MBeanServer server, ObjectName objectName)
throws Exception
{
// Save the object name
this.objectName = objectName;
// Use the passed object name.
return objectName;
}
public void postRegister(Boolean registrationDone)
{
}
public void preDeregister()
throws Exception
{
// Stop the timer before deregistration.
stop();
}
public void postDeregister()
{
}
// Package protected ---------------------------------------------
// Protected -----------------------------------------------------
// Private -------------------------------------------------------
/**
* Send any outstanding notifications.
*
* @param rn the registered notification to send.
*/
private void sendNotifications(RegisteredNotification rn)
{
// Keep going until we have done all outstanding notifications.
// The loop ends when not active, or there are no outstanding
// notifications.
// REVIEW: In practice for normal operation it never loops. We
// ignore sends that we have missed. This avoids problems where
// the notification takes longer than the period. Correct???
while (isActive() && rn.nextDate != 0
&& rn.nextDate <= System.currentTimeMillis())
{
// Do we actually send it?
// Yes, unless start and not sending past notifications.
if (rn.sendType != SEND_NO)
{
long seq = 0;
synchronized (this)
{
seq = ++sequenceNumber;
}
log.debug("sendNotification: " + rn);
TimerNotification tn = new TimerNotification(rn.type, objectName,
seq, rn.nextDate, rn.message, rn.id);
tn.setUserData(rn.userData);
sendNotification(tn);
}
// Calculate the next date.
// Except for when we are sending past notifications at start up,
// it cannot be in the future.
do
{
// If no next run, remove it sets the next date to zero.
if (rn.calcNextDate() == false)
{
synchronized (notifications)
{
log.debug("remove: " + rn);
notifications.remove(rn.id);
}
}
}
while (isActive() && rn.sendType != SEND_START && rn.nextDate != 0
&& rn.occurences == 0 && rn.nextDate < System.currentTimeMillis());
}
if (rn.nextDate != 0)
rn.setNextRun(rn.nextDate);
}
// Inner classes -------------------------------------------------
/**
* A registered notification. These run as separate threads.
*/
private class RegisteredNotification
extends SchedulableRunnable
{
// Attributes ----------------------------------------------------
/**
* The notification id.
*/
public Integer id;
/**
* The notification type.
*/
public String type;
/**
* The message.
*/
public String message;
/**
* The user data.
*/
public Object userData;
/**
* The start date.
*/
public long startDate;
/**
* The period.
*/
public long period;
/**
* The maximum number of occurences.
*/
public long occurences;
/**
* The send type, no send, past notifications or normal
*/
public int sendType = SEND_NORMAL;
/**
* The next run date
*/
public long nextDate = 0;
// Constructors --------------------------------------------------
/**
* The default constructor.
*
* @param id the notification id.
* @param type the notification type.
* @param message the notification's message string.
* @param userData the notification's user data.
* @param startDate the date/time the notification will occur.
* @param period the repeat period in milli-seconds. Passing zero means
* no repeat.
* @param occurences the maximum number of repeats. When the period is not
* zero and this parameter is zero, it will repeat indefinitely.
* @exception IllegalArgumentException when the date is before the current
* date, the period is negative or the number of repeats is
* negative.
*/
public RegisteredNotification(Integer id, String type, String message, Object userData, Date startDate, long period, long occurences)
throws IllegalArgumentException
{
// Basic validation
if (startDate == null)
throw new IllegalArgumentException("Null Date");
if (period < 0)
throw new IllegalArgumentException("Negative Period");
if (occurences < 0)
throw new IllegalArgumentException("Negative Occurences");
this.startDate = startDate.getTime();
if (startDate.getTime() < System.currentTimeMillis())
{
log.warn("startDate [" + startDate + "] in the past, set to now");
this.startDate = System.currentTimeMillis();
}
// Remember the values
this.id = id;
this.type = type;
this.message = message;
this.userData = userData;
this.period = period;
this.occurences = occurences;
this.nextDate = this.startDate;
String msgStr = "new " + this.toString();
log.debug(msgStr);
}
// Public --------------------------------------------------------
/**
* Calculate the next notification date. Add on the period until
* the number of occurences is exhausted.
*
* @return false when there are no more occurences, true otherwise.
*/
boolean calcNextDate()
{
// No period, we've finished
if (period == 0)
{
nextDate = 0;
return false;
}
// Limited number of repeats have we finished?
if (occurences != 0 && --occurences == 0)
{
nextDate = 0;
return false;
}
// Calculate the next occurence
nextDate += period;
return true;
}
// SchedulableRunnable overrides ---------------------------------
/**
* Send the notifications.
*/
public void doRun()
{
// Send any notifications
sendNotifications(this);
}
public String toString()
{
return " RegisteredNotification: [timer=" + objectName + ",id=" + id + ",startDate=" + new Date(startDate) +
",periode=" + period + ",occurences=" + occurences + ",nextDate=" + new Date(nextDate) + "]";
}
}
}
| Timer.java |