EJB's Timer

EJB Timer

• Either: Annotation @Schedule or method before declaring @timeout
• Either: Define Timeout-method in the deployment description

• If you are using @schedule, the timer can support multiple in one EJB, such as:

@Schedule (second= "*/2", minute= "*", hour= "*", persistent=false,info= "Timer1")
public void DoWork () {
System.out.println ("Hi from the EJB timer example!");
}


@Schedule (second= "*/1", minute= "*", hour= "*", persistent=false,info= "Timer2")
public void DoWork2 () {
System.out.println ("Hi ....") 2nd timer! ");
}
Each of the above starts with 2 timer, one executes every 2 seconds, and one executes every 1 seconds. Container does concurrent access control at execution time. That means the callback method can only execute one method at a time.

• If you are using @timeout, which is programmatic timers, the callback method has only one.

All timers created via one of the Timerservice timer creation methods for a particular component use a single timeout call Back method. --from EJB Spec 3.1 Chapter 18
If the previous call is not completed and the next timer comes up, then the timer will wait (that is, lock). As follows:

09:20:59,045 ERROR [org.jboss.as.ejb3] (EJB default-2) jbas014122:error during retrying timeout for timer: [id=c2a31520 -2c55-4b01-b362-d8dfdb73a2d0 Timedobjectid=jboss-ejb-timer.jboss-ejb-timer.timeoutexample Auto-timer?:false persistent?:false [email protected]86ae8 initialexpiration=tue Mar 09:20:48 CST intervalduration (in milli sec) =0 N Extexpiration=null TIMERSTATE=RETRY_TIMEOUT:JAVAX.EJB.CONCURRENTACCESSTIMEOUTEXCEPTION:JBAS014373:EJB 3.1 PFD2 4.8.5.5.1 concurrent access timeout on [email protected]-could not obtain lock within 5000MILLISECONDS
At Org.jboss.as.ejb3.concurrency.ContainerManagedConcurrencyInterceptor.processInvocation ( CONTAINERMANAGEDCONCURRENCYINTERCEPTOR.JAVA:100) [jboss-as-ejb3-7.3.0.final-redhat-14.jar:7.3.0.final-redhat-14 ]

After the timer waits 5 seconds, it will retry again (JBoss implementation). If it is a timeout, it will be discarded.

Timerservice's Createsingleactiontimer () and Createintervaltimer ()

• Createsingleactiontimer

Trigger only once, if the trigger is not the lock, timeout, as described above, try again, if not, give up directly.

• Createintervaltimer

Periodic trigger, point trigger found the last not finished, then skip directly, give up, and then wait for the next, the following code

@Timeout
public void Scheduler (timer timer) {
System.out.println ("EJB timer:info=" + timer.getinfo () + "" + Thread.CurrentThread (). GetName ());

Added by Xilun
try {
Thread.Sleep (1000*30);
} catch (Interruptedexception e) {
E.printstacktrace ();
}
}


//
@PostConstruct
public void Initialize (Invocationcontext ctx) {
//...
Timerservice.createintervaltimer (10*1000, New Timerconfig ("Single Timer #2", false));
//....
}

The output log is as follows:
10:21:47,864 INFO [stdout] (EJB default-7) EJB timer:info=single Timer #2 EJB default-7

10:21:57,864 WARN [org.jboss.as.ejb3] (EJB default-9) jbas014143:a Previous execution of timer [jboss-ejb-timer.jboss- Ejb-timer. Timeoutexample 8ba38f5a-0da7-4993-8b0b-e69854f61ee4] is still in progress, skipping this overlapping scheduled execution At:tue Mar 10:21:57 CST 2016
10:22:07,864 WARN [org.jboss.as.ejb3] (EJB default-6) jbas014143:a Previous execution of timer [jboss-ejb-timer.jboss- Ejb-timer. Timeoutexample 8ba38f5a-0da7-4993-8b0b-e69854f61ee4] is still in progress, skipping this overlapping scheduled execution At:tue Mar 10:22:07 CST 2016
10:22:17,864 WARN [org.jboss.as.ejb3] (EJB default-8) jbas014143:a Previous execution of timer [jboss-ejb-timer.jboss- Ejb-timer. Timeoutexample 8ba38f5a-0da7-4993-8b0b-e69854f61ee4] is still in progress, skipping this overlapping scheduled execution At:tue Mar 10:22:17 CST 2016
10:22:27,865 INFO [stdout] (EJB default-3) EJB timer:info=single Timer #2 EJB default-3

10:22:37,864 WARN [org.jboss.as.ejb3] (EJB default-10) jbas014143:a Previous execution of timer [Jboss-ejb-timer.jboss -ejb-timer. Timeoutexample 8ba38f5a-0da7-4993-8b0b-e69854f61ee4] is still in progress, skipping this overlapping scheduled execution At:tue Mar 10:22:37 CST 2016
10:22:47,864 WARN [org.jboss.as.ejb3] (EJB default-2) jbas014143:a Previous execution of timer [jboss-ejb-timer.jboss- Ejb-timer. Timeoutexample 8ba38f5a-0da7-4993-8b0b-e69854f61ee4] is still in progress, skipping this overlapping scheduled execution At:tue Mar 10:22:47 CST 2016
10:22:57,864 WARN [org.jboss.as.ejb3] (EJB default-1) jbas014143:a Previous execution of timer [jboss-ejb-timer.jboss- Ejb-timer. Timeoutexample 8ba38f5a-0da7-4993-8b0b-e69854f61ee4] is still in progress, skipping this overlapping scheduled execution At:tue Mar 10:22:57 CST 2016

There is an example of a timer in Jboss QuickStart.

EJB's Timer