Java Reference
In-Depth Information
Listing 7.4.
FlyerBean
implementation
The
FlyerBean
in this listing is responsible for scheduling the flyer for delivery and also
sending the email when the timer expires. The
TimerService
is injected via an annota-
tion . The method
getScheduledFlyers
has been implemented to drive a web page
enabling someone in marketing to see which flyers have been scheduled for delivery .
The
scheduleFlyer
method is responsible for scheduling the flyer. The user interface
constructs an instance of
ScheduleExpression
that will ultimately be passed off to
the
TimerService
. A
TimerConfig
instance is created to encapsulate the flyer and
also specify that this timer should survive server restarts . A
Timer
is created inside the
TimerService
using the scheduling from the
ScheduleExpression
and the con-
figuration from the
TimerConfig
. Once a
Timer
is created, information about it
may be retrieved, such as the next time the timer will time out
. The
send
method is
annotated with
@TimeOut
to mark it as the method responsible for executing the task
with the timer completes.
This example is straightforward. The
TimerService
creates timers that are associated
with the current bean. The method to be invoked when the timer expires can either
