Package com.ibm.websphere.scheduler
The scheduler adds a persistent, transactional timer service to J2EE applications.
See:
Description
Package com.ibm.websphere.scheduler Description
The scheduler adds a persistent, transactional timer service to J2EE applications. It allows
a server application to periodically invoke a session bean or send a JMS message using a flexible
pluggable calendar mechanism.
Required jars
Applications that use these APIs must have the scheduler-client.jar JAR in
the Java classpath. This is located in the lib directory of the WebSphere Application Server.
Scheduler
A scheduler allows an application to schedule a single or repeating task. This is done persistently and
transactionally using the
Scheduler interface.
Each task is guaranteed to run exactly once. The task can either call a stateless session
bean or the send a JMS message to a queue or topic.
The time at which the task runs can be specified using a java.util.Date or a
calendar interval. See the calendars section below for more information.
EJB Task
When a task calls a session bean using the
BeanTaskInfo interface,
the target session bean must use a specific home and remote interface
(TaskHandler and
TaskHandlerHome). These interfaces
cannot be extended and must be used as-is. Once the session bean is called, it can call any business logic
that it chooses. It is called inside a transaction provided by the scheduler. If it fails or rolls back then
it will be rolled back and will automatically be retried until successful or cancelled.
JMS Task
When a task sends a JMS message using the
MessageTaskInfo interface,
the body and headers can be provided along with the queue connection factory
or topic connection factory and queue/topic to use. This will be sent within the scheduler transaction.
Calendars
The scheduler allows applications to specify a time based interval for the tasks to run. The
scheduler provides a set of calendars in the SchedulerCalendars system application
that all applications can use. Additional calendars can be created and are
implemented as stateless session beans. Each bean must specify the
UserCalendar remote interface and
UserCalendarHome home interface. Once a
bean is created and deployed, applications can specify which calendar EJB
to use on a task by task basis. These calendar
EJBs must be made available to each server that could potentially run the task.
- Version:
- 1.1.0