WorkManager which provides a facility
to submit Work instances for execution. This frees the user
from having to create Java threads directly to do work. Further, this
allows efficient pooling of thread resources and more control over thread
usage.
The various stages in Work processing are:
Work instance is being submitted for
execution. The Work instance could either be accepted or
rejected with a WorkRejectedException set to an appropriate
error code. Work instance has been
accepted. The accepted Work instance could either start
execution or could be rejected again with a
WorkRejectedException set to an appropriate error code.
There is no guarantee on when the execution would start unless a start
timeout duration is specified. When a start timeout is specified, the
Work execution must be started within the specified
duration (not a real-time guarantee), failing which a
WorkRejectedException set to an error code
(WorkRejected.TIMED_OUT) is thrown. Work instance has been rejected.
The Work instance could be rejected during Work
submittal or after the Work instance has been accepted
(but before Work instance starts execution). The rejection could be due
to internal factors or start timeout expiration. A
WorkRejectedException with an appropriate error code
(indicates the reason) is thrown in both cases. Work
instance has started. This means that a thread
has been allocated for its execution. But this
does not guarantee that the allocated thread has been scheduled to run
on a CPU resource. Once execution is started, the allocated thread
sets up an appropriate execution context (transaction , security, etc)
and calls Work.run(). Note, any exception thrown during execution context
setup or Work.run() leads to completion of processing. Work has been
completed. The execution could complete with or without an exception.
The WorkManager catches any exception thrown during
Work processing (which includes execution context setup),
and wraps it with a WorkCompletedException. | Field Summary | |
|---|---|
| static long |
A constant to indicate timeout duration. |
| static long |
A constant to indicate timeout duration. |
| static long |
A constant to indicate an unknown start delay duration or other unknown values. |
| Method Summary | |
|---|---|
| void |
Accepts a Work instance for processing.
|
| void |
Accepts a Work instance for processing.
|
| void |
Accepts a Work instance for processing.
|
| void |
Accepts a Work instance for processing.
|
| long |
Accepts a Work instance for processing.
|
| long |
Accepts a Work instance for processing.
|
public static
long
IMMEDIATE
public static
long
INDEFINITE
public static
long
UNKNOWN
Work instance for processing. This call
blocks until the Work instance completes execution.
There is no guarantee on when the accepted Work
instance would start execution ie., there is no time constraint
to start execution. public
void
doWork
(
Work
work,
long
startTimeout,
ExecutionContext
execContext,
WorkListener
workListener
)
Work instance for processing. This call
blocks until the Work instance completes execution. Work instance for processing. This call
does not block and returns immediately once a Work
instance has been accepted for processing. There is no guarantee
on when the submitted Work instance would start
execution ie., there is no time constraint to start execution. public
void
scheduleWork
(
Work
work,
long
startTimeout,
ExecutionContext
execContext,
WorkListener
workListener
)
Work instance for processing. This call
does not block and returns immediately once a Work
instance has been accepted for processing. Work instance for processing. This call
blocks until the Work instance starts execution
but not until its completion. There is no guarantee on when
the accepted Work instance would start
execution ie., there is no time constraint to start execution. public
long
startWork
(
Work
work,
long
startTimeout,
ExecutionContext
execContext,
WorkListener
workListener
)
Work instance for processing. This call
blocks until the Work instance starts execution
but not until its completion. There is no guarantee on when
the accepted Work instance would start
execution ie., there is no time constraint to start execution. 