Interface IProgressListener
- All Known Implementing Classes:
ConsoleProgressListener
,ProgressMonitorWrapper
,SilentProgressListener
,SimpleMonitor.Listener
,VoidProgressListener
All activity is broken down into a linear sequence of tasks against which
progress is reported. When a task begins, a beginTask(String, int)
notification is reported,
followed by any number and mixture of progress reports (worked()
) and subtask notifications (subTask(String)
). When the task is
eventually completed, a done()
notification is reported. After
the done()
notification, the progress monitor cannot be reused;
i.e.,
beginTask(String, int)
cannot be called again after the call to
done()
.
A request to cancel an operation can be signaled using the
setCanceled
method. Operations taking a progress monitor are
expected to poll the monitor (using isCanceled
) periodically and
abort at their earliest convenience. Operation can however choose to ignore
cancellation requests.
Since notification is synchronous with the activity itself, the listener should provide a fast and robust implementation. If the handling of notifications would involve blocking operations, or operations which might throw uncaught exceptions, the notifications should be queued, and the actual processing deferred (or perhaps delegated to a separate thread).
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Nested Class Summary
Modifier and TypeInterfaceDescriptionstatic class
Helper exception class which can be used to exit an operation via an exception if the operation itself has been canceled.static enum
Defines the severities possible for a user message. -
Field Summary
Modifier and TypeFieldDescriptionstatic final int
Constant which may be used to indicate that the total amount of work units is not known. -
Method Summary
Modifier and TypeMethodDescriptionvoid
Notifies that the main task is beginning.void
done()
Notifies that the work is done; that is, either the main task is completed or the user canceled it.boolean
Returns whether cancelation of current operation has been requested.void
sendUserMessage
(IProgressListener.Severity severity, String message, Throwable exception) Sends a message to the user.void
setCanceled
(boolean value) Sets the cancel state to the given value.void
Notifies that a subtask of the main task is beginning.void
worked
(int work) Notifies that a given number of work unit of the main task has been completed.
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Field Details
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UNKNOWN_TOTAL_WORK
static final int UNKNOWN_TOTAL_WORKConstant which may be used to indicate that the total amount of work units is not known.- See Also:
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Method Details
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beginTask
Notifies that the main task is beginning. This must only be called once on a given progress monitor instance.- Parameters:
name
- the name (or description) of the main tasktotalWork
- the total number of work units into which the main task is been subdivided. If the value isUNKNOWN
the implementation is free to indicate progress in a way which doesn't require the total number of work units in advance.
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done
void done()Notifies that the work is done; that is, either the main task is completed or the user canceled it. This method may be called more than once (implementations should be prepared to handle this case). -
isCanceled
boolean isCanceled()Returns whether cancelation of current operation has been requested. Long-running operations should poll to see if cancelation has been requested.- Returns:
true
if cancellation has been requested, andfalse
otherwise- See Also:
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setCanceled
void setCanceled(boolean value) Sets the cancel state to the given value.- Parameters:
value
-true
indicates that cancelation has been requested (but not necessarily acknowledged);false
clears this flag- See Also:
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subTask
Notifies that a subtask of the main task is beginning. Subtasks are optional; the main task might not have subtasks.- Parameters:
name
- the name (or description) of the subtask
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worked
void worked(int work) Notifies that a given number of work unit of the main task has been completed. Note that this amount represents an installment, as opposed to a cumulative amount of work done to date.- Parameters:
work
- the number of work units just completed
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sendUserMessage
Sends a message to the user.- Parameters:
severity
- Severity as defined inIProgressListener.Severity
message
- The message localized to the current locale.exception
- The relevant low-level exception, ornull
if none.
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