Library: Foundation
Package: Tasks
Header: Poco/Task.h
A Task is a subclass of Runnable that has a name and supports progress reporting and cancellation.
A TaskManager object can be used to take care of the lifecycle of a Task.
Direct Base Classes: Runnable, RefCountedObject
All Base Classes: RefCountedObject, Runnable
Member Functions: cancel, getOwner, isCancelled, name, postNotification, progress, reset, run, runTask, setOwner, setProgress, setState, sleep, state
Inherited Functions: duplicate, referenceCount, release, run
Task(
const std::string & name
);
Creates the Task.
virtual ~Task();
Destroys the Task.
virtual void cancel();
Requests the task to cancel itself. For cancellation to work, the task's runTask() method must periodically call isCancelled() and react accordingly.
Can be overridden to implement custom behavior, but the base class implementation of cancel() should be called to ensure proper behavior.
bool isCancelled() const;
Returns true if cancellation of the task has been requested.
A Task's runTask() method should periodically call this method and stop whatever it is doing in an orderly way when this method returns true.
const std::string & name() const;
Returns the task's name.
float progress() const;
Returns the task's progress. The value will be between 0.0 (just started) and 1.0 (completed).
void reset();
Sets the task's progress to zero and clears the cancel flag.
void run();
Calls the task's runTask() method and notifies the owner of the task's start and completion.
See also: Poco::Runnable::run()
virtual void runTask() = 0;
Do whatever the task needs to do. Must be overridden by subclasses.
TaskState state() const;
Returns the task's current state.
TaskManager * getOwner() const;
Returns the owner of the task, which may be NULL.
virtual void postNotification(
Notification * pNf
);
Posts a notification to the task manager's notification center.
A task can use this method to post custom notifications about its progress.
void setOwner(
TaskManager * pOwner
);
Sets the (optional) owner of the task.
void setProgress(
float progress
);
Sets the task's progress. The value should be between 0.0 (just started) and 1.0 (completed).
void setState(
TaskState state
);
Sets the task's state.
bool sleep(
long milliseconds
);
Suspends the current thread for the specified amount of time.
If the task is cancelled while it is sleeping, sleep() will return immediately and the return value will be true. If the time interval passes without the task being cancelled, the return value is false.
A Task should use this method in favor of Thread::sleep().