Class Task

Definition

Namespace:: Tizen.Core

Assembly:: Tizen.Core.dll

Represents the task used for creating, running and terminating the thread with the main loop. The state of the task can be changed as follows: Constructed -> Running -> Terminated. To start the task, use 'Task.Run()' method. Once started, the task enters into 'Running' state. To terminate the task, use 'Task.Quit()' method. After termination, the task returns back to 'Constructed' state.


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public class Task : IDisposable

Inheritance: object

Task

Implements: System.IDisposable

Constructors

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Task(string)

Initializes the Task class with the specified ID.

Declaration


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public Task(string id)

Parameters

Type	Name	Description
string	id	The unique identifier for the task.

Remarks

The constructor throws an exception when the ID already exists. By default, the task creates a separate thread. However, if the id is set to "main", no separate thread is created. In such case, the 'main' task will operate on the main application thread instead.

Examples


                
                
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TizenCore.Initialize();
var task = new Task("Worker");
task.Run();

Exceptions

Type	Condition
System.ArgumentException	Thrown when the `id` is invalid or a Task with that ID already exists.
System.OutOfMemoryException	Thrown when out of memory.
System.InvalidOperationException	Thrown when failed because of an invalid operation.

Properties

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Running

Checks whether the task is running or not.

Declaration


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public bool Running { get; }

Property Value

Type	Description
bool

Methods

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AddChannelReceiver(ChannelReceiver)

Adds a channel receiver to a main loop of the task.

Declaration


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public void AddChannelReceiver(ChannelReceiver receiver)

Parameters

Type	Name	Description
ChannelReceiver	receiver	The channel receiver instance that needs to be added.

Examples

In the following code snippet, we create a channel, find or spawn a task named "ReceivingTask", and then add the channel receiver to the task's main loop by calling the 'AddChannelReceiver' method.


                
                
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var channel = new Channel();
var task = TizenCore.Find("ReceivingTask") ?? TizenCore.Spawn("ReceivingTask");
var receiver = channel.Receiver;
receiver.Received += (sender, args) => {
  Console.WriteLine("OnChannelMessageReceived. Message = " + (string)args.Data);
};
task.AddChannelReceiver(receiver);

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the argument is null.
System.ArgumentException	Thrown when the argument is invalid.
System.InvalidOperationException	Thrown when failed because of an invalid operation.
System.OutOfMemoryException	Thrown when out of memory.

View Source

AddEvent(Event)

Adds an event to a main loop of the task. If the event is successfully added, its unique identifier is assigned to the event. The identifier can then be used later to identify the specific event among others.

Declaration


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public void AddEvent(Event coreEvent)

Parameters

Type	Name	Description
Event	coreEvent	The event instance.

Remarks

This method allows you to associate an event with a specific task. By adding an event to a task's main loop, other threads can utilize this event to communicate with the task. However, note that once an event is attached to a task, it cannot be reused or attached to another task. If the argument passed to this method is null, an exception will be thrown. Additionally, if the event has been previously added, an argument exception will be raised.

Examples


                
                
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var coreEvent = new Event();
coreEvent.EventReceived += (sender, args) => {
  Console.WriteLine("OnEventReceived. ID = {}, Message = {}", args.Id, (string)args.Data);
};

var task = TizenCore.Find("EventTask") ?? TizenCore.Spawn("EventTask");
task.AddEvent(coreEvent);

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the argument is null.
System.ArgumentException	Thrown when the argument is invalid.
System.InvalidOperationException	Thrown when failed because of an invalid operation.
System.OutOfMemoryException	Thrown when out of memory.

View Source

AddTimer(uint, Func<bool>)

Adds a recurring timer to a main loop of the task.

Declaration


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public int AddTimer(uint interval, Func<bool> callback)

Parameters

Type	Name	Description
uint	interval	The interval of the timer in milliseconds.
System.Func<TResult><bool>	callback	The recurring timer callback function which returns whether or not to continue triggering the timer.

Returns

Type	Description
int	The registered timer ID to be used with RemoveTimer(int).

Remarks

The callback function will be called every time the specified interval elapses. It should return true to keep the timer running, otherwise the timer will be stopped.

Examples


                
                
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var task = TizenCore.Find("TimerTask") ?? TizenCore.Spawn("TimerTask");
var timerId = task.AddTimer(1000, () => {
  Console.WriteLine("Timer callback is invoked");
  return true;
});

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the callback argument is null.
System.InvalidOperationException	Thrown when failed because of an invalid operation.
System.OutOfMemoryException	Thrown when out of memory.

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Dispose()

Release any unmanaged resources used by this object.

Declaration


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public void Dispose()

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Dispose(bool)

Release any unmanaged resources used by this object.

Declaration


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protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
bool	disposing	If true, disposes any disposable objects. If false, does not dispose disposable objects.

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EmitEvent(EventObject)

Emits the event object to all registered event handlers of the task. It's similar to Event.Emit(), but EmitAllEvent() sends the event object to every event handler of the task while Event.Emit() sends the event object only to the target event's event handler.

Declaration


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public void EmitEvent(EventObject eventObject)

Parameters

Type	Name	Description
EventObject	eventObject	The event object instance to be sent.

Examples


                
                
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int id = 0;
string message = "Test Event";
using (var eventObject = new TCoreEventObject(id++, message))
{
  var task = TizenCore.Find("EventTask") ?? TizenCore.Spawn("EventTask");
  task.EmitEvent(eventObject);
}

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the argument is null.
System.ArgumentException	Thrown when the argument is invalid.
System.InvalidOperationException	Thrown when failed because of an invalid operation.

View Source

~Task()

Finalizes the Task class.

Declaration


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protected ~Task()

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Post(Action)

Posts an action to be executed later.

Declaration


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public void Post(Action action)

Parameters

Type	Name	Description
System.Action	action	The action callback to post.

Remarks

The action callback will be executed by the main loop of the task. If there was any error during this process, an appropriate exception will be thrown. In order to prevent the action from throwing an exception, you should add a try/catch block. If not, it may cause the application to crash or terminate.

Examples


                
                
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var task = TizenCore.Find("Test") ?? TizenCore.Spawn("Test");
task.Post(() =>
{
  Console.WriteLine("Test task");
});

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the action argument is null.
System.InvalidOperationException	Thrown when failed because of an invalid operation.
System.OutOfMemoryException	Thrown when out of memory.

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Post(Func<Task>)

Posts a task to be executed later.

Declaration


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public void Post(Func<Task> task)

Parameters

Type	Name	Description
System.Func<TResult><System.Threading.Tasks.Task>	task	The task to post.

Remarks

The task will be stored in the internal map using its unique identifier. Then it will be added as an idle job to the main loop of the task. If there was any error during this process, the task will be removed from the map and an appropriate exception will be thrown. In order to prevent the task from throwing an exception, you should add a try/catch block. If not, it may cause the application to crash or terminate.

Examples


                
                
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var channel = new Channel();
var task = TizenCore.Find("Sender") ?? TizenCore.Spawn("Sender");

int id = 0;
task.Post(async () =>
{
  var channelObject = await channel.Receiver.Receive();
  var message = (string)channelObject.Data;
  Console.WriteLine("Received message = " + message);
});

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the task argument is null.
System.InvalidOperationException	Thrown when failed because of an invalid operation.
System.OutOfMemoryException	Thrown when out of memory.

View Source

Quit()

Quits the main loop of the task.

Declaration


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public void Quit()

Remarks

This function can be called from any thread. It requests the task to finish the current iteration of its loop and stop running. All pending events in the event queue will be processed before quitting. Once the task quits, it's finished. To start another task, you need to create a new one and call the Run() method on it.

Examples


                
                
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var coreTask = new TCoreTask("Runner");
coreTask.Run();
if (coreTask.Running)
{
  coreTask.Quit();
}

Exceptions

Type	Condition
System.InvalidOperationException	Thrown when failed because of an invalid operation.

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RemoveChannelReceiver(ChannelReceiver)

Removes the registered channel receiver from the main loop of the task.

Declaration


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public void RemoveChannelReceiver(ChannelReceiver receiver)

Parameters

Type	Name	Description
ChannelReceiver	receiver	The channel receiver instance.

Examples


                
                
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var channel = new Channel();
var task = TizenCore.Find("ReceivingTask") ?? TizenCore.Spawn("ReceivingTask");
var receiver = channel.Receiver;
receiver.Received += (sender, args) => {
  Console.WriteLine("OnChannelMessageReceived. Message = " + (string)args.Data);
};

task.AddChannelReceiver(receiver);
task.RemoveChannelReceiver(receiver);

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the argument is null.
System.ArgumentException	Thrown when the argument is invalid.

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RemoveEvent(Event)

Removes the registered event from the main loop of the task.

Declaration


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public void RemoveEvent(Event coreEvent)

Parameters

Type	Name	Description
Event	coreEvent	The event instance.

Examples


                
                
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var coreEvent = new Event();
coreEvent.EventReceived += (sender, args) => {
  Console.WriteLine("OnEventReceived. ID = {}, Message = {}", args.Id, (string)args.Data);
};

var task = TizenCore.Find("EventTask") ?? TizenCore.Spawn("EventTask");
task.AddEvent(coreEvent);
task.RemoveEvent(coreEvent);

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when the argument is null.
System.ArgumentException	Thrown when the argument is invalid.

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RemoveTimer(int)

Removes the registered timer from the main loop of the task. If the specified timer was already stopped, no action occurs.

Declaration


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public void RemoveTimer(int id)

Parameters

Type	Name	Description
int	id	The registered timer ID.

Examples


                
                
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var task = TizenCore.Find("TimerTask") ?? TizenCore.Spawn("TimerTask");
var timerId = task.AddTimer(1000, () => {
  Console.WriteLine("Timer handler is invoked");
  return true;
});
...
task.RemoveTimer(timerId);

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Run()

Runs the main loop of the task.

Declaration


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public void Run()

Examples

Here's an example that demonstrates how to create a Core Task and run its main loop:


                
                
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// Create a Core Task named "Runner"
var coreTask = new TCoreTask("Runner");

// Start the main loop of the task
coreTask.Run();

Exceptions

Type	Condition
System.InvalidOperationException	Thrown when failed because of an invalid operation.

Implements

System.IDisposable