pt.runtime
Class TaskID<E>

java.lang.Object
  pt.runtime.TaskID<E>

Type Parameters:

E - The task's return type

Direct Known Subclasses:

TaskIDGroup

public class TaskID<E>
extends java.lang.Object

A future object representing a task invocation. As well as containing the return result for non-void tasks, the TaskID may also be used with dependsOn, cancel attempts, and other various functions.

Author:

Nasser Giacaman, Oliver Sinnen

Field Summary

protected boolean	cancelled
protected static int	CANCELLED
protected java.util.concurrent.atomic.AtomicBoolean	cancelRequested
protected static int	CREATED
protected TaskID<?>	enclosingTask
protected int	globalID
protected TaskIDGroup	group
protected java.util.concurrent.atomic.AtomicBoolean	hasCompleted
protected boolean	hasSlots
protected java.util.concurrent.atomic.AtomicBoolean	hasUserError
protected static java.util.concurrent.atomic.AtomicInteger	nextGlobalID
protected int	relativeID
protected static int	STARTED
protected java.util.concurrent.atomic.AtomicInteger	status
protected TaskInfo	taskInfo

Method Summary

boolean	cancelAttempt() Attempts to cancel the task.
protected void	cancelChildTasks() For internal use only.
boolean	cancelledSuccessfully() Checks to see if this task has successfully cancelled.
boolean	cancelRequested() Checks to see if this task has been requested to cancel.
protected boolean	currentThreadIsTheRegisteredThread()
protected int	executeIntermediateSlots()
protected int	executeSlots()
protected int	getCount()
java.lang.Throwable	getException() Returns the exception that occurred while this task executed.
protected Slot	getExceptionHandler(java.lang.Class occurredException)
TaskIDGroup	getGroup() Returns the group that this task is part of (assuming it is a multi-task).
java.util.concurrent.BlockingQueue<E>	getOutputQueue() If this is a pipeline stage, get a queue from which all future results can be retrieved.
protected java.util.concurrent.BlockingQueue<E>	getOutputQueue(TaskID requester) If this is a pipeline stage, get a queue from which all future results can be retrieved.
int	getProgress() Returns the current progress of this task
E	getReturnResult() Returns the result of the task.
java.lang.Object[]	getTaskArguments() Returns the arguments that were passed to this task when it was invoked.
java.lang.String	getTaskName() Returns the (method) name of the task.
int	globalID() Returns the task's globally-unique ID.
boolean	hasCompleted() Checks to see whether the task has completed.
boolean	hasUserError() Checks to see whether the task had any errors.
boolean	isInteractive() Checks to see if this task is an interactibe task.
boolean	isMultiTask() Checks to see if this task is part of a multi-task group.
boolean	isPipeline() Checks to see if this task if a part of a pipeline.
protected boolean	isSubTask()
int	multiTaskSize() Returns the size of the multi-task this task is part of.
int	relativeID() Returns the sub-task's relative ID in the multi-task.
protected void	setCount(int count)
protected void	setGlobalID(int globalID)
protected void	setPipelineThread(PipelineThread pt) Assigns the thread for this stage of the pipeline.
protected void	setSubTask(boolean isSubTask)
protected void	unregisterOutputQueue( queue) Unregisters a queue from a pipeline stage so that new results are no longer written to it.
void	waitTillFinished() Blocks the current thread until the task finishes.
protected void	writeToOutputQueues(E value) Write something into the output queue(s) handled by this TaskID.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

nextGlobalID

protected static java.util.concurrent.atomic.AtomicInteger nextGlobalID

globalID

protected int globalID

relativeID

protected int relativeID

enclosingTask

protected TaskID<?> enclosingTask

taskInfo

protected TaskInfo taskInfo

hasCompleted

protected java.util.concurrent.atomic.AtomicBoolean hasCompleted

cancelled

protected boolean cancelled

cancelRequested

protected java.util.concurrent.atomic.AtomicBoolean cancelRequested

hasUserError

protected java.util.concurrent.atomic.AtomicBoolean hasUserError

group

protected TaskIDGroup group

hasSlots

protected boolean hasSlots

CREATED

protected static final int CREATED

See Also:

Constant Field Values

CANCELLED

protected static final int CANCELLED

See Also:

Constant Field Values

STARTED

protected static final int STARTED

See Also:

Constant Field Values

status

protected java.util.concurrent.atomic.AtomicInteger status

Method Detail

getCount

protected int getCount()

setCount

protected void setCount(int count)

isSubTask

protected boolean isSubTask()

setSubTask

protected void setSubTask(boolean isSubTask)

cancelledSuccessfully

public boolean cancelledSuccessfully()

Checks to see if this task has successfully cancelled.

Returns:

true if it has cancelled successfully, false otherwise.

isInteractive

public boolean isInteractive()

Checks to see if this task is an interactibe task.

Returns:

true if this is an interactive task, false otherwise.

isPipeline

public boolean isPipeline()

Checks to see if this task if a part of a pipeline.

setPipelineThread

protected void setPipelineThread(PipelineThread pt)

Assigns the thread for this stage of the pipeline. Used for cancelling the stage via PipelineThread.cancel().

getOutputQueue

public java.util.concurrent.BlockingQueue<E> getOutputQueue()

If this is a pipeline stage, get a queue from which all future results can be retrieved. If not, returns null. Thread-safe.

getOutputQueue

protected java.util.concurrent.BlockingQueue<E> getOutputQueue(TaskID requester)

If this is a pipeline stage, get a queue from which all future results can be retrieved. If not, returns null. Intended for internal use only. Must pass the TaskID of the task requesting the queue in order to associate the queue with the tasks it connects. Thread-safe.

unregisterOutputQueue

protected void unregisterOutputQueue( queue)

Unregisters a queue from a pipeline stage so that new results are no longer written to it. Also, releases the reference so it can be GC'd. For internal use only. Thread-safe.

writeToOutputQueues

protected void writeToOutputQueues(E value)

Write something into the output queue(s) handled by this TaskID. Only existing queues will get the object. Thread-safe.

cancelChildTasks

protected void cancelChildTasks()

For internal use only. Cancel all child stages if this is a pipeline.

getProgress

public int getProgress()

Returns the current progress of this task

Returns:

The task's current progress.

See Also:

CurrentTask.getProgress(), CurrentTask.setProgress(int), setProgress(int)

cancelRequested

public boolean cancelRequested()

Checks to see if this task has been requested to cancel.

Returns:

true if it has been requested to cancel, false otherwise.

See Also:

CurrentTask.cancelRequested(), cancelAttempt(), cancelledSuccessfully()

cancelAttempt

public boolean cancelAttempt()

Attempts to cancel the task. If cancelled successfully, the task will not be enqueued. A failed cancel will still allow the task to continue executing. To stop the task, the task should check to see if a cancel request has been made.

Returns:

true if it has cancelled successfully, false otherwise.

See Also:

cancelRequested(), CurrentTask.cancelRequested(), cancelledSuccessfully()

getGroup

public TaskIDGroup getGroup()

Returns the group that this task is part of (assuming it is a multi-task).

Returns:

Returns the group associated with this task. If not part of a multi-task, then returns null.

getTaskName

public java.lang.String getTaskName()

Returns the (method) name of the task.

Returns:

globalID

public int globalID()

Returns the task's globally-unique ID.

Returns:

The task's unique ID.

See Also:

CurrentTask.globalID(), CurrentTask.relativeID(), relativeID()

relativeID

public int relativeID()

Returns the sub-task's relative ID in the multi-task.

Returns:

The position, starting from 0, of this sub-task compared to it's sibling subtasks.

See Also:

CurrentTask.globalID(), CurrentTask.relativeID(), globalID()

getReturnResult

public E getReturnResult()
                  throws java.util.concurrent.ExecutionException,
                         java.lang.InterruptedException

Returns the result of the task. If the task has not finished yet, the current thread blocks. ParaTask worker threads will not block, instead they execute other ready tasks until this task completes.

Returns:

The result of the task.

Throws:

java.util.concurrent.ExecutionException

java.lang.InterruptedException

waitTillFinished

public void waitTillFinished()
                      throws java.util.concurrent.ExecutionException,
                             java.lang.InterruptedException

Blocks the current thread until the task finishes. If the blocking thread is a ParaTask worker thread, then other tasks are executed until this task completes.

Throws:

java.util.concurrent.ExecutionException

java.lang.InterruptedException

Since:

25/05/2013 Before a worker tries to find another task and executes it, this thread should check if there is cancel request. If a worker thread is poisoned, even there are some unfinished children tasks, it will not get a chance to execute them, what it can do is check if they are finished or not(executed by other thread), 31/05/2013 Simplify the implementation of reducing thread number. Do not need to access the "PoisonPillBox" to get a "pill" Instead, using the class of "LottoBox"

currentThreadIsTheRegisteredThread

protected boolean currentThreadIsTheRegisteredThread()

getException

public java.lang.Throwable getException()

Returns the exception that occurred while this task executed.

Returns:

The exception that occurred.

hasCompleted

public boolean hasCompleted()

Checks to see whether the task has completed.

Returns:

true if it has completed, false otherwise

See Also:

getProgress(), CurrentTask.getProgress()

hasUserError

public boolean hasUserError()

Checks to see whether the task had any errors.

Returns:

true if there was an error, false otherwise

getExceptionHandler

protected Slot getExceptionHandler(java.lang.Class occurredException)

executeIntermediateSlots

protected int executeIntermediateSlots()

executeSlots

protected int executeSlots()

getTaskArguments

public java.lang.Object[] getTaskArguments()

Returns the arguments that were passed to this task when it was invoked.

Returns:

The arguments initially passed to the task when it was invoked

isMultiTask

public boolean isMultiTask()

Checks to see if this task is part of a multi-task group.

Returns:

true if this task is part of a multi-task, false otherwise

multiTaskSize

public int multiTaskSize()

Returns the size of the multi-task this task is part of.

Returns:

The multi-task size, otherwise returns 1 if this task is not part of a multi-task.

setGlobalID

protected void setGlobalID(int globalID)

Since:

: 10/05/2013 When multi task is expanded, call this method, and set global id for its sub tasks.