public void DependentParallelTask()
{
// Reset the counter, the tasks will update this.
Thread.VolatileWrite(ref _counter, 0);
// Create an boundary that will ensure all tasks complete before exiting.
using (TaskBoundary boundary = new TaskBoundary())
{
// Create two tasks...
ParallelTask firstTask = new ParallelActionWrapper<ThreadPoolExecutionStrategy>(this.WaitForTwoSeconds);
ParallelTask secondTask = new ParallelActionWrapper<ThreadPoolExecutionStrategy>(this.WaitForTwoSeconds);
Assert.IsTrue(firstTask.IsIdle);
Assert.IsTrue(secondTask.IsIdle);
// Start the first task, it will take 2 seconds to complete.
firstTask.AsyncExecute();
Assert.IsTrue(firstTask.IsPending | firstTask.IsExecuting, "task state should be Pending or Executing");
Assert.IsTrue(secondTask.IsIdle, "task state should be Idle");
// Schedule the second task to start when the first task completes.
// The timeout is set to 10 seconds just in case the first task
// fails to complete. You can also use Timeout.Infinite.
secondTask.ScheduledExecute(firstTask, TimeSpan.FromSeconds(10));
Assert.IsTrue(secondTask.IsPending | secondTask.IsExecuting, "task state should be Pending or Executing");
Assert.IsTrue(secondTask.IsScheduled | secondTask.IsExecuting, "task state should be Scheduled or Executing");
// We should get here in milliseconds, so the counter should not
// be incremented yet. If it is then one of the above calls was
// a blocking call, which is an error.
Assert.AreEqual(0, Thread.VolatileRead(ref _counter), "Counter should not have incremented already");
// Wait for the second task to complete. This will take slightly
// longer than 4 seconds.
secondTask.WaitForCompletion();
Assert.IsTrue(firstTask.IsCompletedSuccess);
Assert.IsTrue(secondTask.IsCompletedSuccess);
boundary.MarkCompleted();
}
// And now the counter should have been incremented by both tasks.
Assert.AreEqual(2, Thread.VolatileRead(ref _counter));
}
public ParallelTask(AsyncCallback callback, object handback)
{
_callback = callback;
_handback = handback;
_boundary = TaskBoundary.AddTask(this);
}
public void IndependentParallelTask_FireAndForget()
{
// Reset the counter, the tasks will update this.
Thread.VolatileWrite(ref _counter, 0);
using (TaskBoundary boundary = new TaskBoundary())
{
// Create and execute one task that waits two seconds before it completes.
ParallelTask task = new ParallelActionWrapper<ThreadPoolExecutionStrategy>(this.FireAndForget);
Assert.IsTrue(task.IsIdle);
task.AsyncExecute();
Assert.IsTrue(task.IsPending | task.IsExecuting, "task state should be Pending or Executing");
// The counter will increment after the fire and forget tasks execute.
Assert.AreEqual(0, Thread.VolatileRead(ref _counter), "Counter should not have incremented already");
// Wait for the task to complete.
task.WaitForCompletion();
Assert.IsTrue(task.IsCompletedSuccess);
boundary.MarkCompleted();
}
// And now the counter should have been incremented by the two fire and forget tasks.
Assert.AreEqual(2, Thread.VolatileRead(ref _counter));
}
public void DependentParallelTask_SecondTaskTimeoutBeforeFirstTaskCompletes()
{
// Reset the counter, the tasks will update this.
Thread.VolatileWrite(ref _counter, 0);
try
{
// Create an boundary that will ensure all tasks complete before exiting.
using (TaskBoundary boundary = new TaskBoundary())
{
// Create two tasks...
ParallelTask firstTask = new ParallelActionWrapper<ThreadPoolExecutionStrategy>(this.WaitForTwoSeconds);
ParallelTask secondTask = new ParallelActionWrapper<ThreadPoolExecutionStrategy>(this.WaitForTwoSeconds);
Assert.IsTrue(firstTask.IsIdle);
Assert.IsTrue(secondTask.IsIdle);
// Schedule the second task to start when the first task completes.
// The timeout is set to 1 second so that it times out before
// the first task completes.
secondTask.ScheduledExecute(firstTask, TimeSpan.FromSeconds(1));
Assert.IsTrue(secondTask.IsPending, "task state should be Pending");
Assert.IsTrue(secondTask.IsScheduled, "task state should be Scheduled");
Assert.IsTrue(firstTask.IsIdle);
// Start the first task, it will take 2 seconds to complete.
firstTask.AsyncExecute();
Assert.IsTrue(firstTask.IsPending | firstTask.IsExecuting, "task state should be Pending or Executing");
// We should get here in milliseconds, so the counter should not
// be incremented yet. If it is then one of the above calls was
// a blocking call, which is an error.
Assert.AreEqual(0, Thread.VolatileRead(ref _counter), "Counter should not have incremented already");
try
{
// Wait for the second task to complete. This will take slightly
// longer than 1 second and a TimeoutException is thrown.
secondTask.WaitForCompletion();
Assert.Fail("The dependent task should have thrown an ParallelTimeoutException");
}
finally
{
// We expected the error and want the first task to complete.
boundary.MarkCompleted();
}
}
}
catch (ParallelTimeoutException)
{
// And now the counter should have been incremented by the first task before
// exiting the boundary.
Assert.AreEqual(1, Thread.VolatileRead(ref _counter));
throw;
}
}
