public void CopyTo()
{
// Create a new priority queue.
ConcurrentPriorityQueue <int> queue = new ConcurrentPriorityQueue <int>();
// Create a new array of size 5.
PriorityValuePair <int>[] arrayCopy = new PriorityValuePair <int> [5];
// Enqueue 3 elements into the queue.
PriorityValuePair <int> elem = new PriorityValuePair <int>(3.0, 6);
queue.Enqueue(1.0, 2);
queue.Enqueue(elem);
queue.Enqueue(2.0, 4);
// Copy the queue data to the array, starting from index 1 (not 0).
queue.CopyTo(arrayCopy, 1);
// Expect the first array index to be unset, but all the rest to be set.
// Note: The order of elements after the first can't be guaranteed, because the heap
// implementing the queue internally doesn't store things in an exact linear order,
// but we can be sure that the elements aren't going to be equal to null because we
// set them.
Assert.That(arrayCopy[0], Is.EqualTo(null));
Assert.That(arrayCopy[1], Is.EqualTo(elem));
Assert.That(arrayCopy[2], Is.Not.EqualTo(null));
Assert.That(arrayCopy[3], Is.Not.EqualTo(null));
Assert.That(arrayCopy[4], Is.EqualTo(null));
}
Enqueue(double priority, WaitCallback callback, object context = null)
{
if (IsStopping)
{
// We want to block new tasks from being queued while the task runner is trying to
// shut down, so that it can successfully stop instead of being bogged down by new
// tasks forever.
throw new InvalidOperationException("Cannot enqueue tasks while the task runner is stopping.");
}
// Create a new task, wrap it in a PriorityValuePair, and enqueue it.
Task task = new Task(context, callback);
PriorityValuePair <Task> elem = new PriorityValuePair <Task>(priority, task);
__queue.Enqueue(elem);
// Mark the task as waiting to complete.
onWaitingTask(elem);
// Subscribe an event listener to the task's CallbackReturned event that will release
// the task resources and allow another to run.
ManualResetEvent resetEvent = new ManualResetEvent(false);
task.TaskComplete += delegate {
onCompletedTask(elem);
resetEvent.Set();
};
// Return the ManualResetEvent to the caller so they can be aware of when this task
// finishes execution.
return(resetEvent);
}
public void PopValue()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Try to PopPriority() and expect an NullReferenceException to be thrown.
Assert.Throws <NullReferenceException>(() => {
heap.PopValue();
});
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Store an element and insert it into the heap.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1f, 2);
heap.Push(elem);
// Ensure that the element was inserted into the heap.
Assert.That(heap.Peek(), Is.EqualTo(elem));
// Ensure that the value of the pushed element is returned.
Assert.That(heap.PopValue(), Is.EqualTo(2));
// Ensure that the element was removed from the heap.
Assert.That(heap.Count, Is.EqualTo(0));
}
public void Remove()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Create and store a few elements.
PriorityValuePair <int> elem1 = new PriorityValuePair <int>(1f, 2);
PriorityValuePair <int> elem2 = new PriorityValuePair <int>(2f, 4);
PriorityValuePair <int> elem3 = new PriorityValuePair <int>(3f, 6);
// Expect Remove() to return null for an empty heap.
Assert.That(heap.Remove(elem1), Is.EqualTo(false));
// Insert 2 of the elements into the heap.
heap.Push(elem2);
heap.Push(elem3);
// Expect Remove() to return false for elem1, indicating the element was removed
// (since it doesn't belong to the heap and can't be found). This tests the if-else
// case for when the provided element isn't found in the heap.
Assert.That(heap.Remove(elem1), Is.False);
// Expect Remove() to return true for elem2, indicating the element was removed
// (since it belongs to the heap and can be found). This tests the if-else case for
// when Count is 2 or greater.
Assert.That(heap.Remove(elem2), Is.True);
// Expect Remove() to return true for elem3, indicating the element was removed
// (since it belongs to the heap and can be found). This tests the if-else case for
// when Count equals 1.
Assert.That(heap.Remove(elem3), Is.True);
}
public void Pop()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Expect Pop() to return null for an empty heap.
Assert.That(heap.Pop(), Is.EqualTo(null));
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Store an element and insert it into the heap.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1f, 2);
heap.Push(elem);
// Ensure that the element was inserted into the heap.
Assert.That(heap.Count, Is.EqualTo(1));
Assert.That(heap.Peek(), Is.EqualTo(elem));
// Ensure that the returned element points to the same object we stored earlier.
Assert.That(heap.Pop(), Is.EqualTo(elem));
// Ensure that the element was removed from the heap.
Assert.That(heap.Count, Is.EqualTo(0));
}
public void Peek()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Expect Peek() to return null for an empty heap.
Assert.That(heap.Peek(), Is.EqualTo(null));
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Store an element and insert it into the heap.
PriorityValuePair <int> elem1 = new PriorityValuePair <int>(1f, 2);
heap.Push(elem1);
// Ensure that the element was inserted into the heap as the root element.
Assert.That(heap.Count, Is.EqualTo(1));
Assert.That(heap.Peek(), Is.EqualTo(elem1));
// Ensure that the element was not removed from the heap.
Assert.That(heap.Count, Is.EqualTo(1));
// Insert another element with higher priority than the last.
PriorityValuePair <int> elem2 = new PriorityValuePair <int>(2f, 4);
heap.Push(elem2);
// Ensure that Peak() returns the new root element.
Assert.That(heap.Peek(), Is.EqualTo(elem2));
}
public void CopyTo()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Create a new array of size 5.
PriorityValuePair <int>[] arrayCopy = new PriorityValuePair <int> [5];
// Push 3 elements onto the queue.
PriorityValuePair <int> elem = new PriorityValuePair <int>(3f, 6);
heap.Push(1f, 2);
heap.Push(elem);
heap.Push(2f, 4);
// Copy the heap data to the array, starting from index 1 (not 0).
heap.CopyTo(arrayCopy, 1);
// Expect the first array index to be unset, but all the rest to be set.
// Note: The order of elements after the first can't be guaranteed, because the heap
// doesn't store things in an exact linear order, but we can be sure that the elements
// aren't going to be equal to null because we set them.
Assert.That(arrayCopy[0], Is.EqualTo(null));
Assert.That(arrayCopy[1], Is.EqualTo(elem));
Assert.That(arrayCopy[2], Is.Not.EqualTo(null));
Assert.That(arrayCopy[3], Is.Not.EqualTo(null));
Assert.That(arrayCopy[4], Is.EqualTo(null));
}
public void Remove()
{
// Create a new priority queue.
ConcurrentPriorityQueue <int> queue = new ConcurrentPriorityQueue <int>();
// Create and store a few elements.
PriorityValuePair <int> elem1 = new PriorityValuePair <int>(1.0, 2);
PriorityValuePair <int> elem2 = new PriorityValuePair <int>(2.0, 4);
PriorityValuePair <int> elem3 = new PriorityValuePair <int>(3.0, 6);
// Expect Remove() to return false for an empty queue.
Assert.That(queue.Remove(elem1), Is.False);
// Enqueue 2 of the elements into the heap.
queue.Enqueue(elem2);
queue.Enqueue(elem3);
// Expect Remove() to return false for elem1, indicating the element was removed
// (since it doesn't belong to the heap and can't be found). This tests the if-else
// case for when the provided element isn't found in the heap.
Assert.That(queue.Remove(elem1), Is.False);
// Expect Remove() to return true for elem2, indicating the element was removed
// (since it belongs to the heap and can be found). This tests the if-else case for
// when Count is 2 or greater.
Assert.That(queue.Remove(elem2), Is.True);
// Expect Remove() to return true for elem3, indicating the element was removed
// (since it belongs to the heap and can be found). This tests the if-else case for
// when Count equals 1.
Assert.That(queue.Remove(elem3), Is.True);
}
ThreadProc()
{
// Change state to indicate that the task runner is started.
__state = TaskRunnerState.Running;
// Emit an event to notify listeners that the task runner started up.
if (Started != null)
{
Started();
}
// Continue looping until Stop() is called and all critical tasks are finished.
while (!IsStopping || IsStopping && HasEnqueuedCriticalTasks)
{
// Most of this is only important if something is in the queue.
if (RunningTasks < ThreadPoolMaxThreads && __queue.Peek() != null)
{
// Execute the task on the thread pool.
PriorityValuePair <Task> elem = __queue.Dequeue();
Task task = elem.Value;
if (task != null)
{
// We're passing a null context here because the task is packaged with its
// own execution context that will be inserted during Task.Run().
ThreadPool.QueueUserWorkItem((x) => { task.Run(); }, null);
}
// Mark the task as starting execution.
// Note: This should run even if the task is null above, otherwise the counts
// for the number of running/waiting tasks will become skewed.
onRunningTask(elem);
}
else
{
// Yield the rest of the time slice.
Thread.Sleep(1);
}
}
// Wait for all critical tasks to finish running before stopping.
while (HasWaitingCriticalTasks)
{
Thread.Sleep(1);
}
// Flag the task runner as stopped.
__state = TaskRunnerState.Stopped;
__thread = null;
// Emit an event to notify listeners that the task runner stopped.
if (Stopped != null)
{
Stopped();
}
}
public void Dequeue()
{
// Create a new priority queue.
ConcurrentPriorityQueue <int> queue = new ConcurrentPriorityQueue <int>();
// Ensure that the heap is empty.
Assert.That(queue.Count, Is.EqualTo(0));
// Expect Dequeue() to return null for an empty heap.
Assert.That(queue.Dequeue(), Is.EqualTo(null));
// Ensure that the heap is empty.
Assert.That(queue.Count, Is.EqualTo(0));
// Store an element and insert it into the heap.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1.0, 2);
queue.Enqueue(elem);
// Ensure that the element was inserted into the heap.
Assert.That(queue.Count, Is.EqualTo(1));
Assert.That(queue.Peek(), Is.EqualTo(elem));
// Ensure that the PriorityAdjustment was incremented.
Assert.That(queue.PriorityAdjustment, Is.EqualTo(ConcurrentPriorityQueue <int> .EPSILON));
// Ensure that the returned element points to the same object we stored earlier.
Assert.That(queue.Dequeue(), Is.EqualTo(elem));
// Ensure that the element was removed from the heap.
Assert.That(queue.Count, Is.EqualTo(0));
// Ensure that the PriorityAdjustment was reset once the queue became empty.
Assert.That(queue.PriorityAdjustment, Is.EqualTo(0.0));
// Enqueue 5 items with the same priority.
PriorityValuePair <int> elem2 = new PriorityValuePair <int>(2.0, 0);
PriorityValuePair <int> elem3 = new PriorityValuePair <int>(2.0, 2);
PriorityValuePair <int> elem4 = new PriorityValuePair <int>(2.0, 4);
PriorityValuePair <int> elem5 = new PriorityValuePair <int>(2.0, 6);
PriorityValuePair <int> elem6 = new PriorityValuePair <int>(2.0, 8);
queue.Enqueue(elem2);
queue.Enqueue(elem3);
queue.Enqueue(elem4);
queue.Enqueue(elem5);
queue.Enqueue(elem6);
//// Ensure that Dequeue() returns the items in the order they were enqueued.
Assert.That(queue.Dequeue(), Is.EqualTo(elem2));
Assert.That(queue.Dequeue(), Is.EqualTo(elem3));
Assert.That(queue.Dequeue(), Is.EqualTo(elem4));
Assert.That(queue.Dequeue(), Is.EqualTo(elem5));
Assert.That(queue.Dequeue(), Is.EqualTo(elem6));
}
onRunningTask(PriorityValuePair <Task> elem)
{
#region Increment counters
// Based on its priority, increment the appropriate active counter.
if (elem.Priority >= MinCriticalPriority)
{
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__runningCriticalTasksLock);
try
{
__runningCriticalTasks++;
}
finally
{
Monitor.Exit(__runningCriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
}
else
{
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__runningNoncriticalTasksLock);
try
{
__runningNoncriticalTasks++;
}
finally
{
Monitor.Exit(__runningNoncriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
}
#endregion
#region Emit events
// Emit an event to notify listeners that a task has begun executing.
if (TaskStarted != null)
{
TaskStarted();
}
// Emit an event to notify listeners that the queue is empty (if so).
if (QueueEmpty != null && __queue.Peek() != null)
{
QueueEmpty();
}
#endregion
}
public void SwapElements()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Enqueue an element into the queue.
var elem1 = new PriorityValuePair <int>(2f, 4);
heap.Push(elem1);
// Ensure that the element was inserted.
Assert.That(heap.Count, Is.EqualTo(1));
Assert.That(heap.Peek(), Is.EqualTo(elem1));
// Try to HeapSwapElements() while the queue only contains 1 element and expect an
// InvalidOperationException to be thrown.
Assert.Throws <InvalidOperationException>(() => {
heap.SwapElements(0, 1);
});
// Enqueue another element with higher priority than the last.
var elem2 = new PriorityValuePair <int>(1f, 2);
heap.Push(elem2);
// Ensure that the element was inserted and that the 1st (higher priority) element is
// still at the root of the heap.
Assert.That(heap.Count, Is.EqualTo(2));
Assert.That(heap.Peek(), Is.EqualTo(elem1));
// Try to HeapSwapElements() with an invalid index1 and expect an
// ArgumentOutOfRangeException to be thrown.
Assert.Throws <ArgumentOutOfRangeException>(() => {
heap.SwapElements(-1, 1);
});
// Try to HeapSwapElements() with an invalid index2 and expect an
// ArgumentOutOfRangeException to be thrown.
Assert.Throws <ArgumentOutOfRangeException>(() => {
heap.SwapElements(0, -1);
});
// Actually swap elements now.
heap.SwapElements(0, 1);
// Ensure that the elements were swapped.
Assert.That(heap.Count, Is.EqualTo(2));
Assert.That(heap.Peek(), Is.EqualTo(elem2));
Assert.That(heap.Contains(elem1), Is.True);
}
public void Peek()
{
// Create a new priority queue.
ConcurrentPriorityQueue <int> queue = new ConcurrentPriorityQueue <int>();
// Ensure that the heap is empty.
Assert.That(queue.Count, Is.EqualTo(0));
// Expect Peek() to return null for an empty heap.
Assert.That(queue.Peek(), Is.EqualTo(null));
// Ensure that the queue is empty.
Assert.That(queue.Count, Is.EqualTo(0));
// Store an element and insert it into the queue.
PriorityValuePair <int> elem1 = new PriorityValuePair <int>(1.0, 2);
queue.Enqueue(elem1);
// Ensure that the element was inserted into the queue at the front.
Assert.That(queue.Count, Is.EqualTo(1));
Assert.That(queue.Peek(), Is.EqualTo(elem1));
// Ensure that the element was not removed from the heap.
Assert.That(queue.Count, Is.EqualTo(1));
// Insert another element with higher priority than the last.
PriorityValuePair <int> elem2 = new PriorityValuePair <int>(2.0, 4);
queue.Enqueue(elem2);
// Ensure that Peek() returns the new front element.
Assert.That(queue.Peek(), Is.EqualTo(elem2));
// Insert another element with the same priority as the last.
PriorityValuePair <int> elem3 = new PriorityValuePair <int>(2.0, 6);
queue.Enqueue(elem3);
// Ensure that Peek() returns still returns the first value with that priority.
Assert.That(queue.Peek(), Is.EqualTo(elem2));
// Remove the element from the queue.
queue.Dequeue();
// Ensure that Peek() returns now returns the other value with the same priorty.
Assert.That(queue.Peek(), Is.EqualTo(elem3));
}
public void Contains()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Create and store a new element.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1f, 2);
// Ensure the queue contains the element.
Assert.That(heap.Contains(elem), Is.False);
// Push it onto the heap.
heap.Push(elem);
// Ensure the queue now contains the element.
Assert.That(heap.Contains(elem), Is.True);
}
public void Contains()
{
// Create a new priority queue.
ConcurrentPriorityQueue <int> queue = new ConcurrentPriorityQueue <int>();
// Create and store a new element.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1.0, 2);
// Ensure the queue contains the element.
Assert.That(queue.Contains(elem), Is.False);
// Enqueue it in the queue.
queue.Enqueue(elem);
// Ensure the queue now contains the element.
Assert.That(queue.Contains(elem), Is.True);
}
onWaitingTask(PriorityValuePair <Task> elem)
{
#region Increment counters
// Based on its priority, increment the appropriate waiting counter.
if (elem.Priority >= MinCriticalPriority)
{
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__waitingCriticalTasksLock);
try
{
__waitingCriticalTasks++;
}
finally
{
Monitor.Exit(__waitingCriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
}
else
{
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__waitingNoncriticalTasksLock);
try
{
__waitingNoncriticalTasks++;
}
finally
{
Monitor.Exit(__waitingNoncriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
}
#endregion
#region Emit events
// Emit an event to notify listeners that a task has been enqueued.
if (TaskEnqueued != null)
{
TaskEnqueued();
}
#endregion
}
public void EnqueueElement()
{
// Create a new priority queue.
ConcurrentPriorityQueue <int> queue = new ConcurrentPriorityQueue <int>();
// Ensure that the queue is empty.
Assert.That(queue.Count, Is.EqualTo(0));
// Store an element and insert it into the queue.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1.0, 2);
queue.Enqueue(elem);
// Ensure that the element was inserted into the queue.
Assert.That(queue.Peek(), Is.EqualTo(elem));
// Store another element with higher priority and insert it as well.
elem = new PriorityValuePair <int>(2.0, 4);
queue.Enqueue(elem);
// Ensure that the element was inserted into the queue and is at the front.
Assert.That(queue.Peek(), Is.EqualTo(elem));
}
public void PushElement()
{
// Create a new heap.
ConcurrentBinaryMinHeap <int> heap = new ConcurrentBinaryMinHeap <int>();
// Ensure that the heap is empty.
Assert.That(heap.Count, Is.EqualTo(0));
// Store an element and insert it into the heap.
PriorityValuePair <int> elem = new PriorityValuePair <int>(1f, 2);
heap.Push(elem);
// Ensure that the element was inserted into the heap.
Assert.That(heap.Peek(), Is.EqualTo(elem));
// Store another element with higher priority and insert it as well.
elem = new PriorityValuePair <int>(2f, 4);
heap.Push(elem);
// Ensure that the element was inserted into the queue and is at the root.
Assert.That(heap.Peek(), Is.EqualTo(elem));
}
static void Main(string[] args)
{
ConcurrentPriorityQueue <string> queue = new ConcurrentPriorityQueue <string>();
queue.Enqueue(1000.0, "This ");
queue.Enqueue(1000.0, "should ");
queue.Enqueue(1000.0, "form ");
queue.Enqueue(1000.0, "a ");
queue.Enqueue(1000.0, "complete ");
queue.Enqueue(1000.0, "and ");
queue.Enqueue(1000.0, "understandable ");
queue.Enqueue(1000.0, "sentence.");
int numIterations = queue.Count;
for (int x = 0; x < numIterations; x++)
{
Console.WriteLine("ITERATION " + (x + 1));
Console.WriteLine("");
// Print out the current state of the heap
PriorityValuePair <string>[] heapArray = new PriorityValuePair <string> [queue.Count];
queue.CopyTo(heapArray, 0);
for (int i = 0; i < heapArray.Length; i++)
{
Console.WriteLine(heapArray[i].Value + ", " + heapArray[i].Priority);
}
// Dequeue the next element
PriorityValuePair <string> dequeued = queue.Dequeue();
Console.WriteLine("");
Console.WriteLine("DEQUEUED: " + dequeued.Value + ", " + dequeued.Priority);
Console.WriteLine("");
}
Console.ReadLine();
}
onCompletedTask(PriorityValuePair <Task> elem)
{
#region Decrement counters
// Based on its priority, increment the appropriate active counter.
if (elem.Priority >= MinCriticalPriority)
{
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__runningCriticalTasksLock);
try
{
__runningCriticalTasks--;
}
finally
{
Monitor.Exit(__runningCriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__waitingCriticalTasksLock);
try
{
__waitingCriticalTasks--;
}
finally
{
Monitor.Exit(__waitingCriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
}
else
{
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__runningNoncriticalTasksLock);
try
{
__runningNoncriticalTasks--;
}
finally
{
Monitor.Exit(__runningNoncriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
// Lock the thread -- CRITICAL SECTION BEGIN
Monitor.Enter(__waitingNoncriticalTasksLock);
try
{
__waitingNoncriticalTasks--;
}
finally
{
Monitor.Exit(__waitingNoncriticalTasksLock);
// Unlock the thread -- CRITICAL SECTION END
}
}
#endregion
#region Emit events
// Emit an event to notify listeners that a task has finished executing.
if (TaskCompleted != null)
{
TaskCompleted();
}
// Emit an event to notify listeners that all critical tasks have finished
// executing (if so).
if (__waitingCriticalTasks <= 0)
{
if (CriticalTasksCompleted != null)
{
CriticalTasksCompleted();
}
}
// Emit an event to notify listeners that all tasks have finished executing
// (if so).
if (__waitingCriticalTasks <= 0 && __waitingNoncriticalTasks <= 0)
{
if (AllTasksCompleted != null)
{
AllTasksCompleted();
}
}
#endregion
}
