|
258
|
1 using System;
|
|
|
2 using System.Threading;
|
|
|
3 using System.Threading.Tasks;
|
|
|
4
|
|
|
5 namespace Implab.Components {
|
|
|
6 public abstract class PollingComponent : RunnableComponent {
|
|
|
7
|
|
|
8 readonly Timer m_timer;
|
|
|
9
|
|
|
10 readonly CancellationTokenSource m_cancellation = new CancellationTokenSource();
|
|
|
11
|
|
259
|
12 Task m_pending;
|
|
|
13 Task m_poll;
|
|
|
14
|
|
258
|
15 /// <summary>
|
|
|
16 /// Poll interval in milliseconds.
|
|
|
17 /// </summary>
|
|
|
18 /// <returns></returns>
|
|
|
19 public int Interval { get; set; }
|
|
|
20
|
|
|
21 /// <summary>
|
|
|
22 /// Delay to the first poll after start in milliseconds
|
|
|
23 /// </summary>
|
|
|
24 /// <returns></returns>
|
|
|
25 public int Delay { get; set; }
|
|
|
26
|
|
|
27 /// <summary>
|
|
|
28 /// Indicates how to handle unhandled exceptions in <see cref="Poll()"/> method.
|
|
|
29 /// </summary>
|
|
|
30 /// <returns></returns>
|
|
|
31 public bool FailOnError { get; set; }
|
|
|
32
|
|
|
33 /// <summary>
|
|
|
34 /// Event for the unhandled exceptions in <see cref="Poll()"/> method.
|
|
|
35 /// </summary>
|
|
|
36 public event EventHandler<UnhandledExceptionEventArgs> UnhandledException;
|
|
|
37
|
|
|
38 protected PollingComponent(bool initialized) : base(initialized) {
|
|
|
39 m_timer = new Timer(OnTimer);
|
|
|
40 }
|
|
|
41
|
|
|
42 protected override void RunInternal() {
|
|
|
43 ScheduleNextPoll(Delay);
|
|
|
44 }
|
|
|
45
|
|
|
46
|
|
259
|
47 protected override async Task StopInternalAsync(CancellationToken ct) {
|
|
|
48 // component in Stopping state, no new polls will be scheduled
|
|
|
49 m_cancellation.Cancel();
|
|
|
50 try {
|
|
|
51 // await for pending poll
|
|
262
|
52 if (m_poll != null)
|
|
|
53 await m_poll;
|
|
260
|
54 } catch (OperationCanceledException) {
|
|
259
|
55 // OK
|
|
|
56 }
|
|
|
57 }
|
|
258
|
58
|
|
|
59 protected abstract Task Poll(CancellationToken ct);
|
|
|
60
|
|
|
61 void ScheduleNextPoll(int timeout) {
|
|
|
62 lock (SynchronizationObject) {
|
|
259
|
63 if (State == ExecutionState.Running) {
|
|
|
64 m_pending = Safe.CreateTask(m_cancellation.Token);
|
|
|
65 m_poll = m_pending.Then(() => Poll(m_cancellation.Token));
|
|
258
|
66 m_timer.Change(timeout, Timeout.Infinite);
|
|
259
|
67 }
|
|
258
|
68 }
|
|
|
69 }
|
|
|
70
|
|
259
|
71 async void OnTimer(object state) {
|
|
258
|
72 try {
|
|
259
|
73 m_pending.Start();
|
|
|
74 await m_poll;
|
|
260
|
75 ScheduleNextPoll(Interval);
|
|
258
|
76 } catch (Exception e) {
|
|
|
77 UnhandledException.DispatchEvent(this, new UnhandledExceptionEventArgs(e, false));
|
|
260
|
78
|
|
258
|
79 if (FailOnError)
|
|
|
80 Fail(e);
|
|
260
|
81 else
|
|
|
82 ScheduleNextPoll(Interval);
|
|
258
|
83 }
|
|
260
|
84
|
|
258
|
85 }
|
|
|
86
|
|
|
87 protected override void Dispose(bool disposing) {
|
|
|
88 if (disposing)
|
|
|
89 Safe.Dispose(m_timer, m_cancellation);
|
|
|
90 base.Dispose(disposing);
|
|
|
91 }
|
|
|
92
|
|
|
93 }
|
|
|
94 } |
