Cycle through ConcurrentQueue indefinitely using either Timer/Stopwatch based event

Question

In my CheckQueue() method, what I want to do is constantly read from the queue (by calling the AppQ.Connect(Time)) and TryDequeue each item off of it. After some elapsed time (maybe a minute or so), I want to go back to the queue - connect again, check if it has some elements (AppQ.Count), read them (by TryDequeue()) and do this process indefinitely.

This is for an application which will be made a Windows Service (currently a Windows Forms Application for testing purposes) that will run all day everyday and alert us the developers when there is some downtime in any application running on some machine. I know I will have to use a While-Loop but I am unsure whether to use a Timer based event or a Stopwatch along with it.

More context: I also have a feeling that I should consider making use of a do-while loop as opposed to a while seeing as the former performs some action (load messages by calling AppQ.Connect(time)) then check the exit condition (if AppQ.Count <= 0) whereas a while does the opposite.

Should I use a BlockingCollection<T> considering it is thread-safe?

Any suggestions?

 public class APPInfo
 {
        public String Machine { get; set; }
        public String IP { get; set; }
        public String Port { get; set; }
        public String App { get; set; }
        public ClientApplicationState Status { get; set; }
        public String Message { get; set; }
        public String TimeStamp { get; set; }
        public String CPUUse { get; set; }
        public String MemoryUse { get; set; }
        public String TotalCPUUse { get; set; }
        public String TotalMemoryUse { get; set; }
 }

public static ConcurrentQueue<APPInfo> AppQ = new ConcurrentQueue<APPInfo>();

 public static void Connect(Int16 Time)
 {    
       AppQ.Enqueue(new APPInfo { Machine = "One", IP = "127.0.0.1", Port = "23000", App = "TestServer1", Status = ClientApplicationState.OK, TimeStamp = DateTime.Now.ToString(), CPUUse = "80.0", MemoryUse = "81.0", TotalCPUUse = "86.0", TotalMemoryUse = "87.0" });

       AppQ.Enqueue(new APPInfo { Machine = "One", IP = "127.0.0.1", Port = "23001", App = "TestServer2", Status = ClientApplicationState.ERROR, TimeStamp = DateTime.Now.ToString(), CPUUse = "82.0", MemoryUse = "83.0", TotalCPUUse = "88.0", TotalMemoryUse = "89.0" });

       AppQ.Enqueue(new APPInfo { Machine = "Two", IP = "127.0.0.2", Port = "23002", App = "TestServer3", Status = ClientApplicationState.WARNING, TimeStamp = DateTime.Now.ToString(), CPUUse = "84.0", MemoryUse = "85.0", TotalCPUUse = "90.0", TotalMemoryUse = "91.0" });        
 }

 private void CheckQueue()
 {
     AppIP.Connect(50);
     APPInfo first = new APPInfo();         

     if (AppIP.AppQ.Count > 0)
     {
         AppIP.AppQ.TryDequeue(out first);

        MessageBox.Show(first.App, first.IP, first.Port, first.Status.ToString(), first.Message, first.TimeStamp, first.CPUUse, first.MemoryUse, first.Machine, first.TotalCPUUse, first.TotalMemoryUse + "\n");
     }
     else
     {
          MessageBox.Show("There is nothing in the queue to process.", "Important Note", MessageBoxButtons.OK, MessageBoxIcon.Error, MessageBoxDefaultButton.Button1);
     }
 }

miscellaneous: Can people post comments on where I may have gone wrong instead of just down voting a post and not giving reason

You are probably better off using something like Rx or at least, as you already mentioned, a blocking collection. — Num Lock, Jul 13 '17 at 09:06
@NumLock I've been searching relentlessly but I can't find any examples related to Rx. Can you point me in the right direction? I have never worked with it before. — Harold_Finch, Jul 13 '17 at 10:11
He is probably better off creating a wrapper around the ConcurrentQueue, adding Enqueue /Dequeue methods. Then either trigger an event when something is enqueued to do the processing, or directly calling a routine that loops until the queue is empty. — David C Fuchs, Oct 04 '19 at 21:46

Casperah · Answer 1 · 2017-07-13T11:35:27.573

1

In order to check queue once in a while you need to setup a timer:

 CheckTimer = new System.Threading.Timer(CheckQueue, null, TimeSpan.FromMilliseconds(1000), TimeSpan.FromMilliseconds(1000));

You should create the timer when you are initializing your service.

In your CheckQueue method you will need a loop to handle all the data in the queue.

private void CheckQueue(object dummy)
{
    // The dummy is null, its there because it is a Timer event.
    AppIP.Connect(50);

    AppInfo appInfo;
    while(AppQ.TryDequeue(out appInfo))
    {
        // Process the appInfo
    }
}

Note that the timer from System.Threading will run in different threads and the processing of the next event will happen even if the current event is still running!

edited Jul 13 '17 at 11:35

answered Jul 13 '17 at 09:35

Casperah

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Where do you use the `CheckTimer` ? – Harold_Finch Jul 13 '17 at 10:12
Also, what does the parameterized object do? Your answer is quite vague hey. Please see if you can update it maybe? @Casperah – Harold_Finch Jul 13 '17 at 10:24
I have added some comments to answer your questions, but what is wrong with the answer, why the -1? – Casperah Jul 13 '17 at 11:38
Before you TryDequeue, where do you check if there are actual items in the queue? @Casperah – Harold_Finch Jul 13 '17 at 11:40
According to the docummentation TryDequeue will return true if anything on the queue and false if the queue is empty https://msdn.microsoft.com/en-us/library/dd287208(v=vs.110).aspx – Casperah Jul 13 '17 at 11:53

Cycle through ConcurrentQueue indefinitely using either Timer/Stopwatch based event

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