CODEWITHSUNDEEP
javamultithreading
AL̲̳I
AL̲̳I

Reputation: 2461

Multiple threads to comunicate with multiple sensors

I am new to threads. I want to communicate with multiple sensors at one time after every minute continuously 24/7.

Senario: I have a method to talk to the sensors which takes 3 arguments

public String perform(String command, String ip, String port)
{
  //talk to the sensor and then 
  returns reply;
}

I have a database that contains the details of the sensor.

What I'm doing right now

while(true)
{
  //get sensors from database

   //run perform method for all instruments
   for(int i=0;i<sensors.length-1;i++)
   {
    //call perform method and save the reply
   }
   Thread.sleep('one minute');
}

Problem: The problem is if I have 100 sensors and each sensor takes 1 second to reply then after that I will be waiting for 1 minute, in this case I may lose some information. And to be honest sometime It takes more than a second to respond.

What I want to do is, get the information from the database for all the sensors then create one thread for each sensor. Then run all the threads at one time which will return me some information. After that wait for one minute then do it again.

Any help is appreciated.

Thanks

Upvotes: 0

Views: 497

Answers (2)

cyber-monk
cyber-monk

Reputation: 5570

Personally I would take a different approach. I would have the server always listening via a RESTful API and then have the sensors POST their state every minute (or other interval you decide). This way the server and the sensors don't need to be within the same JVM and IMHO is more scalable. Also, this way any sensor can also query for the state of any other sensor via another RESTful API on the server.

Additionally the server can start a thread to handle each POST and if one sensor is taking very long, the others are not blocked.

Upvotes: 0

Brian Agnew
Brian Agnew

Reputation: 272347

Have you looked at the ScheduledThreadPoolExecutor ?

A simple usage would be to create a Callable for each of your sensors, and configure the thread pool to contain as many threads as you have sensors. Then submit each Callable, specifying an appropriate schedule.

Note that this approach doesn't guarantee particularly accurate timings (Java's not by any means a real-time platform). The other issue is that creating a lot of threads can be relatively memory-hungry (IIRC the standard heap allocation per thread is 512k, but it's configurable) and this approach wouldn't scale if you had 1000s of sensors.

Upvotes: 2

Related Questions