Multi-Threading

Threads

A thread in a program is a task. All programs have a “main” thread which controls everything that happens, including separate threads. Separate threads run alongside the main thread, similar to multitasking.

In Java, threads are objects that can be created from the Thread class. To do so, you need to create a subclass of the Thread class.

Threads in Java require two things: a constructor and a run() method. The constructor initializes any fields you would need in the thread, and the run() method is what is run when the thread is started. A sample thread is shown below.

public class MyThread extends Thread // Create a subclass of Thread
{
    /* Any fields/variables */

    public MyThread(/* Any arguments... */) {
        /* Initialize fields */
    }

    public void run() {
        // What to do when the thread starts
    }
}

To start this thread, create an object/instance of your Thread subclass and call the start() method.

MyThread thread1 = new MyThread(/* Any arguments */);
thread1.start(); // Start the thread
// ... 
thread1.stop(); // Stop the thread

Processing has its own thread interface separate from Java. The official documentation from Processing can be found here. Processing threads only require you to reference the name of the method that should be run when the thread starts.

void what_to_run() {
    // What to run when the thread starts
}

void draw() {
    thread("what_to_run"); // Start the thread
}

Python has a multiprocessing module that has the same functionalities as threads. Documentation can be found here.

Here is a sample use of Python multiprocessing:

from multiprocessing import Process

def what_to_run("""Any arguments"""):
    # What to run when the process starts

myProcess = Process(target = what_to_run, args(""" Any arguments for the function call """))
myProcess.start()
myProcess.wait(5) # Wait (at most 5 seconds) for the process to finish. If it doesn't finish, raise an exception
myProcess.terminate() # Force stop of the process using SIGTERM

Sample code can be found in the resource package.