creating multiple threads

[tomo black]

hi,
i'm hoping to generate a random number, check if it's even of not and pass odd/even as an arg to a newly created thread. but i dont quite understand how to do so( the thread part). i want to create dozens of threads.
can anyone help?

thanks tomo

[Stefan Krompass]

Hi,

you can pass arguments to threads via constructor. Just implement a class that implements interface Runnable (or extends class Thread) and pass whatever you like:

class MyThread implements Runnable {
  private isEven;
 
  MyThread(boolean isEven) {
    this.isEven = isEven;
  }
 
  public void run() {
    ...
  }
}

Stefan

[tomo black]

hi stefan, thanks for your reply.
i was creating the multiple threads like so but i read that you shouldn't use Runnable for multiple threads. This wont compile properly (cant recognise NEW symbol) and i'm not sure how to fix it.


myThread implements Runnable;
int x;
while(true)
{
x= randomNo();
if(x%2==0)
new myThread(true);//even
else
new myThread(false);//odd
}

[Henry Wong]

Originally posted by tomo black:
hi stefan, thanks for your reply.
i was creating the multiple threads like so but i read that you shouldn't use Runnable for multiple threads. This wont compile properly (cant recognise NEW symbol) and i'm not sure how to fix it.

Tomo, we can't really help you with compile problems, when you only show us pseudo code. Please give us the code you tried to compile.

Henry

[Stan James]

if "new myThread(true)" is real code, you need to create a Thread to use your runnable and start it. The line might look like:

new Thread( new MyRunnable( true ) ).start();
// or
Thread t1 = new Thread( new MyRunnable( true ) );
t1.start(); // you get to keep a reference to the thread

Just to sharpen up your eye, do you see a way to pass true or false to your constructor without setting a variable and doing an if test? Deleting code is my favorite part of programming so reducing four lines to one would make me smile all day.

[Jeroen Wenting]

Originally posted by tomo black:
hi stefan, thanks for your reply.
i was creating the multiple threads like so but i read that you shouldn't use Runnable for multiple threads. This wont compile properly (cant recognise NEW symbol) and i'm not sure how to fix it.

That's false advise. Whether you use Runnable or not depends on design decisions, not the number of instances you're going to create.
Just be sure to create (unless you have specific requirements) a separate instance of your Runnable class for each Thread you create and you should be fine.