Question

I’m having a-bit of trouble with threads in java. Basically Im creating an array of threads and starting them. the point of the program is to simulate a race, total the time for each competitor ( i.e. each thread ) and pick the winner.

The competitor moves one space, waits ( i.e. thread sleeps for a random period of time between 5 and 6 seconds ) and then continues. The threads don’t complete in the order that they started as expected.

Now for the problem. I can get the total time it takes for a thread to complete; what I want is to store all the times from the threads into a single array and be able to calculate the fastest time.

To do this should I place the array in the main.class file? Would I be right in assuming so because if it was placed in the Thread class it wouldn’t work. Or should I create a third class?

I’m alittle confused :/

Answer 1

It’s fine to declare it in the method where you invoke the threads, with a few notes:

• each thread should know its index in the array. Perhaps you should pass this in constructor
• then you have three options for filling the array
  • the array should be final, so that it can be used within anonymous classes
  • the array can be passed to each thread
  • the threads should notify a listener when they’re done, which in turn will increment an array.
• consider using Java 1.5 Executors framework for submitting Runnables, rather than working directly with threads.