import java.util.ArrayList;

/**
 * This program creates three Grunt objects, starts them running in separate threads, 
 * and then does the digital equivalent of twiddling its thumbs while it waits for them
 * to complete.  (Note that the Grunt threads in this case never complete, so the 
 * program runs forever.)
 * 
 * @author richards
 */
public class RunGrunts {
    /**
     * The standard Java main method.  Takes an array of command-line arguments, but
     * they're not used for anything in this example.
     * @param args  Ignored by main.
     */
    public static void main(String[] args)
    {
        ArrayList<String> output = new ArrayList<String>();
        
        // Make some grunt objects.  Pass constructor different ID and interval values.

        Grunt a = new Grunt(1, 10, output);
        Grunt b = new Grunt(2, 37, output);
        Grunt c = new Grunt(3, 137, output);

        // Each Grunt has the potential to execute "simultaneously" with main
        // and its Grunt siblings, but they don't actually do so until we 
        // wrap a Thread object around them and start the Thread running.
        // In some cases you really want to keep a reference to each Thread
        // object, but after starting the threads I don't need to access them
        // again here  so I just invoke start() on anonymous Thread objects.

        (new Thread(a)).start();
        (new Thread(b)).start();
        (new Thread(c)).start();

        // Stay alive, doing nothing, while the threads do their thing.  This is
        // a terrible way to wait, as it devours lots of CPU time, but is a simple
        // way to make the point...

        int size = output.size();
        System.out.println("Initial list size is "+size);
        while(true)
        {
            if (output.size() != size) {
                // Work our way through any new additions and print them
                for(; size<output.size(); size++) {
                    System.out.println("New addition: "+output.get(size));
                }
            }

        }
    }
}