package javathreads.examples.ch15;

public class LoopHandler implements Runnable {
    protected class LoopRange {
        public int start, end;
    }
    protected Thread lookupThreads[];
    protected int startLoop, endLoop, curLoop, numThreads;

    public LoopHandler(int start, int end, int threads) {
        startLoop = curLoop = start;
        endLoop = end;
        numThreads = threads;
        lookupThreads = new Thread[numThreads];
    }

    protected synchronized LoopRange loopGetRange() {
        if (curLoop >= endLoop)
            return null;
        LoopRange ret = new LoopRange();
        ret.start = curLoop;
        curLoop += (endLoop-startLoop)/numThreads+1;
        ret.end = (curLoop<endLoop) ? curLoop : endLoop;
        return ret;
    }

    public void loopDoRange(int start, int end) {
    }

    public void loopProcess() {
        for (int i = 0; i < numThreads; i++) {
            lookupThreads[i] = new Thread(this);
            lookupThreads[i].start();
        }
        for (int i = 0; i < numThreads; i++) {
            try {
                lookupThreads[i].join();
		lookupThreads[i] = null;
            } catch (InterruptedException iex) {}
        }
    }
 
    public void run() {
        LoopRange str;
        while ((str = loopGetRange()) != null) {
            loopDoRange(str.start, str.end);
        }
    }
}