WorkManager.java

package org.apache.cassandra.stress;

import java.util.concurrent.atomic.AtomicLong;

public interface WorkManager
{
    // -1 indicates consumer should terminate
    int takePermits(int count);

    // signal all consumers to terminate
    void stop();

    static final class FixedWorkManager implements WorkManager
    {

        final AtomicLong permits;

        public FixedWorkManager(long permits)
        {
            this.permits = new AtomicLong(permits);
        }

        @Override
        public int takePermits(int count)
        {
            while (true)
            {
                long cur = permits.get();
                if (cur == 0)
                    return -1;
                count = (int) Math.min(count, cur);
                long next = cur - count;
                if (permits.compareAndSet(cur, next))
                    return count;
            }
        }

        @Override
        public void stop()
        {
            permits.getAndSet(0);
        }
    }

    static final class ContinuousWorkManager implements WorkManager
    {

        volatile boolean stop = false;

        @Override
        public int takePermits(int count)
        {
            if (stop)
                return -1;
            return count;
        }

        @Override
        public void stop()
        {
            stop = true;
        }

    }
}