two-phrase termination pattern

TerminableThread.java

public abstract class TerminableThread extends Thread {

    private volatile boolean stopRequested;
    private volatile boolean stopped;

    public boolean isStopRequested() {
        return stopRequested;
    }

    public boolean isStopped() {
        return stopped;
    }

    public void terminate() {
        if (stopRequested) {
            return ;
        }

        stopRequested = true;
        try {
            beforeTermination();
        } finally {
            if (isIdle()) {
                super.interrupt();
            }
        }
    }

    @Override
    public void interrupt() {
        terminate();
    }

    @Override
    public void run() {
        Throwable t = null;
        try {
            for (;;) {
                if (isStopRequested() && isIdle()) {
                    break;
                }

                doRun();
            }
        } catch (Throwable cause) {
            t = cause;
        } finally {
            afterTermination(t);
        }

        stopped = true;
    }

    protected void beforeTermination(){
        // NOOP
    }

    protected void afterTermination(Throwable t){
        // NOOP
    }

    protected abstract void doRun() throws Exception;
    protected abstract boolean isIdle();
}