private void doAddWorker() {
        if (idleWorkers.get() == 0) {
            synchronized (workers) {
            	if (workers.size() >= getMaximumPoolSize()) {
                    return;
                }
                if (workers.isEmpty() || (idleWorkers.get() == 0)) {
                	addWorkerUnsafe();
                }
            }
        }
    }
private void doAddWorker ( ) { if ( idleWorkers . get ( ) == 0 ) { synchronized ( workers ) { if ( workers . size ( ) >= getMaximumPoolSize ( ) ) { return ; } if ( workers . isEmpty ( ) || ( idleWorkers . get ( ) == 0 ) ) { addWorkerUnsafe ( ) ; } } } }
如果活动的线程数量=0则添加线程