* the time in seconds allowed for the pool to shutdown nicely.
* After this the pool is forced to shutdown.
*/
public DefaultBackgroundExecutor(int schedulePoolSize, int corePoolSize, long keepAliveSecs,int shutdownWaitSeconds, String namePrefix) {
this.pool = new DaemonThreadPool(corePoolSize, keepAliveSecs, shutdownWaitSeconds, namePrefix);
this.schedulePool = new DaemonScheduleThreadPool(schedulePoolSize, shutdownWaitSeconds, namePrefix+"-periodic-");
}