question: final public Task schedule ( long msec ) { if ( stop ) { onStop ( fast ) ; } else { if ( executor == null ) return this ; synchronized ( lock ) { if ( runningQueue . contains ( this ) ) { if ( log . isDebugEnabled ( ) ) log . warn ( "the task is running, ignored: " + getName ( ) ) ; return this ; } if ( pendingQueue . contains ( this ) ) { if ( sf != null ) { sf . cancel ( false ) ; } log . warn ( "reschedule the task:" + getName ( ) ) ; } t . set ( System . currentTimeMillis ( ) + msec ) ; sf = executor . schedule ( this , msec , TimeUnit . MILLISECONDS ) ; pendingQueue . add ( this ) ; } } return this ; }
target:  Schedule the worker task.