public synchronized boolean flush() {
		if (!validState) {
			throw new InvalidStateException();
		}
		try {
			flushBuffer();
			return true;
		} catch (Exception e) {
			log.error("Exception in flush()", e);
		}
		return false;
	}
public synchronized boolean flush ( ) { if ( ! validState ) { throw new InvalidStateException ( ) ; } try { flushBuffer ( ) ; return true ; } catch ( Exception e ) { log . error ( "Exception in flush()" , e ) ; } return false ; }
Flush buffer to file

@return false if exception occur