question: public void processPrevTimeLine ( String messageID , IAnalyzedInterval contextElement , StatisticsChart sc , Set < Long > timeLineSet ) throws AdeInternalException { final TreeSet < Long > prevTimeLine = m_prevIntervalTimelineMap . get ( messageID ) ; if ( prevTimeLine == null ) { m_mainStat = MainStatVal . NEW ; m_deltasInSeconds . add ( ( m_firstMsgTime - contextElement . getIntervalStartTime ( ) ) / DateTimeUtils . MILLIS_IN_SECOND ) ; } else { final Long prevLastTime = prevTimeLine . lower ( m_firstMsgTime ) ; if ( prevLastTime != null ) { m_gc . setTimeInMillis ( prevLastTime ) ; sc . setStat ( "LastTime" , String . valueOf ( m_dataTypeFactory . newXMLGregorianCalendar ( m_gc ) ) ) ; final long delta = ( m_firstMsgTime - prevLastTime ) / DateTimeUtils . MILLIS_IN_SECOND ; m_deltasInSeconds . add ( delta ) ; timeLineSet . add ( prevLastTime ) ; } } }
target:  Processes the previous time line of the current message ID. 