question: public void addSample ( Sample stat ) { samples . add ( stat ) ; if ( samples . size ( ) == 1 ) { start = stat . start ; end = stat . end ; } this . ioBytes += stat . ioBytes ; this . jobMsgCnt += stat . jobMsgCnt ; this . msgCnt += stat . msgCnt ; this . msgBytes += stat . msgBytes ; this . start = Math . min ( this . start , stat . start ) ; this . end = Math . max ( this . end , stat . end ) ; }
target:  Adds a sample to the group.