question: public boolean testAndSetRecvSequencenumber ( int newValue ) { if ( recvSequenceNumber == null ) { recvSequenceNumber = new AtomicInteger ( newValue ) ; return true ; } int oldValue = recvSequenceNumber . get ( ) ; boolean wrapAround = ( oldValue & 0x00000000ffffffff ) >= 4294966271L ; boolean exactMatch = oldValue + 1 == newValue ; boolean wrapMatch = wrapAround & ( newValue < 1024 ) ; boolean match = exactMatch | wrapMatch ; if ( match ) recvSequenceNumber . set ( newValue ) ; return match ; }
target:  Tests whether value matches expected sequence number and sets a new value. If value has never been set before the test passes and new value is set. Test passes if the value is one larger than previous value or if previous value is 4294966271 or larger.