question: private long indexOf ( final BTree ndx , final byte [ ] key ) { if ( log . isTraceEnabled ( ) ) { log . trace ( BytesUtil . toString ( key ) ) ; } final long indexOfKey = ndx . indexOf ( key ) ; if ( log . isTraceEnabled ( ) ) { log . trace ( "result of indexOf(key): " + indexOfKey ) ; } final long index ; if ( indexOfKey >= 0 ) { index = indexOfKey ; } else { index = - ( indexOfKey + 1 ) ; } if ( log . isTraceEnabled ( ) ) { log . trace ( "index: " + index ) ; } return index ; }
target:  Use the index to find the index of the tuple for the specified key (or the index of the next real tuple after the specified key).