compares object1 and object2 using comparator . if object1 or object2 is null/nskeyvaluecoding . nullvalue it will sort before the other object . concode_field_sep PlaceHolder placeHolder concode_field_sep int compareWithNullsLast
int function ( NSComparator arg0 , Object arg1 , Object arg2 ) { if ( arg1 == null || arg1 == NSKeyValueCoding . NullValue ) { return ( arg2 == null || arg2 == NSKeyValueCoding . NullValue ) ? 0 : - 1 ; } if ( arg2 == null || arg2 == NSKeyValueCoding . NullValue ) { return 1 ; } return arg0 . compare ( arg1 , arg2 ) ; }