On 31.1.13 13:08, Angela Schreiber wrote:
hi michael while looking at the TreeLocation implementation was wondering about NullLocation#getParent() as IMO it violates the API contract because it always returns the NULL-location. is there a particular reason for this? and wouldn't it be possible to return the original parent location through which this NULL location had originally be accessed? to me that would feel much more natural that having a location that all in a sudden is isolated from the hierarchy. what do you think?
The intention of NullLocation was to indicate that the path of navigation through which the NullLocation was obtained is invalid. But it is true that this somewhat contradicts the contract of getParent().
If we change this the way you propose, we need to keep track of a potential hierarchy of NullLocations. I.e. in the case someone calls getChild() on a NullLocation. If we do that, we should also change the contract of getPath() to not return null for NullLocations but rather the path of that location. Otherwise it is a bit funny that you can navigate from a location with a null path up the hierarchy to a location with a non null path.
Michael
regards angela+ /** + * @return {@code NULL} + */ + @Override + public TreeLocation getParent() { + return NULL; + }
