[SAGA-RG] Semantics of the ns_entry constructor

[Ceriel Jacobs]

Mathijs den Burger wrote:
> Hi all,
> 
> The specification of the constructor of ns_entry confuses me a bit.
> What happens if the provided URL points to an existing directory?
> 
> At page 205, the SAGA spec says:
> - the default flags are ’None’ (0)
> - the constructor performs an open of the entry 
> - all notes to the respective open call (on namespace_directory) apply.
> 
> But at page 233, the first note of ns_directory.open() says:
> - a ’BadParameter’ exception is thrown if ’name’ points to a directory,
> or is an invalid entry name.
> 
> Together, these notes imply that the constructor of ns_entry should
> throw a 'BadParameter' exception if it gets a URL that points to a
> directory. The Java SAGA implementation of the Vrije Universiteit indeed
> checks this case explicitly. I'm not sure what the other implementations
> do.
> 
> However, if no ns_entry object can point to a directory, the method
> ns_entry.is_dir() will always return false and is therefore pointless.

No, it is not. An ns_directory is also an ns_entry, and it may (should)
redefine the is_dir() method. And an ns_entry object CAN point to a
directory, but in that case it is an ns_directory object.

> Either way, the spec seems to contain an inconsistency...
> Or am I missing something?

I don't see the inconsistency. Am I missing something :-?

Ceriel