[SAGA-RG] Semantics of the ns_entry constructor

[Andre Merzky]

You are right: open should be able to open entries and
directories (which *are* entries).  open_dir should work
only for directories.  Same holds then indeed for the entry
and dir constructors.

Thanks, Andre.


Quoting [Mathijs den Burger] (Aug 11 2009):
> From: Mathijs den Burger <mathijs at cs.vu.nl>
> To: saga-rg at ogf.org
> Date: Tue, 11 Aug 2009 17:55:14 +0200
> Subject: [SAGA-RG] Semantics of the ns_entry constructor
> 
> 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.
> 
> Either way, the spec seems to contain an inconsistency...
> Or am I missing something?
> 
> Mathijs
-- 
Nothing is ever easy.