displayname property in jcr-server

[Brian Moseley <bc...@maz.org>]

jcr-server is a bit problematic in the way it treats the display name of 
a webdav resource. specifically it forces the display name to be the 
same as the name of the resource itself, rather than an arbitrary 
textual description of the resource. this is an acceptable default value 
for a resource's display name, but a webdav client should be able to 
change the display name at any point after creation of the resource.

rfc 2518 says:

13.2 displayname Property

    Name:       displayname
    Namespace:  DAV:
    Purpose:    Provides a name for the resource that is suitable for
    presentation to a user.
    Description: The displayname property should be defined on all DAV
    compliant resources.  If present, the property contains a description
    of the resource that is suitable for presentation to a user.

    <!ELEMENT displayname (#PCDATA) >

i realize that the goal of the simple webdav server is to support 
nt:collection and nt:file, which don't allow extra properties. that's 
fine; i have defined my own dav:collection and dav:resource node types 
on which i can add a dav:displayname property. i can then override 
DavResourceImpl.getDisplayName() to return the value of that property.

the problem is that DavResourceImpl.getDisplayName() as already 
implemented has a couple of other purposes - calculating the resource 
name for a node that is about to be created and returning the resource 
name from an existing node.

furthermore, both resource and display names could potentially contain 
characters that are illegal in jcr names. we've talked in the past about 
encoding these strings in order to use them as jcr names. this encoding 
would be necessary for the resource name (which is used as the node's 
name) but not for the display name (which would be persisted as a 
property value).

i propose the following DavResourceImpl methods:

   getResourceName() - returns the (unencoded) name of the resource, 
which is either the name of the resource's node (if the resource exists) 
or the final segment of the resource's uri path

   getDisplayName() - returns the value of the resource's 
DAV:displayname property (if both the resource and property exist) or 
the string returned from getResourceName

DavResourceImpl could simply always `return getResourceName()' as its 
implementation of getDisplayName(). subclasses would be free to override 
it to retrieve the display name from a jcr property.

DavResourceImpl would also take care of encoding the resource name 
before creating the new node and decoding the resource name before 
returning it from getResourceName().

thoughts?