Generic XML displayer
---------------------
As part of a project of network simulator, I have begun
a generic XML displayer with JGraph (http://jgraph.sf.net).

I made a class DOMGraphModel: wrapper of one or more
DOM XML Node and its sub-tree from the same or
different DOM Document as a JGraph GraphModel : see
source code here:
http://jmvanel.free.fr/graph/
Compile it with jgraphpad.jar
Try it with :
java com.jgraph.dom.app.SampleEditorApp any.xml
(you can use for instance the build.xml of JGraph)

There are "collapse sub-tree" and reverse contextual
commands, and the embryo of a command history with
a button "Undo last Edit".

There is currently a home-made Layout, that allocates to each node an
horizontal space proportional to its total number of children.

An XPath query does a JGraph selection of the DOM NodeList result.

* tested Sujiayama algorithm : it works, but you need to select the sub-tree first.
* open URL in general menu (can give a file name or an URL on command line or File Chooser)


There is another main():
com/jgraph/dom/pad/DOMJGraphPad

which is simply the inclusion of the DOMGraphModel in JGraphpad.
The user is able to add an XML Element by adding a vertex 
and an edge from it in the normal JGraphpad way. 
Currently the added element has name "node", and user has no choice;
"save as ... .pad_xml" works, but the labels are not saved.

DOM --> Graph mapping
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The default is to have 1 element --> 1 vertex. The attributes, text and other
XML nodes are not represented. The tooltip on vertices show the XML attributes
and the first text child, if any.

Mapping and view customization
------------------------------
* Custom Vertex JGraph Attributes
	see interface CustomVertexAttributes
* take in account a pruned XML tree in DOMTreeLayout
    * what to prune specified in :
      boolean GraphNodeFilter.pruneNode(Node n)
    *  there is another Filter for XML nodes. Contrary to pruneNode(), 
       a node can be excluded but its children not excluded ("shortcut"):
          public boolean acceptNode(Node n);

Future:
-------
There will be a new GUI for queries and transforms of several kinds: XPath,
XSLT, XQuery.

There will be a highlight of "legal" target ends when linking an edge,
hopefully using the XML Schema.

I plan to integrate a generic "classic" XML editor for the edition of leaf elements and
small sub-trees. It might be Gendoc (on sf.net).

I plan to show keyref associations in the XML document
as links (edges) in the graph.

Later I plan to do editing
according to an XML Schema .