GXL Ric Holt , Andy Schürr, Susan Elliott Sim, Andreas Winter
Graph eXchange Language


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     GXL 1.1

GXL 1.1 
Document Type Definition (GXL Module)

(alpha release, December 6, 2002)

[attribute-module]  [graph-module]

uncommented document type definition: gxl-1.1.dtdgxl-1.1_attribute.dtdgxl-1.1_graph.dtd

copyright by

  Andy Schuerr
    Real-Time Systems Lab
    Darmstadt University of Technology
    Merckstr. 25, D-64283 Darmstadt, Germany
    andy.schuerr@es.tu-darmstadt.de

  Susan Elliott Sim
    School of Information and Computer Science
    444 Computer Science Bldg.
    University of California, Irvine
    ses@ics.uci.edu

  Ric Holt
    Department of Computer Science
    University of Waterloo
    Waterloo N2L 3G1, Canada
    holt@plg.uwaterloo.ca

  Andreas Winter
    Institute for Software Technology
    University of Koblenz-Landau
    Universitaetsstrasse 1, D-56070 Koblenz, Germany
    winter@uni-koblenz.de

GXL has been developed to be an open standard.  No licensing or other legal arrangements are required  for its use, whether commercial and non-commercial.  The specification of GXL is copyright by its authors, to allow control of its evolution. The specification can be reproduced and used without charge, but with explicit acknowledgement of its authors.

This DTD is a proposal for GXL 1.1. The changes that were made are based on several change-request that were sent by GXL-users until August 31, 2002. Most of theese proposals have been realised, some partially and some have not, e.g. because GXL already provides the requested functionality. A complete description of what has changed and why will be available next spring as part of my (Oliver Heinen) Studienarbeit. For now, all changes in the DTD are marked with a blue background. Please send your comments to the GXL-mailinglist so that they can be discussed by all members.

-->

<!ENTITY % gxl-1.1_graph SYSTEM "gxl-1.1_graph.dtd">
%gxl-1.1_graph;
<!ENTITY % gxl-1.1_attribute SYSTEM "gxl-1.1_attribute.dtd">
%gxl-1.1_attribute;

<!--
The GXL 1.1-DTD is modularized, the graph- and the attribute-module are included into the GXL-module.
By changing the vaules of the entities, the GXL-modules might be replaced by other modules.
Based upon CR #2 (Packages).
-->

<!-- Extensions -->

<!ENTITY % gxl-extension     "" >
<!ENTITY % gxl-attr-extension     "" >

<!-- gxl -->

<!ELEMENT gxl  (headergraph* %gxl-extension;) >

<!--
According to CR #8 (Header), there is the opportunity to store additional information about the graph in the new header-tag.
-->


<!ATTLIST gxl
    xmlns:xlink CDATA    #FIXED    "http://www.w3.org/1999/xlink"
    xmlns:gxl CDATA    #FIXED   "http://www.gupro.de/GXL/gxl-1.1.dtd"

<!--
The GXL-namespace is, as requested in CR #6 (Namespace), defined as "http://www.gupro.de/GXL/gxl-1.1.dtd".
-->

    %gxl-attr-extension;
>

<!--
The GXL-tag is used to delineate a GXL document, which may contain multiple graphs.  In particular, it is possible to keep an data (represented as a GXL graph), schema (represented as a GXL graph), meta schema (which is represented as a GXL graph), and so on in one document.

XML requires all identifiers used in one document (not in one graph) to be disjoint.  Consequently, identifiers must be unique across graphs in GXL documents containing multiple graphs. GXL forbids references between graph elements of different graphs in the same document except for type allocation and within locator attributes.

GXL uses XLink to refer to object possibly defined outside the current GXL document. This requires declaration of XLink namespace. The fixed xmlns:xlink attribute makes the prefix xlink available within the gxl element. The XLink attributes can now be used in GXL documents (including their definition in the DTD) as xlink:[attribute]

Further elements may be added to GXL documents by redefining %gxl-extension;. Further attributes of GXL documents can be added by redefining %gxl-attr-extension;.

-->

<!-- header -->

<!ELEMENT header (attr)* >
<!ATTLIST header
    generatorTool  CDATA    #IMPLIED 
    Author         CDATA    #IMPLIED 
    Date           CDATA    #IMPLIED 
>

<!--
According to CR #8 (Header), GXL may contain a header to store additional information of four predefined and various self-defined (attr*) types.
-->


outsorted elements:

<!-- type -->

<!ELEMENT type EMPTY>
<!ATTLIST type
    xlink:type  (simple)    #FIXED  "simple"
    xlink:href  CDATA       #REQUIRED
>

<!--
The type-element isn't necessary in GXL 1.1 anymore, the type-attributes of graph and the graph elements (node, edge and rel) have taken it's functionality. Graph's type-attribute contains the uri to the according schema-graph. The type-attributes of the graph-elements only contain the id of the according schema-element - the complete uri to this element can be derived through the graph's type-element.
-->


 

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July 17, 2002

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