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Posted to dev@xmlbeans.apache.org by "David Jencks (JIRA)" <xm...@xml.apache.org> on 2006/12/01 09:29:25 UTC
[jira] Commented: (XMLBEANS-299) Support substitution groups when
the substitution is compiled in a different jar
[ http://issues.apache.org/jira/browse/XMLBEANS-299?page=comments#action_12454832 ]
David Jencks commented on XMLBEANS-299:
---------------------------------------
I asked about this on 7/2/2006 and Radu replied in more detail than above on 7/27/2006. In geronimo we have exactly this problem of needing to be able to extend elements with other elements that are not known at the time the "base" schema is compiled.
I worked around this in geronimo by:
-registering substitution group elements in each additional schema with my own code
-filtering validation errors by seeing if the alleged unknown element is in fact a member of the substitution group, using the registration info just mentioned
-processing all substitution group members by registering a handler for each possible element with a handler collection, and when the processing code reaches the subtitutable element it iterates through the handler collection giving each handler a chance. The handlers use XmlObject.selectChildrenForQNameSet to look for the elements they are interested in.
This works but is inconvenient.
I certainly don't understand xmlbeans as well as Radu but I thought it would be possible to have additional schemas, as they load, register the new substitution group element in the data structure that track the substitution group elements. I forgot where this data structure is, but I found it once :-).
I think anyone who wants to use this feature would be happy to load all the schemas they wanted to use before processing any documents, and perhaps explicitly construct a SchemaTypeLoader or SchemaTypeSystem and probably call specific methods to register the extension schemas to get this to work.
So, I don't see why any code needs to assume anything is unknown by the time a document is parsed.
> Support substitution groups when the substitution is compiled in a different jar
> --------------------------------------------------------------------------------
>
> Key: XMLBEANS-299
> URL: http://issues.apache.org/jira/browse/XMLBEANS-299
> Project: XMLBeans
> Issue Type: Improvement
> Components: Binding
> Affects Versions: Version 2.2, Version 2.2.1
> Reporter: Radu Preotiuc-Pietro
> Fix For: TBD
>
>
> XMLBeans doesn't currently support substitution groups where the head element is compiled in a jar and the substitutions are compiled at a later time in a different jar.
> Because XMLBeans doesn't have the opportunity to save in the serialized xsb information about substitution groups (since these do not exist at the time the xsb is created) then it is forced to assume that any element can be a substitution for anything else and the only way to reliably tell is to load the element declaration. But loading the element declaration each time two elements are compared for QName equality is going to be very expensive even if loaded from the cache. This whole thing will need to be enabled on-request and have its separate codepath.
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