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From Benson Margulies <>
Subject Re: How many XML Schema libraries at ASF is too many XML Schema Libraries?
Date Sun, 05 Apr 2009 22:44:24 GMT

Historically, that might have been the case or the intention, but there's
nothing 'pull-y' about it today. If you feed it files, it builds dom and
walks dom. If you feed it dom, it just walks dom.

Now, I'm not an axis2 developer, I'm a cxf developer, but from inside the
code I just can't see how it would be a problem.


On Sun, Apr 5, 2009 at 6:22 PM, Lawrence Mandel <> wrote:

> Hi Benson,
> I may not be remembering correctly, but I thought that one of the reasons
> for developing XmlSchema in WS-COMMONS was to support a pull based model
> (Axiom). I completely agree that there should not be duplication of effort
> around these models at Apache. (Our collective time is better served solving
> other problems.) Do you foresee any issues (primarily with Axis2) with
> moving XmlSchema to a strictly DOM based model? Is this question even
> relevant?
> Thanks,
> Lawrence
>  From: Benson Margulies <> To:
> Cc: Daniel Kulp <>,
> Date: 04/05/2009 05:45 PM Subject: How many XML
> Schema libraries at ASF is too many XML Schema         Libraries? Sent by:
> ------------------------------
> Dear Xerces-J developers,
> At the moment, I'm the most active maintainer of Apache Xml Schema. This
> library, which lives inside the WS-COMMONS project, which lives inside the
> Web Services TLP, is a set of Java classes that form a data model for W3C
> XML Schema, together with code to walk DOM of schema documents and build the
> representation and visa versa.
> XmlSchema has no capability to validate a document against a schema.
> Typical applications, such as Apache CXF or Apache Axis, spend a fair amount
> of time converting back and forth between XmlSchema representation and the
> ordinary DOM for schema documents, if only to pass them into the
> SchemaFactory to tee up validation, or into some other library.
> While I haven't gone spelunking in the code of Xerces yet, the existence of
> the validation feature strikes me as strong circumstantial evidence the
> existence of some representation of schema.
> It strikes me that two Java class libraries for W3C XML Schema inside ASF
> is, prima facia, one too many. So, I'm sending this email to ask if the
> Xerces project has interest in working on exposing a documented API to the
> XML Schema data model.
> I was am more or less on the verge of putting a significant pulse of effort
> into modernization and performance enhancement of XmlSchema, and if the same
> effort could yield a more broadly useful result, I'd like to apply it there.
> I am imagining a scheme where the core representation *is dom*, using
> subclasses of DOM interfaces to supply convenience methods for safe and
> comprehensible access to the abstract data model. This could radically speed
> up code that needs to handle schema documents as DOM and also analyze and
> manipulate the abstract data model of the W3C Xml Schema. But, imagination
> aside, I think it would be good to focus energy on a shared solution.
> Regards,
> Benson Margulies

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