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RE: Multiple and circular import/include

From: Jack Lindsey <tuquenukem@hotmail.com>
Date: Thu, 03 Mar 2005 22:37:14 -0500
Message-ID: <BAY102-F30D3B4CE8C87B1F53041FBD75C0@phx.gbl>
To: bill.michell@bbc.co.uk, vivekorama@gmail.com, rschloss@us.ibm.com
Cc: xmlschema-dev@w3.org

I absolutely agree.  However, such recursive element references that span 
files with redundant xs:include/import statements can crash JAXB, as a 
development team politely informed me.  Then I got a taste of my own 
medicine when Spy 2005 SP1 did the same to me.  I just upgraded but to keep 
my developers happy, I am trying a re-modularization of a large schema.   
After all, the customer is always right!

Cheers Jack

>From: "Bill Michell" <bill.michell@bbc.co.uk>
>To: "vivek agarwal" <vivekorama@gmail.com>,        "Bob Schloss" 
><rschloss@us.ibm.com>
>CC: <xmlschema-dev@w3.org>
>Subject: RE: Multiple and circular import/include
>Date: Thu, 3 Mar 2005 09:32:50 -0000
>
>
>I find them really useful...
>
>I have a generic "asset" that can have many types of extension - but any 
>instance of that asset need to be able to contain other assets - either 
>references, or completely embedded inline.
>
>The core document contains the basic asset definition but the extensions 
>each live in their own schema - that needs a reference to the core document 
>- which in turn needs a reference to the current collection of extension 
>schemae...
>
>In other words elements can be nested recursively so the schema documents 
>need to be able to express that nesting.
>
>
>
>--
>Bill Michell
>Development Team Leader, Broadcast Platforms, BBC News Interactive.
>
>
>
>-----Original Message-----
>From: xmlschema-dev-request@w3.org [mailto:xmlschema-dev-request@w3.org] On 
>Behalf Of vivek agarwal
>Sent: Wednesday, March 02, 2005 9:03 PM
>To: Bob Schloss
>Cc: xmlschema-dev@w3.org
>Subject: Re: Multiple and circular import/include
>
>
>Thanks Bob!
>But, I still don't understand why the spec allows circular references!? Is 
>there a reason? or is it just like that?
>
>Thanks,
>Vivek.
>
>
>
>On Tue, 1 Mar 2005 15:17:04 -0500, Bob Schloss <rschloss@us.ibm.com> wrote:
> >
> >
> > Vivek,
> >
> >       It is not an error to include the same schema document as the
> > target of multiple <include> or <import> directives.
> >
> >       Circular <include> or <import> directives are permitted.
> >
> >       This is my mental model:
> >
> > 1. The processor fetches your top-level schema document, and then
> > keeps fetching any other schemas which are referenced through
> > directives, transitively, but whenever it sees a directive targetting
> > something it has already fetched, it doesn't fetch it again.  At the
> > end of this process, the "actual schema" to be used for processing now
> > exists in memory, having been merged from 1...n individual documents
> > having the XML representation of XML Schema.
> >
> > 2. Then the processor starts doing whatever it plans to do (validation
> > of instance documents during parsing, generating Data Binding code,
> > generating UI forms, or whatever).
> >
> >       Because of subtleties associated with <redefine>, for the sanity
> > of anyone who may have to maintain what you design, I would try to
> > avoid circular redefines.
> >
> >             Good Luck,
> >             Bob
> >
> > Scalable XML Infrastructure
> > IBM Thomas J Watson Research Center
> > Yorktown Heights, New York, USA
> > http://www.research.ibm.com/XML
> >
> >              vivek agarwal
> >              <vivekorama@gmail
> >              .com>                                                      
>To
> >              Sent by:                  xmlschema-dev@w3.org
> >              xmlschema-dev-req                                          
>cc
> >              uest@w3.org
> >                                                                    
>Subject
> >                                        Multiple and circular
> >              03/01/2005 01:41          import/include
> >              AM
> >
> >              Please respond to
> >                vivek agarwal
> >
> >
> > Hi,
> >
> > I have a question on multiple and circular import/include each, if
> > somebody could help.
> >
> > Is it an error to import/include a schema more than once?
> > A import/includes B1 and B2.
> > Both B1, and B2, import/includes C.
> > What is the expected behaviour of the processor in such a case?
> >
> > Are circular import/includes allowed?
> > A import/includes B, and B import/includes A?
> > What is the expected behaviour of the processor in such a case?
> >
> > Thanks,
> > Vivek.
> >
> >
>
>
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>
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Received on Friday, 4 March 2005 03:38:41 GMT

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