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From David Peterson <peter...@ee.usyd.edu.au>
Subject Re: Validating content sent to style="message" services
Date Wed, 15 Jan 2003 20:26:49 GMT

Hi Dave,

If your current method of calling toString() on the SOAP body is giving 
you the XML that you wish to validate (and, I assume, the XML is 
well-formed, not mal-formed), then I see no problem with using that 
approach. {Others may have a comment to add?}

I'm not quite sure why you'd use a "Transformer". This usually refers to 
XSLT (eXensible StyLesheet Transformations) - in which you construct a 
"Transformer" from an XSL stylesheet (really an output formatting 
template), and pump your XML source data through the Transformer to 
produce your (also XML) output file - according to the XSL 
transformation rules. Now, that said, I can't see how and where you'd 
use this to *obtain* your SOAP body XML, except for possibly 
constructing an "identity" transform (this is done by creating a new 
Transformer from an "empty" XSL transform (sometimes called the identity 
transform: a bit like the I in matrix theory - X*I = X) ), which may 
allow you to use the transformer technique to obtain a copy of the SOAP 
body XML. But to me, this seems like the long way around ... I think 
that your toString() method is winning on the basis of simplicity!

Once you have the XML body (via any technique) you push it into a 
validating parser. I believe this means you must use DOM parsing rather 
than SAX parsing, as from what I understand SAX parsers do not support 
validation. You should be able to use the JAXP (Java API for XML 
Processing) API (for parser independence). This will find a concrete 
parser implementation (such as Xerces.jar) and use it. Or, you could 
write code which uses Xerces directly (less advisable as then you have 
made your s/w dependent on a particular parser). A third option is to 
look at dom4j or JDOM if you think these libraries will make your 
parsing easier. Again, using these you add a dependency to your system.

HTH.

Dave





Irving, Dave wrote:

>Thanks for your help Dave,
>
>Using a handler would be a pretty nice way of doing this - I'll look further
>in to it.
>Im a complete newbie to AXIS though, so Im a bit confused as to how I get
>'back' to an XML source to parse again.
>It is a contained SOAPBody which I wish to validate, and I believe JAXP says
>I should use a Transformer to do this.... However, I notice that if I get
>hold of the body, a 'toString()' provides me with the original XML content
>of the body!!
>Is this an ok feature to use, or should I stick with a Transformer?
>
>Many thanks,
>
>Dave
>
>-----Original Message-----
>From: David Peterson [mailto:peterson@ee.usyd.edu.au]
>Sent: 15 January 2003 19:58
>To: axis-user@xml.apache.org
>Subject: Re: Validating content sent to style="message" services
>
>
>
>Hi Dave,
>
>Since no-one else seems to have had a crack at your question, I will.
>
>I believe you can achieve what you are looking for by using"SOAP 
>handlers", which as I understand them are akin to "servlet filters" 
>except for the SOAP/web-services rather than Java servlets. Basically my 
>idea would be to create a SOAP handler that is invoked before the JAXM 
>message is processed by the web service, and pass the message XML to a 
>validating (DOM) XML parser. Obviously the parser would also need to be 
>able to fetch the DOM that matches the message in order to perform the 
>validation.
>
>Hope this helps. Comments from others welcome.
>
>David Peterson
>
>
>Irving, Dave wrote:
>
>  
>
>>Hi,
>>
>>My service will be using the "message" style rather than the RPC style (not
>>by choice..., but there we go..).
>>One thing Im really interested in doing is having the XML body validated
>>before it is received by my service.
>>Is there any configuration option of Axis which can be used to have this
>>handled automatically, or do I need to manually validate the content in the
>>service or handler?
>>
>>Many thanks,
>>
>>Dave Irving
>>
>>
>>    
>>



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