Subject: Re: [xsl] Confusing namespaces and xslt From: Paul <pflists@xxxxxxxxx> Date: Tue, 30 Sep 2008 10:28:47 -0400 |
Thanks! That is very helpful. On Mon, Sep 29, 2008 at 5:57 PM, Evan Lenz <evan@xxxxxxxxxxxx> wrote: > I like to be as surgical as possible in my incremental transforms, > especially when I've got a lot of things to update. In this case, I might > use different modes, such as "content" and "append", as shown below: > > <xsl:stylesheet version="1.0" > xmlns:xsl="http://www.w3.org/1999/XSL/Transform" > xmlns:client="http://somecompany.com/box/client" > xmlns:box="http://somecompany.com/box" > exclude-result-prefixes="client"> > > <!-- BUSINESS LOGIC: --> > <!-- Set the value for all <box:rotation-time> elements --> > <xsl:template mode="content" > match="box:rotation-time">newvalue</xsl:template> > > <!-- Append a <box:work-manager> element to the end of <work-managers> > content --> > <xsl:template mode="append" match="client:work-managers"> > <box:work-manager> > <!-- etc. --> > </box:work-manager> > </xsl:template> > > > <!-- GENERIC UTILITY CODE: --> > <!-- Identity transform for attributes, elements, comments, text, and PIs > --> > <xsl:template match="@* | node()"> > <xsl:copy> > <!-- Everything here (inside <xsl:copy>) only applies to elements --> > <xsl:apply-templates select="@*"/> > <xsl:apply-templates mode="content" select="."/> > <xsl:apply-templates mode="append" select="."/> > </xsl:copy> > </xsl:template> > > <!-- By default, just process the existing content --> > <xsl:template mode="content" match="*"> > <xsl:apply-templates/> > </xsl:template> > > <!-- By default, don't append anything --> > <xsl:template mode="append" match="*"/> > > </xsl:stylesheet> > > In other cases, I've also used "insert" (insert before existing content), > "before" (insert before the element itself), "after" (insert after the > element), and "att-value" (for updating just the attribute value, without > having to explicitly create a new attribute using <xsl:attribute> every > time). > > Having such surgical precision can be very satisfying, but I don't usually > bother if there are only one or two things to update (as in this example). > But I thought I'd throw the idea out there anyway, in case you have lots of > things to update or you anticipate adding more update rules. > > Evan > > > Wendell Piez wrote: >> >> Paul, >> >> At 03:44 PM 9/29/2008, you wrote: >>> >>> What would be the best way to actually take the input xml transform it >>> into a new xml and just change a value or add a new element? >> >> The best approach is to adapt the "identity transform", amending it with a >> bit of extra logic to effect the changes you want. >> >> This is a well-documented approach, once you know the keywords. As you >> might imagine, an identity transform is one in which the output replicates >> the input. Strictly speaking, what you are trying to write might be called a >> "near-identity transform" -- this might be as simple as adding a template. >> >>> Would it be best to do a template match on "/" and do a for-each on >>> each element and then test each element to see if it was the one I >>> wanted to change? >> >> No. It would be best to use template matching, as the standard identity >> transform does. Its operation is fairly simple and straightforward, albeit >> obscure if you don't know how XSLT templates work. But by the same token, >> it's an excellent lesson in templates, which is indispensable for anyone >> working with XSLT, and something you're much better off getting sooner >> rather than later. >> >> Use your favorite search engine to find writeups and you should be set. >> Ask back here if what you find isn't enough. >> >>> Would it be better to set up specify template match statements for >>> each of the top-level elements and output the xml from the input >>> document except in the case where I need to change it? >> >> Kind of ... the identity template (the heart of the logic) simply copies >> input to output. Then, yes, you add templates to catch the cases where you >> want to do something differently, like add or change or remove something. I >> say "kind of" since the template matches all nodes, not just nodes at the >> top level. >> >> Cheers, >> Wendell >> >> >> ====================================================================== >> Wendell Piez mailto:wapiez@xxxxxxxxxxxxxxxx >> Mulberry Technologies, Inc. http://www.mulberrytech.com >> 17 West Jefferson Street Direct Phone: 301/315-9635 >> Suite 207 Phone: 301/315-9631 >> Rockville, MD 20850 Fax: 301/315-8285 >> ---------------------------------------------------------------------- >> Mulberry Technologies: A Consultancy Specializing in SGML and XML >> ======================================================================
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