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From: Craeg S. <cs...@ar...> - 2003-06-11 06:07:01
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>I would vote for this: > > class IXPathProcessor(Interface): > > def compile(expression): > "return compiled expression as IXPathExpression" > > class IXPathExpression(Interface): > > def evaluateString(xmlString, xmlURL, xpath): > "return result of xpath evaluation as string" > # doesn't have to be pretty printed > > def evaluateDOM(xmlNode, xmlURL, xpath): > "return a list of DOM nodes matching xpath" OK Thats done. > a compiletime notion of whether a particular > > processor supports feature X ... I guess we just say > > if IXPathProcessor.isImplementedBy(processor): > > # try it... > > Well, since we're going into the guts of ProcessorChooser anyway, I vote > for turning ProcessorChooser into ProcessorRegistry (doesn't have to be > renamed, although I would favour it), which would work similar to my > GeneratorRegistry. > It just provides a facility to register processor and query them > according to certain implementation features. I think we should not > query for strings like 'xslt', 'xpath', 'dtd', but for interfaces > (IXSLTProcessor, IXPathProcessor, etc.). That way we solve your issue a) > right at its root and b) becomes obsolent, because processors register > themselves (like my object Generators). I have refactored ProcessorChooser heavily and renamed it to ProcessorRegistry. However, I am unable to make it a mirror image of GeneratorRegistry. The reason is that it does lazy loading. Worse, even. It can *never* hold an instance of a processor, because then it would make ZSyncing across processors impossible. So making Processors register themselves once at runtime won't work. So my refactorings don't end up changing much. Basically I cleaned up the interface and made it more orthogonal, and changed to using compile() and exec() to eliminate the explicit calls to specific processors. In the end, however, I wonder if its really more readable or maintainable. If you get a chance, could you take a glance at the attached code? I think it might be on the borderline of being over-engineered... Thanks, --Craeg > > Thoughts? > > Philipp > > |
