[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: ModSAX (SAX 1.1) Proposal
Hello, Why is interface ModHandler empty? Presumably, (an implementation of) ModParser is going to need to call methods on its handlers as it goes about its business . Will it somehow know that for ModHandlers which implement, say, namespace processing, that it should call a particular method (I won't even attempt to suggest what that method might be :-)? In java, empty "marker" interfaces appear: 1) for pieces of "silent" functionality like Cloneable and Serializable where a standard interface simply doesn't apply, or 2) where the variety of types of applications which will need to have a formalized contract with some piece of functionality is so broad that it is prohibitvely difficult to define the appropriate method signatures for that interface; extended interfaces are expected to proliferate (e.g., EventListener & friends). It seems to me that SAX is clearly not a case of 1), and while it may be a 2), it isn't obviously so. EventListener is nice in the regard that it makes explicit that "there exists a contract between things that propagate events and things that respond to them"; it doesn't fix that contract for us, but it sets the tone of interaction. "EventSources" of essentially any kind are provided a template of how to interact in a decoupled way with those interested in what they're up to. In the case of SAX, the "EventSource" doesn't vary all that much; in some form or another we're always dealing with an XML parser. Do we need such latitude in defining the interactions between the parser and external modules? I'm afraid that ModHandler's current (suggested) definition is too open-ended -- it may encourage interoperability problems. The key virtue (in my opinion) of SAX is that it allows me to plug an arbitrary parser into the front of my XML processor and I'm nearly guaranteed that if it's IBM's or J. Clark's or whomever's, it's going to work. A marker interface inside the parser seems to me to threaten this happy state of affairs... Regards, Tito. ps - I also "vote" with D. Park that "ModularParser/Handler" are nicer names than "ModParser/Handler"... otherwise developers may be confused that ModParsers are just Parsers that like vespas, bomber jackets and The Smiths... ;-> xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To (un)subscribe, mailto:majordomo@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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