[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Exceptions or not (Was: RE: ModSAX (SAX 1.1) Proposal)
Jarle Stabell wrote, > True. I love exceptions and find that they greatly > improves the robustness of applications, but the > reason I'm not convinced about whether it is good > to be forced to specify what will be thrown is that > this in many cases seem to require psychic powers of > the designer (or that the "real" exceptions must be > catched and converted into an "acceptable" one, which > looses information). What you need is (to coin a phrase) an 'exception tunnel'. For example, public class SAXExceptionTunnel extends SAXException { private Throwable itsThrowable; public SAXException(Throwable throwable) { itsThrowable = throwable; } public Throwable getThrowable() { return itsThrowable; } public void rethrow() throws Throwable { throw itsThrowable; } } You could use it like this, public class Foo { public void someMethod() throws SAXException { try { // do some stuff } catch(SomeWierdException ex) { throw new SAXExceptionTunnel(ex); } } } Foo someFoo = new Foo(); try { someFoo.someMethod(); } catch(SAXExceptionTunnel ex) { // deal with tunnelled exceptions here System.err.println(ex.getThrowable().getMessage()); ex.rethrow(); } catch(SAXException ex) { // deal with ordinary exceptions here } I've found this idiom extremely useful in many situations where I've wanted to register callback handlers without either imposing restrictions on them (ie. no IOExceptions allowed to leak out of the handler) or having to use ludicrously general throws clauses. Cheers, Miles -- Miles Sabin Cromwell Media Internet Systems Architect 5/6 Glenthorne Mews +44 (0)181 410 2230 London, W6 0LJ msabin@c... England 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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