[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: SAX2 Namespace Support
Brett McLaughlin wrote: > > David Brownell wrote: > > > > David Megginson wrote: > > > > > > In principle (the principle of least surprise), it's very bad > > > behaviour for two objects to be == in C++ or equals() in Java if any > > > of their publicly-accessible fields differ. Think of sets, for > > > example. > > > > Actually, it's quite common for nontrivial objects that equals() only > > involve a subset of the visible properties. It's probably even typical > > in applications I've worked with. > > I agree with David B. in theory, but David M. (gee, that's confusing...) > in practice. I think that equality, and assumptions about equality, > have some side effects. For example, if two objects compared through > equals() return true, then I expect to be able to use the object > interchangeable. You expect wrong; sorry. Look at the spec for java.lang.Object.equals(); it guarantees quite a few properties (reflexive, symmetric, transitive, consistent, ...) but NOT substitutability. (Use "==" or some specialized method for that.) > So I think equals() isn't a good idea; however, something like <code>if > (name1.sameNamespace(name2))</code> or something equivalent (not the > best example, but you get the idea) doesn't offend my eyes.... for what > it's worth. Were there to be a Name class that couldn't be used as a hashtable key to get the expected effect, then it'd be unusable. You're suggesting that, in effect. - Dave 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 unsubscribe, mailto:majordomo@i... the following message; unsubscribe 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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