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RE: Unwanted (?) exceptions in DDR Simple API spec

From: JOSE MANUEL CANTERA FONSECA <jmcf@tid.es>
Date: Thu, 26 Nov 2009 09:12:56 +0100
To: Jo Rabin <jrabin@mtld.mobi>, "public-ddwg@w3.org" <public-ddwg@w3.org>
Message-id: <93AA9E47B82F684A868C217766F489053A9769ABA1@EXCLU2K7.hi.inet>
Hi Jo,

although it can be possible I would not recommend it for the sake of robustness of the code, imagine for instance  a situation in which the names of the properties are obtained dynamically (for example from a file) and you end up having the name of a property which does not exist. If you don't capture exceptions explicitly your program will end unexpectedly and won't be able to recover from a simple error 

So I would not take advantage of holes in the spec to satisfy certain use cases and leave the door open to break other situations Actually the majority of exceptions in Java APIs are regular exceptions that have to be captured explicitly

Best Regards


-----Mensaje original-----
De: public-ddwg-request@w3.org [mailto:public-ddwg-request@w3.org] En nombre de Jo Rabin
Enviado el: miƩrcoles, 25 de noviembre de 2009 16:06
Para: public-ddwg@w3.org
Asunto: Unwanted (?) exceptions in DDR Simple API spec

Dear Survivor of the DDWG (as Francois put it :-) )

A question I've been meaning to put to colleagues is ref the 
specification of Exceptions in the API. I've been working with a Java 
implementation for some time now and frequently end up with something 
like this:

try {
    pvv = service.getPropertyValues(evidence);
} catch (NameException e1) {
    // can't get here
    e1.printStackTrace();
}

for (PropertyValue pv: pvv.getAll()) {
    try {
       System.out.println(pv.getString());
    } catch (ValueException e) {
       // can't get here
       e.printStackTrace();
    }
}

It seems to me that there is a strong case for changing the exception 
types to avoid this unnecessary round the houses. Interestingly enough, 
though DDRException subclasses Exception in the supplied Java, it is not 
stated explicitly in the API documentation that this is the case. Would 
it be acceptable for a conforming implementation to have DDRException 
subclass SystemException, I wonder?

thanks
Jo





Received on Thursday, 26 November 2009 08:13:33 UTC

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