[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: SAX/Java Proposed Changes


throw throws in java
At 8:18 AM +0100 3/10/04, Jochen Wiedmann wrote:

>Not quite like the paradigm of exception handling (catch the
>exception in one place).

Throw is different from catch. If you throw a SAXException, then 
you're not handling it in that method, which is why you're throwing 
it; but you do make the decision of how to configure the object 
before throwing the exception. IN many cases you may not need to do 
any cleanup at all and can leave the object in an invalid state. You 
know whether or not you have to clean up, and what needs to be 
cleaned up because you've chosen to throw the exception. This is the 
qualitative difference from an exception the parser throws due to bad 
input.

>But besides: Who tells you, that *I*
>am throwing the Exception and not, for example, another ContentHandler
>which I invoke?
>

If the other ContentHandler method is declared to throw a 
SAXException (the only checked exception it can throw) and you need 
to do cleanup, catch it and respond to it and then rethrow it. You 
still know where and when the exception can be thrown, which you do 
not know for a parser thrown exception.

By the way, although most of the time you can catch an exception in 
one place, that's not a rule written in stone. It does happen in more 
complicated situations that one catch block has to clean up in one 
method and then throw the same or a different exception up to another 
method, often in a different class. One of the benefits of the 
exception approach compared to traditional error handling is the easy 
reversal of the call chain, thus making complicated, multilayered 
responses possible.
-- 

   Elliotte Rusty Harold
   elharo@m...
   Effective XML (Addison-Wesley, 2003)
   http://www.cafeconleche.org/books/effectivexml
   http://www.amazon.com/exec/obidos/ISBN%3D0321150406/ref%3Dnosim/cafeaulaitA

  • Follow-Ups:
    • SAX CVS
      • From: David Megginson <dmeggin@a...>

PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
Email
First Name
Last Name
Company
Subscribe in XML format
RSS 2.0
Atom 0.3
 

Stylus Studio has published XML-DEV in RSS and ATOM formats, enabling users to easily subcribe to the list from their preferred news reader application.


Stylus Studio Sponsored Links are added links designed to provide related and additional information to the visitors of this website. they were not included by the author in the initial post. To view the content without the Sponsor Links please click here.

Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.