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Posted to dev@commons.apache.org by Elliotte Harold <el...@metalab.unc.edu> on 2005/05/04 15:05:00 UTC
JXPath cycles
How does Commons JXPath handle cycles when querying JavaBeans? For
instance suppose bean A has a property X whose value is a reference to
bean B. Suppose also bean B has a property Y whose value is a reference
to bean A. Then suppose, starting with bean A as the context node, we
make the query .//*. What happens and why? Is it an infinite loop?
This is a simple case, but clearly the cycle could be longer than length 2.
--
Elliotte Rusty Harold elharo@metalab.unc.edu
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Re: JXPath cycles
Posted by Dmitri Plotnikov <dm...@apache.org>.
Elliotte,
While traversing the graph of model objects, JXPath maintains a trace of
nodes it's visited. If it encouters a node that has already been visited,
it simply skips it. That's how it avoids the infinite loop in a situation
like the one you are describing.
I hope this helps,
- Dmitri
----- Original Message -----
From: "Elliotte Harold" <el...@metalab.unc.edu>
To: <co...@jakarta.apache.org>
Sent: Wednesday, May 04, 2005 9:05 AM
Subject: JXPath cycles
> How does Commons JXPath handle cycles when querying JavaBeans? For
> instance suppose bean A has a property X whose value is a reference to
> bean B. Suppose also bean B has a property Y whose value is a reference to
> bean A. Then suppose, starting with bean A as the context node, we make
> the query .//*. What happens and why? Is it an infinite loop?
>
> This is a simple case, but clearly the cycle could be longer than length
> 2.
>
> --
> Elliotte Rusty Harold elharo@metalab.unc.edu
> XML in a Nutshell 3rd Edition Just Published!
> http://www.cafeconleche.org/books/xian3/
> http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: commons-dev-help@jakarta.apache.org
>
>
>
>
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