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Re: [Exist-open] Null Pointer Exception after doing XQuery updates
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From: Dan M. <dan...@gm...> - 2014-07-08 12:35:23
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Hello Wolfgang,
Thank you for your quick response!
Your comment that the *name()* function is the root cause of the problem
seems to be correct. I only had a single place in the scripts that called
it.
Here is a summary of the offending line that was causing the Java Null
Pointer Exception. What I was doing was looking through a library system
EAD file "finding aids" for all elements that had the element name
"corpname":
* let $name-elements := collection('/db/apps/mnhs/data-ead')//*.*[name(.)
= 'corpname']*
what I realized was that the first period in the path expression included
items that were not true XML "elements" but might also include document
nodes, comments, PIs and other non-elements. So by changing the line to be
the following:
* let $name-elements := collection('/db/apps/mnhs/data-ead')//*[name(.) =
'corpname']*
All the NPE errors immediately went away. This filtered out the non
element nodes that correctly had names. I did have some data corruption
but a reload seems to have fixed this. So all I did was replace the period
after the "//" with a asterix which then ONLY selected elements, not other
node types.
Thanks! - Dan
On Tue, Jul 8, 2014 at 1:36 AM, <wol...@ex...> wrote:
> Hi Dan,
>
> > I am getting a strange Java Null Pointer Exception after I do a set up
> update operations. The first set up updates seem to work but after that
> they all seem to fail.
>
> Could you check if the parameter you pass to fn:name is a variable whose
> value was assigned before the update? The variable may hold a reference to
> a node which was moved or removed during the update and thus became
> invalid. This would explain the issue (for sure it should not lead to a
> NullPointer exception but yield an error). Could you send me the relevant
> part of the query?
>
> Wolfgang
--
Dan McCreary
http://danmccreary.com
Co-author: Making Sense of NoSQL <http://manning.com/mccreary>
office: (952) 931-9198
cell: (612) 986-1552
skype: dmccreary47
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