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From Andy Depue <a...@marathon-man.com>
Subject [JXPath] indexing List properties for xpath
Date Fri, 11 Jun 2004 20:17:48 GMT
I have an object model that contains several very large List properties, such 
as:
  public List getRelations();
The List could contain thousands of elements.  I am able to query such List 
properties using JXPath:
  relations[entity/id=12]
However, since the List can be extremely large, and since the object model 
doesn't give me much freedom to change it (such as replacing the List with a 
Map), searching the enter List can be very slow and I'm seeing it impact 
performance.  I would like to somehow index the property, much like you would 
index a table in a DB.  I'm thinking of creating an indexing interface for my 
project, something I could use like so:
  indexor.indexProperty(contextObject, "relations", "entity/id");
Which would index all elements in the "relations" List property on their 
"entity/id" property.  Thus, whenever an XPath filters a node selection based 
on the entity/id property, it would pick up and use the index instead of 
scanning the entire List (much like a DB).  Before I plunge into JXPath 
source code, I thought it might be worth asking if anyone who is familiar 
with JXPath could recommend the best way to modify/extend JXPath in order to 
implement this indexing scheme for my project?

Thanks,
  Andy

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