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From "Alex Karasulu" <akaras...@apache.org>
Subject [ApacheDS] [Search] Adding additional methods to Evaluator interface
Date Tue, 13 May 2008 05:15:30 GMT
In the Cursor based refactoring I've noticed some inefficiencies with the
way we deal with Evaluators.  For more information about what these are
please see the developer documentation on the default partition
implementation and how search is conducted on it here [0].

The Evaluator interface is used to determine whether or not a filter
expression accepts a candidate entry.  Evaluators have an AST representation
of the expression or subexpression they use to determine if the candidate
matches the expression filter.  Right now we use evaluate( IndexEntry )
which contains the id and value along with the entry if it is pulled from
the master table.  This is to temporarily store the entry so subsequent
evaluation attempts do not have to access the master table again to get the
entry.  It makes search a lot faster.

I was seeing some use cases in unit tests and Cursor implementations that
use evaluators which don't necessarily need to pass in an IndexEntry.
Instead they need to pass in a ServerEntry or a Long id for the candidate.
In some cases a new IndexEntry object is created just to be able to utilize
the Evaluator.  So I'm going to change this interface so it adds these
additional overloads:

    boolean evaluate( IndexEntry<?,E> entry ) throws Exception;
    boolean evaluate( Long id ) throws Exception;
    boolean evaluate( E entry ) throws Exception;

Any objections?

Thanks,
Alex

--------
[0] -
http://cwiki.apache.org/confluence/display/DIRxSRVx11/SearchEngine+and+Optimizer

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