org.apache.directory.server.xdbm.search.impl
Class DefaultOptimizer<E>

java.lang.Object
  org.apache.directory.server.xdbm.search.impl.DefaultOptimizer<E>

All Implemented Interfaces:

Optimizer

public class DefaultOptimizer<E>
extends java.lang.Object
implements Optimizer

Optimizer that annotates the filter using scan counts.

Version:

$Rev: 689396 $

Author:

Apache Directory Project

Constructor Summary

DefaultOptimizer(Store<E> db)
Creates an optimizer on a database.

Method Summary

java.lang.Long

annotate(org.apache.directory.shared.ldap.filter.ExprNode node) Annotates the expression tree to determine optimal evaluation order based on the scan count for indices that exist for each expression node.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DefaultOptimizer

public DefaultOptimizer(Store<E> db)
                 throws java.lang.Exception

Creates an optimizer on a database.

Parameters:

db - the database this optimizer works for.

Throws:

java.lang.Exception

Method Detail

annotate

public java.lang.Long annotate(org.apache.directory.shared.ldap.filter.ExprNode node)
                        throws java.lang.Exception

Annotates the expression tree to determine optimal evaluation order based on the scan count for indices that exist for each expression node. If an index on the attribute does not exist an IndexNotFoundException will be thrown.

Specified by:

annotate in interface Optimizer

Parameters:

node - the root of the expression node tree

Throws:

java.lang.Exception - if there are failures while optimizing

See Also:

Optimizer.annotate(ExprNode)