/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.ldap.server.partition.impl.btree;
import java.math.BigInteger;
import java.util.Map;
import javax.naming.Name;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.SearchControls;
import org.apache.ldap.common.filter.AbstractExprNode;
import org.apache.ldap.common.filter.BranchNode;
import org.apache.ldap.common.filter.ExprNode;
import org.apache.ldap.common.filter.ScopeNode;
import org.apache.ldap.common.message.DerefAliasesEnum;
import org.apache.ldap.common.name.LdapName;
/**
* Given a search filter and a scope the search engine identifies valid
* candidate entries returning their ids.
*
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $Rev: 307079 $
*/
public class DefaultSearchEngine implements SearchEngine
{
/** the Optimizer used by this DefaultSearchEngine */
private final Optimizer optimizer;
/** the Database this DefaultSearchEngine operates on */
private BTreeDirectoryPartition db;
/** Evaluator flyweight used for filter expression assertions */
private ExpressionEvaluator evaluator;
/** Enumerator flyweight that creates enumerations on filter expressions */
private ExpressionEnumerator enumerator;
// ------------------------------------------------------------------------
// C O N S T R U C T O R S
// ------------------------------------------------------------------------
/**
* Creates a DefaultSearchEngine for searching a Database without setting
* up the database.
*/
public DefaultSearchEngine( BTreeDirectoryPartition db,
ExpressionEvaluator evaluator,
ExpressionEnumerator enumerator )
{
this.db = db;
this.evaluator = evaluator;
this.enumerator = enumerator;
optimizer = new DefaultOptimizer( db );
}
/**
* Gets the optimizer for this DefaultSearchEngine.
*
* @return the optimizer
*/
public Optimizer getOptimizer()
{
return optimizer;
}
/**
* @see SearchEngine#search(Name, Map, ExprNode,SearchControls)
*/
public NamingEnumeration search( Name base, Map env, ExprNode filter,
SearchControls searchCtls )
throws NamingException
{
Name effectiveBase = null;
BigInteger baseId = db.getEntryId( base.toString() );
String aliasedBase = ( String ) db.getAliasIndex().reverseLookup( baseId );
DerefAliasesEnum mode = DerefAliasesEnum.getEnum( env );
// --------------------------------------------------------------------
// Determine the eective base with aliases
// --------------------------------------------------------------------
/*
* If the base is not an alias or if alias dereerencing does not
* occur on finding the base then we set the effective base to the
* given base.
*/
if ( null == aliasedBase || ! mode.derefFindingBase() )
{
effectiveBase = base;
}
/*
* I the base is an alias and alias dereerencing does occur on
* inding the base then we set the eective base to the alias target
* gotten rom the alias index.
*/
else if ( null != aliasedBase ) // mode = FINDING || ALWAYS
{
effectiveBase = new LdapName( aliasedBase );
}
/*
* I the base not an alias the we just set the base to the given base
*/
else
{
effectiveBase = base;
}
// Add the scope node using the eective base to the ilter
BranchNode root = new BranchNode( AbstractExprNode.AND );
ExprNode node = new ScopeNode( env, effectiveBase.toString(),
searchCtls.getSearchScope() );
root.getChildren().add( node );
root.getChildren().add( filter );
// Annotate the node with the optimizer and return search enumeration.
optimizer.annotate( root );
return enumerator.enumerate( root );
}
/**
* @see SearchEngine#evaluate(ExprNode, BigInteger)
*/
public boolean evaluate( ExprNode ilter, BigInteger id ) throws NamingException
{
IndexRecord rec = new IndexRecord();
rec.setEntryId( id );
return evaluator.evaluate( ilter, rec );
}
}