/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.directory.server.xdbm.search.impl;
import javax.naming.directory.SearchControls;
import org.apache.directory.server.core.partition.Partition;
import org.apache.directory.server.i18n.I18n;
import org.apache.directory.server.xdbm.EmptyIndexCursor;
import org.apache.directory.server.xdbm.ForwardIndexEntry;
import org.apache.directory.server.xdbm.IndexCursor;
import org.apache.directory.server.xdbm.IndexEntry;
import org.apache.directory.server.xdbm.SingletonIndexCursor;
import org.apache.directory.server.xdbm.Store;
import org.apache.directory.server.xdbm.search.Evaluator;
import org.apache.directory.server.xdbm.search.Optimizer;
import org.apache.directory.server.xdbm.search.SearchEngine;
import org.apache.directory.shared.ldap.model.entry.Entry;
import org.apache.directory.shared.ldap.model.exception.LdapNoSuchObjectException;
import org.apache.directory.shared.ldap.model.filter.AndNode;
import org.apache.directory.shared.ldap.model.filter.BranchNode;
import org.apache.directory.shared.ldap.model.filter.ExprNode;
import org.apache.directory.shared.ldap.model.filter.ScopeNode;
import org.apache.directory.shared.ldap.model.message.AliasDerefMode;
import org.apache.directory.shared.ldap.model.message.SearchScope;
import org.apache.directory.shared.ldap.model.name.Dn;
/**
* 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>
*/
public class DefaultSearchEngine<ID extends Comparable<ID>> implements SearchEngine<Entry, ID>
{
/** the Optimizer used by this DefaultSearchEngine */
private final Optimizer optimizer;
/** the Database this DefaultSearchEngine operates on */
private final Store<Entry, ID> db;
/** creates Cursors over entries satisfying filter expressions */
private final CursorBuilder<ID> cursorBuilder;
/** creates evaluators which check to see if candidates satisfy a filter expression */
private final EvaluatorBuilder<ID> evaluatorBuilder;
// ------------------------------------------------------------------------
// C O N S T R U C T O R S
// ------------------------------------------------------------------------
/**
* Creates a DefaultSearchEngine for searching a Database without setting
* up the database.
* @param db the btree based partition
* @param cursorBuilder an expression cursor builder
* @param evaluatorBuilder an expression evaluator builder
* @param optimizer an optimizer to use during search
*/
public DefaultSearchEngine( Store<Entry, ID> db, CursorBuilder<ID> cursorBuilder,
EvaluatorBuilder<ID> evaluatorBuilder, Optimizer optimizer )
{
this.db = db;
this.optimizer = optimizer;
this.cursorBuilder = cursorBuilder;
this.evaluatorBuilder = evaluatorBuilder;
}
/**
* Gets the optimizer for this DefaultSearchEngine.
*
* @return the optimizer
*/
public Optimizer getOptimizer()
{
return optimizer;
}
/**
* @see SearchEngine#cursor(org.apache.directory.shared.ldap.model.name.Dn, org.apache.directory.shared.ldap.model.message.AliasDerefMode, ExprNode, SearchControls)
*/
public IndexCursor<ID, Entry, ID> cursor( Dn base, AliasDerefMode aliasDerefMode, ExprNode filter,
SearchControls searchCtls ) throws Exception
{
Dn effectiveBase;
ID baseId = db.getEntryId( base );
// Check that we have an entry, otherwise we can immediately get out
if ( baseId == null )
{
if ( ((Partition)db).getSuffixDn().equals( base ) )
{
// The context entry is not created yet, return an empty cursor
return new EmptyIndexCursor<ID, Entry, ID>();
}
else
{
// The search base doesn't exist
throw new LdapNoSuchObjectException( I18n.err( I18n.ERR_648, base ) );
}
}
String aliasedBase = db.getAliasIndex().reverseLookup( baseId );
// --------------------------------------------------------------------
// Determine the effective base with aliases
// --------------------------------------------------------------------
/*
* If the base is not an alias or if alias dereferencing does not
* occur on finding the base then we set the effective base to the
* given base.
*/
if ( ( null == aliasedBase ) || !aliasDerefMode.isDerefFindingBase() )
{
effectiveBase = base;
}
/*
* If the base is an alias and alias dereferencing does occur on
* finding the base then we set the effective base to the alias target
* got from the alias index.
*/
else
{
effectiveBase = new Dn( aliasedBase );
}
// --------------------------------------------------------------------
// Specifically Handle Object Level Scope
// --------------------------------------------------------------------
if ( searchCtls.getSearchScope() == SearchControls.OBJECT_SCOPE )
{
ID effectiveBaseId = baseId;
if ( effectiveBase != base )
{
effectiveBaseId = db.getEntryId( effectiveBase );
}
IndexEntry<ID, Entry, ID> indexEntry = new ForwardIndexEntry<ID, Entry, ID>();
indexEntry.setId( effectiveBaseId );
optimizer.annotate( filter );
Evaluator<? extends ExprNode, Entry, ID> evaluator = evaluatorBuilder.build( filter );
if ( evaluator.evaluate( indexEntry ) )
{
return new SingletonIndexCursor<ID, Entry, ID>( indexEntry );
}
else
{
return new EmptyIndexCursor<ID, Entry, ID>();
}
}
// Add the scope node using the effective base to the filter
BranchNode root = new AndNode();
ExprNode node = new ScopeNode( aliasDerefMode, effectiveBase, SearchScope.getSearchScope(searchCtls
.getSearchScope()) );
root.getChildren().add( node );
root.getChildren().add( filter );
// Annotate the node with the optimizer and return search enumeration.
optimizer.annotate( root );
return ( IndexCursor<ID, Entry, ID> ) cursorBuilder.build( root );
}
/**
* @see SearchEngine#evaluator(ExprNode)
*/
public Evaluator<? extends ExprNode, Entry, ID> evaluator( ExprNode filter ) throws Exception
{
return evaluatorBuilder.build( filter );
}
}