001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020 package org.apache.directory.server.xdbm.search.impl; 021 022 023 import javax.naming.directory.SearchControls; 024 025 import org.apache.directory.server.xdbm.EmptyIndexCursor; 026 import org.apache.directory.server.xdbm.ForwardIndexEntry; 027 import org.apache.directory.server.xdbm.IndexCursor; 028 import org.apache.directory.server.xdbm.IndexEntry; 029 import org.apache.directory.server.xdbm.SingletonIndexCursor; 030 import org.apache.directory.server.xdbm.Store; 031 import org.apache.directory.server.xdbm.search.Evaluator; 032 import org.apache.directory.server.xdbm.search.Optimizer; 033 import org.apache.directory.server.xdbm.search.SearchEngine; 034 import org.apache.directory.shared.ldap.entry.ServerEntry; 035 import org.apache.directory.shared.ldap.filter.AndNode; 036 import org.apache.directory.shared.ldap.filter.BranchNode; 037 import org.apache.directory.shared.ldap.filter.ExprNode; 038 import org.apache.directory.shared.ldap.filter.ScopeNode; 039 import org.apache.directory.shared.ldap.filter.SearchScope; 040 import org.apache.directory.shared.ldap.message.AliasDerefMode; 041 import org.apache.directory.shared.ldap.name.DN; 042 043 044 /** 045 * Given a search filter and a scope the search engine identifies valid 046 * candidate entries returning their ids. 047 * 048 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 049 * @version $Rev: 927146 $ 050 */ 051 public class DefaultSearchEngine<ID> implements SearchEngine<ServerEntry, ID> 052 { 053 /** the Optimizer used by this DefaultSearchEngine */ 054 private final Optimizer optimizer; 055 /** the Database this DefaultSearchEngine operates on */ 056 private final Store<ServerEntry, ID> db; 057 /** creates Cursors over entries satisfying filter expressions */ 058 private final CursorBuilder<ID> cursorBuilder; 059 /** creates evaluators which check to see if candidates satisfy a filter expression */ 060 private final EvaluatorBuilder<ID> evaluatorBuilder; 061 062 063 // ------------------------------------------------------------------------ 064 // C O N S T R U C T O R S 065 // ------------------------------------------------------------------------ 066 067 /** 068 * Creates a DefaultSearchEngine for searching a Database without setting 069 * up the database. 070 * @param db the btree based partition 071 * @param cursorBuilder an expression cursor builder 072 * @param evaluatorBuilder an expression evaluator builder 073 * @param optimizer an optimizer to use during search 074 */ 075 public DefaultSearchEngine( Store<ServerEntry, ID> db, CursorBuilder<ID> cursorBuilder, 076 EvaluatorBuilder<ID> evaluatorBuilder, Optimizer optimizer ) 077 { 078 this.db = db; 079 this.optimizer = optimizer; 080 this.cursorBuilder = cursorBuilder; 081 this.evaluatorBuilder = evaluatorBuilder; 082 } 083 084 085 /** 086 * Gets the optimizer for this DefaultSearchEngine. 087 * 088 * @return the optimizer 089 */ 090 public Optimizer getOptimizer() 091 { 092 return optimizer; 093 } 094 095 096 /** 097 * @see SearchEngine#cursor(DN, AliasDerefMode, ExprNode, SearchControls) 098 */ 099 public IndexCursor<ID, ServerEntry, ID> cursor( DN base, AliasDerefMode aliasDerefMode, ExprNode filter, 100 SearchControls searchCtls ) throws Exception 101 { 102 DN effectiveBase; 103 ID baseId = db.getEntryId( base.getNormName() ); 104 105 // Check that we have an entry, otherwise we can immediately get out 106 if ( baseId == null ) 107 { 108 // The entry is not found : ciao ! 109 return new EmptyIndexCursor<ID, ServerEntry, ID>(); 110 } 111 112 String aliasedBase = db.getAliasIndex().reverseLookup( baseId ); 113 114 // -------------------------------------------------------------------- 115 // Determine the effective base with aliases 116 // -------------------------------------------------------------------- 117 118 /* 119 * If the base is not an alias or if alias dereferencing does not 120 * occur on finding the base then we set the effective base to the 121 * given base. 122 */ 123 if ( ( null == aliasedBase ) || !aliasDerefMode.isDerefFindingBase() ) 124 { 125 effectiveBase = base; 126 } 127 128 /* 129 * If the base is an alias and alias dereferencing does occur on 130 * finding the base then we set the effective base to the alias target 131 * got from the alias index. 132 */ 133 else 134 { 135 effectiveBase = new DN( aliasedBase ); 136 } 137 138 // -------------------------------------------------------------------- 139 // Specifically Handle Object Level Scope 140 // -------------------------------------------------------------------- 141 142 if ( searchCtls.getSearchScope() == SearchControls.OBJECT_SCOPE ) 143 { 144 ID effectiveBaseId = baseId; 145 if ( effectiveBase != base ) 146 { 147 effectiveBaseId = db.getEntryId( effectiveBase.getNormName() ); 148 } 149 150 IndexEntry<ID, ServerEntry, ID> indexEntry = new ForwardIndexEntry<ID, ServerEntry, ID>(); 151 indexEntry.setId( effectiveBaseId ); 152 optimizer.annotate( filter ); 153 Evaluator<? extends ExprNode, ServerEntry, ID> evaluator = evaluatorBuilder.build( filter ); 154 155 if ( evaluator.evaluate( indexEntry ) ) 156 { 157 return new SingletonIndexCursor<ID, ServerEntry, ID>( indexEntry ); 158 } 159 else 160 { 161 return new EmptyIndexCursor<ID, ServerEntry, ID>(); 162 } 163 } 164 165 // Add the scope node using the effective base to the filter 166 BranchNode root = new AndNode(); 167 ExprNode node = new ScopeNode( aliasDerefMode, effectiveBase.getNormName(), SearchScope.getSearchScope( searchCtls 168 .getSearchScope() ) ); 169 root.getChildren().add( node ); 170 root.getChildren().add( filter ); 171 172 // Annotate the node with the optimizer and return search enumeration. 173 optimizer.annotate( root ); 174 return ( IndexCursor<ID, ServerEntry, ID> ) cursorBuilder.build( root ); 175 } 176 177 178 /** 179 * @see SearchEngine#evaluator(ExprNode) 180 */ 181 public Evaluator<? extends ExprNode, ServerEntry, ID> evaluator( ExprNode filter ) throws Exception 182 { 183 return evaluatorBuilder.build( filter ); 184 } 185 }