| /* |
| * 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 org.apache.directory.shared.ldap.filter.ScopeNode; |
| import org.apache.directory.shared.ldap.filter.SearchScope; |
| import org.apache.directory.server.xdbm.IndexEntry; |
| import org.apache.directory.server.xdbm.Store; |
| import org.apache.directory.server.xdbm.search.Evaluator; |
| |
| |
| /** |
| * Evaluates ScopeNode assertions with subtree scope on candidates using an |
| * entry database. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| * @version $Rev$ |
| */ |
| public class SubtreeScopeEvaluator<E> implements Evaluator<ScopeNode,E> |
| { |
| /** The ScopeNode containing initial search scope constraints */ |
| private final ScopeNode node; |
| |
| /** The entry identifier of the scope base */ |
| private final Long baseId; |
| |
| /** |
| * Whether or not to accept all candidates. If this evaluator's baseId is |
| * set to the context entry's id, then obviously all candidates will be |
| * subordinate to this root ancestor or in subtree scope. This check is |
| * done on initialization and used there after. One reason we need do |
| * this is because the subtree scope index (sub level index) does not map |
| * the values for the context entry id to it's subordinates since it would |
| * have to include all entries. This is a waste of space and lookup time |
| * since we know all entries will be subordinates in this case. |
| */ |
| private final boolean baseIsContextEntry; |
| |
| /** True if the scope requires alias dereferencing while searching */ |
| private final boolean dereferencing; |
| |
| /** The entry database/store */ |
| private final Store<E> db; |
| |
| |
| /** |
| * Creates a subtree scope node evaluator for search expressions. |
| * |
| * @param node the scope node |
| * @param db the database used to evaluate scope node |
| * @throws Exception on db access failure |
| */ |
| public SubtreeScopeEvaluator( Store<E> db, ScopeNode node ) throws Exception |
| { |
| this.db = db; |
| this.node = node; |
| |
| if ( node.getScope() != SearchScope.SUBTREE ) |
| { |
| throw new IllegalStateException( "ScopeNode is not of subtree scope." ); |
| } |
| |
| baseId = db.getEntryId( node.getBaseDn() ); |
| baseIsContextEntry = getContextEntryId() == baseId; |
| dereferencing = node.getDerefAliases().isDerefInSearching() || |
| node.getDerefAliases().isDerefAlways(); |
| } |
| |
| |
| private Long contextEntryId; |
| |
| |
| private Long getContextEntryId() |
| { |
| if ( contextEntryId == null ) |
| { |
| try |
| { |
| this.contextEntryId = db.getEntryId( db.getSuffix().getNormName() ); |
| } |
| catch ( Exception e ) |
| { |
| // might not have been created |
| // might not have been created |
| } |
| } |
| |
| if ( contextEntryId == null ) |
| { |
| return 1L; |
| } |
| |
| return contextEntryId; |
| } |
| |
| |
| /** |
| * Asserts whether or not a candidate has one level scope while taking |
| * alias dereferencing into account. |
| * |
| * @param candidate the entry tested to see if it is in subtree scope |
| * @return true if the candidate is within one level scope whether or not |
| * alias dereferencing is enabled. |
| * @throws Exception if the index lookups fail. |
| * @see Evaluator#evaluate(org.apache.directory.server.xdbm.IndexEntry) |
| */ |
| public boolean evaluate( IndexEntry<?,E> candidate ) throws Exception |
| { |
| /* |
| * This condition catches situations where the candidate is equal to |
| * the base entry and when the base entry is the context entry. Note |
| * we do not store a mapping in the subtree index of the context entry |
| * to all it's subordinates since that would be the entire set of |
| * entries in the db. |
| */ |
| if ( baseIsContextEntry || baseId.longValue() == candidate.getId().longValue() ) |
| { |
| return true; |
| } |
| |
| boolean isDescendant = db.getSubLevelIndex().forward( baseId, candidate.getId() ); |
| |
| /* |
| * The candidate id could be any entry in the db. If search |
| * dereferencing is not enabled then we return the results of the |
| * descendant test. |
| */ |
| if ( ! isDereferencing() ) |
| { |
| return isDescendant; |
| } |
| |
| /* |
| * From here down alias dereferencing is enabled. We determine if the |
| * candidate id is an alias, if so we reject it since aliases should |
| * not be returned. |
| */ |
| if ( null != db.getAliasIndex().reverseLookup( candidate.getId() ) ) |
| { |
| return false; |
| } |
| |
| /* |
| * The candidate is NOT an alias at this point. So if it is a |
| * descendant we just return true since it is in normal subtree scope. |
| */ |
| if ( isDescendant ) |
| { |
| return true; |
| } |
| |
| /* |
| * At this point the candidate is not a descendant and it is not an |
| * alias. We need to check if the candidate is in extended subtree |
| * scope by performing a lookup on the subtree alias index. This index |
| * stores a tuple mapping the baseId to the ids of objects brought |
| * into subtree scope of the base by an alias: |
| * |
| * ( baseId, aliasedObjId ) |
| * |
| * If the candidate id is an object brought into subtree scope then |
| * the lookup returns true accepting the candidate. Otherwise the |
| * candidate is rejected with a false return because it is not in scope. |
| */ |
| return db.getSubAliasIndex().forward( baseId, candidate.getId() ); |
| } |
| |
| |
| /** |
| * Asserts whether or not a candidate has one level scope while taking |
| * alias dereferencing into account. |
| * |
| * @param id the id of the entry tested to see if it is in subtree scope |
| * @return true if the candidate is within one level scope whether or not |
| * alias dereferencing is enabled. |
| * @throws Exception if the index lookups fail. |
| * @see Evaluator#evaluate(org.apache.directory.server.xdbm.IndexEntry) |
| */ |
| public boolean evaluate( Long id ) throws Exception |
| { |
| boolean isDescendant = db.getSubLevelIndex().forward( baseId, id ); |
| |
| /* |
| * The candidate id could be any entry in the db. If search |
| * dereferencing is not enabled then we return the results of the |
| * descendant test. |
| */ |
| if ( ! isDereferencing() ) |
| { |
| return isDescendant; |
| } |
| |
| /* |
| * From here down alias dereferencing is enabled. We determine if the |
| * candidate id is an alias, if so we reject it since aliases should |
| * not be returned. |
| */ |
| if ( null != db.getAliasIndex().reverseLookup( id ) ) |
| { |
| return false; |
| } |
| |
| /* |
| * The candidate is NOT an alias at this point. So if it is a |
| * descendant we just return true since it is in normal subtree scope. |
| */ |
| if ( isDescendant ) |
| { |
| return true; |
| } |
| |
| /* |
| * At this point the candidate is not a descendant and it is not an |
| * alias. We need to check if the candidate is in extended subtree |
| * scope by performing a lookup on the subtree alias index. This index |
| * stores a tuple mapping the baseId to the ids of objects brought |
| * into subtree scope of the base by an alias: |
| * |
| * ( baseId, aliasedObjId ) |
| * |
| * If the candidate id is an object brought into subtree scope then |
| * the lookup returns true accepting the candidate. Otherwise the |
| * candidate is rejected with a false return because it is not in scope. |
| */ |
| return db.getSubAliasIndex().forward( baseId, id ); |
| } |
| |
| |
| /** |
| * Asserts whether or not a candidate has one level scope while taking |
| * alias dereferencing into account. |
| * |
| * @param candidate the entry tested to see if it is in subtree scope |
| * @return true if the candidate is within one level scope whether or not |
| * alias dereferencing is enabled. |
| * @throws Exception if the index lookups fail. |
| * @see Evaluator#evaluate(org.apache.directory.server.xdbm.IndexEntry) |
| */ |
| public boolean evaluate( E candidate ) throws Exception |
| { |
| throw new UnsupportedOperationException( "This is too inefficient without getId() on ServerEntry" ); |
| } |
| |
| |
| public ScopeNode getExpression() |
| { |
| return node; |
| } |
| |
| |
| public Long getBaseId() |
| { |
| return baseId; |
| } |
| |
| |
| public boolean isDereferencing() |
| { |
| return dereferencing; |
| } |
| } |