| /* |
| * 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. |
| * |
| */ |
| |
| /* |
| * $Id$ |
| * |
| * -- (c) LDAPd Group -- |
| * -- Please refer to the LICENSE.txt file in the root directory of -- |
| * -- any LDAPd project for copyright and distribution information. -- |
| * |
| * Created on Oct 13, 2003 |
| */ |
| package org.apache.ldap.server.db; |
| |
| |
| import org.apache.ldap.common.filter.ExprNode; |
| import org.apache.ldap.common.filter.SubstringNode; |
| import org.apache.ldap.common.schema.AttributeType; |
| import org.apache.ldap.common.schema.Normalizer; |
| import org.apache.ldap.server.schema.AttributeTypeRegistry; |
| import org.apache.regexp.RE; |
| import org.apache.regexp.RESyntaxException; |
| |
| import javax.naming.NamingEnumeration; |
| import javax.naming.NamingException; |
| |
| |
| /** |
| * Enumerator that creates a NamingEnumeration over the set of candidates that |
| * satisfy a substring filter expression. |
| * |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| * @version $Rev$ |
| */ |
| public class SubstringEnumerator implements Enumerator |
| { |
| /** Database used */ |
| private final Database db; |
| /** Evaluator used is an Avalon dependent object */ |
| private final SubstringEvaluator evaluator; |
| /** the attribute type registry */ |
| private final AttributeTypeRegistry attributeTypeRegistry; |
| |
| |
| /** |
| * Creates a SubstringEnumerator for a database. |
| * |
| * @param db the database |
| * @param evaluator a substring evaluator |
| */ |
| public SubstringEnumerator( Database db, |
| AttributeTypeRegistry attributeTypeRegistry, |
| SubstringEvaluator evaluator ) |
| { |
| this.db = db; |
| this.evaluator = evaluator; |
| this.attributeTypeRegistry = attributeTypeRegistry; |
| } |
| |
| |
| // ------------------------------------------------------------------------ |
| // SubstringEnumerator Methods |
| // ------------------------------------------------------------------------ |
| |
| |
| /** |
| * @see Enumerator#enumerate( |
| * org.apache.ldap.common.filter.ExprNode) |
| */ |
| public NamingEnumeration enumerate( final ExprNode node ) |
| throws NamingException |
| { |
| RE regex = null; |
| Index idx = null; |
| final SubstringNode snode = ( SubstringNode ) node; |
| AttributeType type = attributeTypeRegistry.lookup( snode.getAttribute() ); |
| Normalizer normalizer = type.getSubstr().getNormalizer(); |
| |
| if ( db.hasUserIndexOn( snode.getAttribute() ) ) |
| { |
| /* |
| * Build out regex in this block so we do not do it twice in the |
| * evaluator if there is no index on the attribute of the substr ava |
| */ |
| try |
| { |
| regex = snode.getRegex( normalizer ); |
| } |
| catch ( RESyntaxException e ) |
| { |
| NamingException ne = new NamingException( "SubstringNode '" |
| + node + "' had incorrect syntax" ); |
| ne.setRootCause( e ); |
| throw ne; |
| } |
| |
| /* |
| * Get the user index and return an index enumeration using the the |
| * compiled regular expression. Try to constrain even further if |
| * an initial term is available in the substring expression. |
| */ |
| idx = db.getUserIndex( snode.getAttribute() ); |
| if ( null == snode.getInitial() ) |
| { |
| return idx.listIndices( regex ); |
| } |
| else |
| { |
| return idx.listIndices( regex, snode.getInitial() ); |
| } |
| } |
| |
| /* |
| * From this point on we are dealing with an enumeration over entries |
| * based on an attribute that is not indexed. We have no choice but |
| * to perform a full table scan but need to leverage an index for the |
| * underlying enumeration. We know that all entries are listed under |
| * the ndn index and so this will enumerate over all entries as the |
| * underlying enumeration. An evaluator in an assertion is used to |
| * constrain the result set. |
| */ |
| NamingEnumeration underlying = db.getNdnIndex().listIndices(); |
| IndexAssertion assertion = new IndexAssertion() |
| { |
| public boolean assertCandidate( final IndexRecord record ) throws NamingException |
| { |
| return evaluator.evaluate( node, record ); |
| } |
| }; |
| |
| return new IndexAssertionEnumeration( underlying, assertion ); |
| } |
| } |