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.core.event;
021    
022    
023    import org.apache.directory.shared.ldap.entry.ServerEntry;
024    import org.apache.directory.shared.ldap.exception.LdapException;
025    import org.apache.directory.shared.ldap.filter.ExprNode;
026    
027    
028    /**
029     * Tests if an entry is eligible for return by evaluating a filter expression on
030     * the candidate.  The evaluation can proceed by applying the filter on the 
031     * attributes of the entry itself or indices can be used for rapid evaluation.
032     * 
033     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
034     * @version $Rev: 927146 $
035     */
036    public interface Evaluator
037    {
038        /**
039         * Evaluates a candidate to determine if a filter expression selects it.
040         * 
041         * @param node the filter expression to evaluate on the candidate
042         * @param dn the normalized distinguished name of the entry being tested
043         * @param entry the entry to evaluate
044         * @return true if the filter selects the candidate false otherwise
045         * @throws LdapException if there is a database fault during evaluation
046         */
047        boolean evaluate( ExprNode node, String dn, ServerEntry entry ) throws LdapException;
048    }