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1   /*
2    *   Copyright 2004 The Apache Software Foundation
3    *
4    *   Licensed under the Apache License, Version 2.0 (the "License");
5    *   you may not use this file except in compliance with the License.
6    *   You may obtain a copy of the License at
7    *
8    *       http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *   Unless required by applicable law or agreed to in writing, software
11   *   distributed under the License is distributed on an "AS IS" BASIS,
12   *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *   See the License for the specific language governing permissions and
14   *   limitations under the License.
15   *
16   */
17  package org.apache.ldap.server.event;
18  
19  
20  import javax.naming.NamingException;
21  import javax.naming.directory.Attributes;
22  
23  import org.apache.ldap.common.filter.ExprNode;
24  
25  
26  /***
27   * Tests if an entry is eligable for return by evaluating a filter expression on
28   * the candidate.  The evaluation can proceed by applying the filter on the 
29   * attributes of the entry itself or indices can be used for rapid evaluation.
30   * 
31   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
32   * @version $Rev$
33   */
34  public interface Evaluator
35  {
36      /***
37       * Evaluates a candidate to determine if a filter expression selects it.
38       * 
39       * @param node the filter expression to evaluate on the candidate
40       * @param dn the normalized distinguished name of the entry being tested
41       * @param entry the entry to evaluate
42       * @return true if the filter selects the candidate false otherwise
43       * @throws javax.naming.NamingException if there is a database fault during evaluation
44       */
45      boolean evaluate( ExprNode node, String dn, Attributes entry ) throws NamingException;
46  }