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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  package org.apache.directory.server.xdbm.search.impl;
21  
22  import javax.naming.NamingException;
23  
24  import org.apache.directory.shared.ldap.filter.BranchNode;
25  import org.apache.directory.shared.ldap.filter.ExprNode;
26  import org.apache.directory.server.xdbm.search.Optimizer;
27  
28  
29  /**
30   * A do nothing optimizer which labels all nodes with <code>
31   * BigInteger.valueOf( Integer.MAX_VALUE ) </code>, instead of actually 
32   * taking scan counts.
33   * 
34   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
35   * @version $Rev$, $Date$
36   */
37  public class NoOpOptimizer implements Optimizer
38  {
39      /** the maximum size for a count Integer.MAX_VALUE as a BigInteger */
40      private static final Long MAX = Long.MAX_VALUE;
41      
42      public Long annotate( ExprNode node ) throws NamingException
43      {
44          if ( node.isLeaf() )
45          {
46              node.set( "count", MAX );
47              return MAX;
48          }
49          
50          BranchNode bnode = ( BranchNode ) node;
51          if ( bnode.getChildren().size() == 0 )
52          {
53              bnode.set( "count", MAX );
54              return MAX;
55          }
56          
57          final int limit = bnode.getChildren().size();
58          for ( int ii = 0; ii < limit; ii++ )
59          {
60              ExprNode child = bnode.getChildren().get( ii );
61              if ( child.isLeaf() )
62              {
63                  child.set( "count", MAX );
64              }
65              else
66              {
67                  annotate( child );
68              }
69          }
70  
71          bnode.set( "count", MAX );
72          return MAX;
73      }
74  }