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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  
23  import org.apache.directory.shared.ldap.filter.LessEqNode;
24  import org.apache.directory.shared.ldap.schema.AttributeType;
25  import org.apache.directory.shared.ldap.schema.MatchingRule;
26  import org.apache.directory.shared.ldap.schema.Normalizer;
27  import org.apache.directory.shared.ldap.entry.Value;
28  import org.apache.directory.server.xdbm.IndexEntry;
29  import org.apache.directory.server.xdbm.Store;
30  import org.apache.directory.server.xdbm.Index;
31  import org.apache.directory.server.xdbm.search.Evaluator;
32  import org.apache.directory.server.schema.registries.Registries;
33  import org.apache.directory.server.core.entry.ServerEntry;
34  import org.apache.directory.server.core.entry.ServerAttribute;
35  
36  import java.util.Iterator;
37  import java.util.Comparator;
38  
39  
40  /**
41   * An Evaluator which determines if candidates are matched by LessEqNode
42   * assertions.
43   *
44   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
45   * @version $Rev$
46   */
47  public class LessEqEvaluator implements Evaluator<LessEqNode, ServerEntry>
48  {
49      private final LessEqNode node;
50      private final Store<ServerEntry> db;
51      private final Registries registries;
52      private final AttributeType type;
53      private final Normalizer normalizer;
54      private final Comparator comparator;
55      private final Index<Object,ServerEntry> idx;
56  
57  
58      public LessEqEvaluator( LessEqNode node, Store<ServerEntry> db, Registries registries )
59          throws Exception
60      {
61          this.db = db;
62          this.node = node;
63          this.registries = registries;
64          this.type = registries.getAttributeTypeRegistry().lookup( node.getAttribute() );
65  
66          if ( db.hasUserIndexOn( node.getAttribute() ) )
67          {
68              //noinspection unchecked
69              idx = ( Index<Object,ServerEntry> ) db.getUserIndex( node.getAttribute() );
70          }
71          else
72          {
73              idx = null;
74          }
75  
76          /*
77           * We prefer matching using the Normalizer and Comparator pair from
78           * the ordering matchingRule if one is available.  It may very well
79           * not be.  If so then we resort to using the Normalizer and
80           * Comparator from the equality matchingRule as a last resort.
81           */
82          MatchingRule mr = type.getOrdering();
83  
84          if ( mr == null )
85          {
86              mr = type.getEquality();
87          }
88  
89          if ( mr == null )
90          {
91              throw new IllegalStateException(
92                  "Could not find matchingRule to use for LessEqNode evaluation: " + node );
93          }
94  
95          normalizer = mr.getNormalizer();
96          comparator = mr.getComparator();
97      }
98  
99  
100     public LessEqNode getExpression()
101     {
102         return node;
103     }
104 
105 
106     public AttributeType getAttributeType()
107     {
108         return type;
109     }
110 
111 
112     public Normalizer getNormalizer()
113     {
114         return normalizer;
115     }
116 
117 
118     public Comparator getComparator()
119     {
120         return comparator;
121     }
122 
123 
124     public boolean evaluate( Long id ) throws Exception
125     {
126         if ( idx != null )
127         {
128             return idx.reverseLessOrEq( id, node.getValue().get() );
129         }
130 
131         return evaluate( db.lookup( id ) );
132     }
133 
134 
135     public boolean evaluate( IndexEntry<?,ServerEntry> indexEntry ) throws Exception
136     {
137         if ( idx != null )
138         {
139             return idx.reverseLessOrEq( indexEntry.getId(), node.getValue().get() );
140         }
141 
142         ServerEntry entry = indexEntry.getObject();
143 
144         // resuscitate the entry if it has not been and set entry in IndexEntry
145         if ( null == entry )
146         {
147             entry = db.lookup( indexEntry.getId() );
148             indexEntry.setObject( entry );
149         }
150         
151         if ( null == entry )
152         {
153             return false;
154         }
155 
156         // get the attribute
157         ServerAttribute attr = ( ServerAttribute ) entry.get( type );
158 
159         // if the attribute does not exist just return false
160         //noinspection unchecked
161         if ( attr != null && evaluate( ( IndexEntry<Object,ServerEntry> ) indexEntry, attr ) )
162         {
163             return true;
164         }
165 
166         // If we do not have the attribute, loop through the sub classes of
167         // the attributeType.  Perhaps the entry has an attribute value of a
168         // subtype (descendant) that will produce a match
169         if ( registries.getAttributeTypeRegistry().hasDescendants( node.getAttribute() ) )
170         {
171             // TODO check to see if descendant handling is necessary for the
172             // index so we can match properly even when for example a name
173             // attribute is used instead of more specific commonName
174             Iterator<AttributeType> descendants =
175                 registries.getAttributeTypeRegistry().descendants( node.getAttribute() );
176 
177             while ( descendants.hasNext() )
178             {
179                 AttributeType descendant = descendants.next();
180 
181                 attr = ( ServerAttribute ) entry.get( descendant );
182 
183                 //noinspection unchecked
184                 if ( attr != null && evaluate( ( IndexEntry<Object,ServerEntry> ) indexEntry, attr ) )
185                 {
186                     return true;
187                 }
188             }
189         }
190 
191         // we fell through so a match was not found - assertion was false.
192         return false;
193     }
194 
195 
196     public boolean evaluate( ServerEntry entry ) throws Exception
197     {
198         // get the attribute
199         ServerAttribute attr = ( ServerAttribute ) entry.get( type );
200 
201         // if the attribute does not exist just return false
202         if ( attr != null && evaluate( null, attr ) )
203         {
204             return true;
205         }
206 
207         // If we do not have the attribute, loop through the sub classes of
208         // the attributeType.  Perhaps the entry has an attribute value of a
209         // subtype (descendant) that will produce a match
210         if ( registries.getAttributeTypeRegistry().hasDescendants( node.getAttribute() ) )
211         {
212             // TODO check to see if descendant handling is necessary for the
213             // index so we can match properly even when for example a name
214             // attribute is used instead of more specific commonName
215             Iterator<AttributeType> descendants =
216                 registries.getAttributeTypeRegistry().descendants( node.getAttribute() );
217 
218             while ( descendants.hasNext() )
219             {
220                 AttributeType descendant = descendants.next();
221 
222                 attr = ( ServerAttribute ) entry.get( descendant );
223 
224                 if ( attr != null && evaluate( null, attr ) )
225                 {
226                     return true;
227                 }
228             }
229         }
230 
231         // we fell through so a match was not found - assertion was false.
232         return false;
233     }
234 
235 
236     // TODO - determine if comaparator and index entry should have the Value
237     // wrapper or the raw normalized value
238     private boolean evaluate( IndexEntry<Object,ServerEntry> indexEntry, ServerAttribute attribute ) throws Exception
239     {
240         /*
241          * Cycle through the attribute values testing normalized version
242          * obtained from using the ordering or equality matching rule's
243          * normalizer.  The test uses the comparator obtained from the
244          * appropriate matching rule to perform the check.
245          */
246         for ( Value value : attribute )
247         {
248             value.normalize( normalizer );
249 
250             //noinspection unchecked
251             if ( comparator.compare( value.getNormalizedValue(), node.getValue().getNormalizedValue() ) <= 0 )
252             {
253                 if ( indexEntry != null )
254                 {
255                     indexEntry.setValue( value.getNormalizedValue() );
256                 }
257                 return true;
258             }
259         }
260 
261         return false;
262     }
263 }