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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.GreaterEqNode;
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 GreaterEqNode
42   * assertions.
43   *
44   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
45   * @version $Rev$
46   */
47  public class GreaterEqEvaluator implements Evaluator<GreaterEqNode, ServerEntry>
48  {
49      private final GreaterEqNode 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 GreaterEqEvaluator( GreaterEqNode 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 GreaterEqNode evaluation: " + node );
93          }
94  
95          normalizer = mr.getNormalizer();
96          comparator = mr.getComparator();
97      }
98  
99  
100     public GreaterEqNode 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( IndexEntry<?,ServerEntry> indexEntry ) throws Exception
125     {
126         if ( idx != null )
127         {
128             return idx.reverseGreaterOrEq( indexEntry.getId(), node.getValue().get() );
129         }
130 
131         ServerEntry entry = indexEntry.getObject();
132 
133         // resuscitate the entry if it has not been and set entry in IndexEntry
134         if ( null == entry )
135         {
136             entry = db.lookup( indexEntry.getId() );
137             indexEntry.setObject( entry );
138         }
139 
140         /*
141          * The code below could have been replaced by a call to
142          * evaluate( ServerEntry ) but it was not because we wanted to make
143          * sure the call to evaluate with the attribute was made using a
144          * non-null IndexEntry parameter.  This is to make sure the call to
145          * evaluate with the attribute will set the value on the IndexEntry.
146          */
147 
148         // get the attribute
149         ServerAttribute attr = ( ServerAttribute ) entry.get( type );
150 
151         // if the attribute exists and has a greater than or equal value return true
152         //noinspection unchecked
153         if ( attr != null && evaluate( ( IndexEntry<Object,ServerEntry> ) indexEntry, attr ) )
154         {
155             return true;
156         }
157 
158         // If we do not have the attribute, loop through the sub classes of
159         // the attributeType.  Perhaps the entry has an attribute value of a
160         // subtype (descendant) that will produce a match
161         if ( registries.getAttributeTypeRegistry().hasDescendants( node.getAttribute() ) )
162         {
163             // TODO check to see if descendant handling is necessary for the
164             // index so we can match properly even when for example a name
165             // attribute is used instead of more specific commonName
166             Iterator<AttributeType> descendants =
167                 registries.getAttributeTypeRegistry().descendants( node.getAttribute() );
168 
169             while ( descendants.hasNext() )
170             {
171                 AttributeType descendant = descendants.next();
172 
173                 attr = ( ServerAttribute ) entry.get( descendant );
174 
175                 //noinspection unchecked
176                 if ( attr != null && evaluate( ( IndexEntry<Object, ServerEntry> ) indexEntry, attr ) )
177                 {
178                     return true;
179                 }
180             }
181         }
182 
183         // we fell through so a match was not found - assertion was false.
184         return false;
185     }
186 
187 
188     public boolean evaluate( Long id ) throws Exception
189     {
190         if ( idx != null )
191         {
192             return idx.reverseGreaterOrEq( id, node.getValue().get() );
193         }
194 
195         return evaluate ( db.lookup( id ) );
196     }
197 
198 
199     public boolean evaluate( ServerEntry entry ) throws Exception
200     {
201         // get the attribute
202         ServerAttribute attr = ( ServerAttribute ) entry.get( type );
203 
204         // if the attribute exists and has a greater than or equal value return true
205         if ( attr != null && evaluate( null, attr ) )
206         {
207             return true;
208         }
209 
210         // If we do not have the attribute, loop through the sub classes of
211         // the attributeType.  Perhaps the entry has an attribute value of a
212         // subtype (descendant) that will produce a match
213         if ( registries.getAttributeTypeRegistry().hasDescendants( node.getAttribute() ) )
214         {
215             // TODO check to see if descendant handling is necessary for the
216             // index so we can match properly even when for example a name
217             // attribute is used instead of more specific commonName
218             Iterator<AttributeType> descendants =
219                 registries.getAttributeTypeRegistry().descendants( node.getAttribute() );
220 
221             while ( descendants.hasNext() )
222             {
223                 AttributeType descendant = descendants.next();
224 
225                 attr = ( ServerAttribute ) entry.get( descendant );
226 
227                 if ( attr != null && evaluate( null, attr ) )
228                 {
229                     return true;
230                 }
231             }
232         }
233 
234         // we fell through so a match was not found - assertion was false.
235         return false;
236     }
237 
238 
239     // TODO - determine if comaparator and index entry should have the Value
240     // wrapper or the raw normalized value 
241     private boolean evaluate( IndexEntry<Object,ServerEntry> indexEntry, ServerAttribute attribute ) throws Exception
242     {
243         /*
244          * Cycle through the attribute values testing normalized version
245          * obtained from using the ordering or equality matching rule's
246          * normalizer.  The test uses the comparator obtained from the
247          * appropriate matching rule to perform the check.
248          */
249         for ( Value value : attribute )
250         {
251             value.normalize( normalizer );
252 
253             //noinspection unchecked
254             if ( comparator.compare( value.getNormalizedValue(), node.getValue().getNormalizedValue() ) >= 0 )
255             {
256                 if ( indexEntry != null )
257                 {
258                     indexEntry.setValue( value.getNormalizedValue() );
259                 }
260                 return true;
261             }
262         }
263 
264         return false;
265     }
266 }