LeafEvaluator


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.db;
18  
19  
20  import org.apache.ldap.common.NotImplementedException;
21  import org.apache.ldap.common.filter.*;
22  import org.apache.ldap.common.schema.AttributeType;
23  import org.apache.ldap.common.schema.MatchingRule;
24  import org.apache.ldap.common.schema.Normalizer;
25  import org.apache.ldap.server.schema.AttributeTypeRegistry;
26  import org.apache.ldap.server.schema.OidRegistry;
27  
28  import javax.naming.NamingEnumeration  ;
29  import javax.naming.NamingException  ;
30  import javax.naming.directory.Attribute  ;
31  import javax.naming.directory.Attributes  ;
32  import java.math.BigInteger  ;
33  import java.util.Comparator  ;
34  
35  
36  /**
37   * Evaluates LeafNode assertions on candidates using a database.
38   * 
39   * @author <a HREF="mailto:dev@directory.apache.org">Apache Directory Project</a>
40   * @version $Rev: 169198 $
41   */
42  public class LeafEvaluator implements Evaluator
43  {
44      /** equality matching type constant */
45      private static final int EQUALITY_MATCH = 0;
46      /** ordering matching type constant */
47      private static final int ORDERING_MATCH = 1;
48      /** substring matching type constant */
49      private static final int SUBSTRING_MATCH = 3;
50  
51  
52      /** Database used to evaluate leaf with */
53      private Database db;
54      /** Oid Registry used to translate attributeIds to OIDs */
55      private OidRegistry oidRegistry;
56      /** AttributeType registry needed for normalizing and comparing values */
57      private AttributeTypeRegistry attributeTypeRegistry;
58      /** Substring node evaluator we depend on */
59      private SubstringEvaluator substringEvaluator;
60      /** ScopeNode evaluator we depend on */
61      private ScopeEvaluator scopeEvaluator;
62  
63  
64      /**
65       * Creates a leaf expression node evaluator.
66       *
67       * @param db
68       * @param scopeEvaluator
69       * @param substringEvaluator
70       */
71      public LeafEvaluator( Database db, OidRegistry oidRegistry,
72                            AttributeTypeRegistry attributeTypeRegistry,
73                            ScopeEvaluator scopeEvaluator,
74                            SubstringEvaluator substringEvaluator )
75      {
76          this.db = db;
77          this.oidRegistry = oidRegistry;
78          this.attributeTypeRegistry = attributeTypeRegistry;
79          this.scopeEvaluator = scopeEvaluator;
80          this.substringEvaluator = substringEvaluator;
81      }
82  
83  
84      public ScopeEvaluator getScopeEvaluator()
85      {
86          return scopeEvaluator;
87      }
88  
89  
90      public SubstringEvaluator getSubstringEvaluator()
91      {
92          return substringEvaluator;
93      }
94  
95  
96      /**
97       * @see org.apache.ldap.server.db.Evaluator#evaluate(ExprNode, IndexRecord)
98       */
99      public boolean evaluate( ExprNode node, IndexRecord record ) throws NamingException  
100     {
101         if ( node instanceof ScopeNode )
102         {
103             return scopeEvaluator.evaluate( node, record );
104         }
105         
106         switch( ( ( LeafNode ) node ).getAssertionType() ) 
107         {
108         case( LeafNode.APPROXIMATE ):
109             return evalEquality( ( SimpleNode ) node, record );
110         case( LeafNode.EQUALITY ):
111             return evalEquality( ( SimpleNode ) node, record );
112         case( LeafNode.EXTENSIBLE ):
113             throw new NotImplementedException();
114         case( LeafNode.GREATEREQ ):
115             return evalGreater( ( SimpleNode ) node, record, true );
116         case( LeafNode.LESSEQ ):
117             return evalGreater( ( SimpleNode ) node, record, false );
118         case( LeafNode.PRESENCE ):
119             String   attrId = ( ( PresenceNode ) node ).getAttribute();
120             return evalPresence( attrId, record ); 
121         case( LeafNode.SUBSTRING ):
122             return substringEvaluator.evaluate( node, record );
123         default:
124             throw new NamingException  ( "Unrecognized leaf node type: "
125                 + ( ( LeafNode ) node ).getAssertionType() );
126         }
127     }
128     
129     
130     /**
131      * Evaluates a simple greater than or less than attribute value assertion on
132      * a perspective candidate.
133      * 
134      * @param node the greater than or less than node to evaluate
135      * @param record the IndexRecord of the perspective candidate
136      * @param isGreater true if it is a greater than or equal to comparison,
137      *      false if it is a less than or equal to comparison.
138      * @return the ava evaluation on the perspective candidate
139      * @throws NamingException if there is a database access failure
140      */
141     private boolean evalGreater( SimpleNode node, IndexRecord record,
142         boolean isGreater ) throws NamingException  
143     {
144         String   attrId = node.getAttribute();
145         BigInteger   id = record.getEntryId();
146         
147         if ( db.hasUserIndexOn( attrId ) )
148         {
149             Index idx = db.getUserIndex( attrId );
150             
151             if ( isGreater )
152             {
153                 return idx.hasValue( node.getValue(), id, true ); 
154             }
155             
156             return idx.hasValue( node.getValue(), id, false );
157         }
158         
159         // resusitate entry if need be
160         if ( null == record.getAttributes() )
161         {
162             record.setAttributes( db.lookup( id ) );
163         }
164         
165         // get the attribute associated with the node 
166         Attribute   attr = record.getAttributes().get( attrId );
167 
168         // If we do not have the attribute just return false
169         if ( null == attr )
170         {
171             return false;
172         }
173         
174         /*
175          * We need to iterate through all values and for each value we normalize
176          * and use the comparator to determine if a match exists.
177          */
178         Normalizer normalizer = getNormalizer( attrId );
179         Comparator   comparator = getComparator( attrId );
180         Object   filterValue = normalizer.normalize( node.getValue() );
181         NamingEnumeration   list = attr.getAll();
182         
183         /*
184          * Cheaper to not check isGreater in one loop - better to separate
185          * out into two loops which you choose to execute based on isGreater
186          */
187         if ( isGreater )
188         {
189             while ( list.hasMore() )
190             {
191                 Object   value = normalizer.normalize( list.next() );
192             
193                 // Found a value that is greater than or equal to the ava value
194                 if ( 0 >= comparator.compare( value, filterValue ) )
195                 {
196                     return true;
197                 }
198             }
199         }
200         else 
201         {    
202             while ( list.hasMore() )
203             {
204                 Object   value = normalizer.normalize( list.next() );
205             
206                 // Found a value that is less than or equal to the ava value
207                 if ( 0 <= comparator.compare( value, filterValue ) )
208                 {
209                     return true;
210                 }
211             }
212         }
213         
214         // no match so return false
215         return false;
216     }
217 
218     
219     /**
220      * Evaluates a simple presence attribute value assertion on a perspective
221      * candidate.
222      * 
223      * @param attrId the name of the attribute tested for presence 
224      * @param rec the IndexRecord of the perspective candidate
225      * @return the ava evaluation on the perspective candidate
226      * @throws NamingException if there is a database access failure
227      */
228     private boolean evalPresence( String   attrId, IndexRecord rec )
229         throws NamingException  
230     {
231         if ( db.hasUserIndexOn( attrId ) )
232         {
233             Index idx = db.getExistanceIndex();
234             return idx.hasValue( attrId, rec.getEntryId() );
235         }
236         
237         // resusitate entry if need be
238         if ( null == rec.getAttributes() )
239         {
240             rec.setAttributes( db.lookup( rec.getEntryId() ) );
241         }
242         
243         // get the attribute associated with the node 
244         Attributes   attrs = rec.getAttributes();
245 
246         if ( attrs == null )
247         {
248             return false;
249         }
250         
251         return null != attrs.get( attrId );
252     }
253 
254 
255     /**
256      * Evaluates a simple equality attribute value assertion on a perspective
257      * candidate.
258      *
259      * @param node the equality node to evaluate
260      * @param rec the IndexRecord of the perspective candidate
261      * @return the ava evaluation on the perspective candidate
262      * @throws NamingException if there is a database access failure
263      */
264     private boolean evalEquality( SimpleNode node, IndexRecord rec )
265         throws NamingException  
266     {
267         if ( db.hasUserIndexOn( node.getAttribute() ) )
268         {
269             Index idx = db.getUserIndex( node.getAttribute() );
270             return idx.hasValue( node.getValue(), rec.getEntryId() );
271         }
272 
273         Normalizer normalizer = getNormalizer( node.getAttribute() );
274         Comparator   comparator = getComparator( node.getAttribute() );
275 
276         /*
277          * Get the attribute and if it is not set in rec then resusitate it
278          * from the master table and set it in rec for use later if at all.
279          * Before iterating through all values for a match check to see if the
280          * AVA value is contained or the normalized form of the AVA value is 
281          * contained.
282          */
283         
284         // resusitate entry if need be
285         if ( null == rec.getAttributes() )
286         {
287             rec.setAttributes( db.lookup( rec.getEntryId() ) );
288         }
289         
290         // get the attribute associated with the node 
291         Attribute   attr = rec.getAttributes().get( node.getAttribute() );
292         
293         // If we do not have the attribute just return false
294         if ( null == attr )
295         {
296             return false;
297         }
298         
299         // check if AVA value exists in attribute
300         if ( attr.contains( node.getValue() ) )
301         {
302             return true;
303         }
304 
305         // get the normalized AVA filter value
306         Object   filterValue = normalizer.normalize( node.getValue() );
307 
308         // check if the normalized value is present
309         if ( attr.contains( filterValue ) )
310         {
311             return true;
312         }
313         
314         /*
315          * We need to now iterate through all values because we could not get
316          * a lookup to work.  For each value we normalize and use the comparator
317          * to determine if a match exists.
318          */
319         NamingEnumeration   list = attr.getAll();
320         while ( list.hasMore() )
321         {
322             Object   value = normalizer.normalize( list.next() );
323             
324             if ( 0 == comparator.compare( value, filterValue ) )
325             {
326                 return true;
327             }
328         }
329         
330         // no match so return false
331         return false;
332     }
333 
334 
335     /**
336      * Gets the comparator for equality matching.
337      *
338      * @param attrId the attribute identifier
339      * @return the comparator for equality matching
340      * @throws NamingException if there is a failure
341      */
342     private Comparator   getComparator( String   attrId ) throws NamingException  
343     {
344         MatchingRule mrule = getMatchingRule( attrId, EQUALITY_MATCH );
345         return mrule.getComparator();
346     }
347 
348 
349     /**
350      * Gets the normalizer for equality matching.
351      *
352      * @param attrId the attribute identifier
353      * @return the normalizer for equality matching
354      * @throws NamingException if there is a failure
355      */
356     private Normalizer getNormalizer( String   attrId ) throws NamingException  
357     {
358         MatchingRule mrule = getMatchingRule( attrId, EQUALITY_MATCH );
359         return mrule.getNormalizer();
360     }
361 
362 
363     /**
364      * Gets the matching rule for an attributeType.
365      *
366      * @param attrId the attribute identifier
367      * @return the matching rule
368      * @throws NamingException if there is a failure
369      */
370     private MatchingRule getMatchingRule( String   attrId, int matchType )
371         throws NamingException  
372     {
373         MatchingRule mrule = null;
374         String   oid = oidRegistry.getOid( attrId );
375         AttributeType type = attributeTypeRegistry.lookup( oid );
376 
377         switch( matchType )
378         {
379             case( EQUALITY_MATCH ):
380                 mrule = type.getEquality();
381                 break;
382             case( SUBSTRING_MATCH ):
383                 mrule = type.getSubstr();
384                 break;
385             case( ORDERING_MATCH ):
386                 mrule = type.getOrdering();
387                 break;
388             default:
389                 throw new NamingException  ( "Unknown match type: " + matchType );
390         }
391 
392         return mrule;
393     }
394 }
395
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