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.core.subtree;
21
22
23 import java.util.Iterator;
24
25 import javax.naming.Name;
26 import javax.naming.NamingException;
27
28 import org.apache.directory.server.core.entry.ServerEntry;
29 import org.apache.directory.server.core.event.Evaluator;
30 import org.apache.directory.server.core.event.ExpressionEvaluator;
31 import org.apache.directory.server.schema.registries.AttributeTypeRegistry;
32 import org.apache.directory.server.schema.registries.OidRegistry;
33 import org.apache.directory.shared.ldap.name.LdapDN;
34 import org.apache.directory.shared.ldap.subtree.SubtreeSpecification;
35 import org.apache.directory.shared.ldap.util.NamespaceTools;
36
37
38 /**
39 * An evaluator used to determine if an entry is included in the collection
40 * represented by a subtree specification.
41 *
42 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
43 * @version $Rev: 638228 $
44 */
45 public class SubtreeEvaluator
46 {
47 /** A refinement filter evaluator */
48 private final Evaluator evaluator;
49
50
51 /**
52 * Creates a subtreeSpecification evaluatior which can be used to determine
53 * if an entry is included within the collection of a subtree.
54 *
55 * @param oidRegistry a registry used to lookup objectClass names for OIDs
56 * @param attrRegistry registry to be looked up
57 * @throws NamingException
58 */
59 public SubtreeEvaluator( OidRegistry oidRegistry, AttributeTypeRegistry attrRegistry )
60 {
61 evaluator = new ExpressionEvaluator(oidRegistry, attrRegistry );
62 }
63
64
65 /**
66 * Determines if an entry is selected by a subtree specification.
67 *
68 * @param subtree the subtree specification
69 * @param apDn the distinguished name of the administrative point containing the subentry
70 * @param entryDn the distinguished name of the candidate entry
71 * @return true if the entry is selected by the specification, false if it is not
72 * @throws javax.naming.NamingException if errors are encountered while evaluating selection
73 */
74 public boolean evaluate( SubtreeSpecification subtree, Name apDn, Name entryDn, ServerEntry entry )
75 throws NamingException
76 {
77 // TODO: Try to make this cast unnecessary.
78 LdapDN entryLdapDn = (LdapDN) entryDn;
79
80 /* =====================================================================
81 * NOTE: Regarding the overall approach, we try to narrow down the
82 * possibilities by slowly pruning relative names off of the entryDn.
83 * For example we check first if the entry is a descendant of the AP.
84 * If so we use the relative name thereafter to calculate if it is
85 * a descendant of the base. This means shorter names to compare and
86 * less work to do while we continue to deduce inclusion by the subtree
87 * specification.
88 * =====================================================================
89 */
90
91 /*
92 * First we simply check if the candidate entry is a descendant of the
93 * administrative point. In the process we calculate the relative
94 * distinguished name relative to the administrative point.
95 */
96 Name apRelativeRdn;
97
98 if ( !NamespaceTools.isDescendant( apDn, entryDn ) )
99 {
100 return false;
101 }
102 else if ( apDn.equals( entryDn ) )
103 {
104 apRelativeRdn = new LdapDN();
105 }
106 else
107 {
108 apRelativeRdn = NamespaceTools.getRelativeName( apDn, entryDn );
109 }
110
111 /*
112 * We do the same thing with the base as we did with the administrative
113 * point: check if the entry is a descendant of the base and find the
114 * relative name of the entry with respect to the base rdn. With the
115 * baseRelativeRdn we can later make comparisons with specific exclusions.
116 */
117 Name baseRelativeRdn;
118
119 if ( subtree.getBase() != null && subtree.getBase().size() == 0 )
120 {
121 baseRelativeRdn = apRelativeRdn;
122 }
123 else if ( apRelativeRdn.equals( subtree.getBase() ) )
124 {
125 baseRelativeRdn = new LdapDN();
126 }
127 else if ( !NamespaceTools.isDescendant( subtree.getBase(), apRelativeRdn ) )
128 {
129 return false;
130 }
131 else
132 {
133 baseRelativeRdn = NamespaceTools.getRelativeName( subtree.getBase(), apRelativeRdn );
134 }
135
136 /*
137 * Evaluate based on minimum and maximum chop values. Here we simply
138 * need to compare the distances respectively with the size of the
139 * baseRelativeRdn. For the max distance entries with a baseRelativeRdn
140 * size greater than the max distance are rejected. For the min distance
141 * entries with a baseRelativeRdn size less than the minimum distance
142 * are rejected.
143 */
144 if ( subtree.getMaxBaseDistance() != SubtreeSpecification.UNBOUNDED_MAX )
145 {
146 if ( subtree.getMaxBaseDistance() < baseRelativeRdn.size() )
147 {
148 return false;
149 }
150 }
151
152 if ( subtree.getMinBaseDistance() > 0 )
153 {
154 if ( baseRelativeRdn.size() < subtree.getMinBaseDistance() )
155 {
156 return false;
157 }
158 }
159
160 /*
161 * For specific exclusions we must iterate through the set and check
162 * if the baseRelativeRdn is a descendant of the exclusion. The
163 * isDescendant() function will return true if the compared names
164 * are equal so for chopAfter exclusions we must check for equality
165 * as well and reject if the relative names are equal.
166 */
167 Iterator list = subtree.getChopBeforeExclusions().iterator();
168
169 while ( list.hasNext() )
170 {
171 Name chopBefore = ( Name ) list.next();
172
173 if ( NamespaceTools.isDescendant( chopBefore, baseRelativeRdn ) )
174 {
175 return false;
176 }
177 }
178
179 list = subtree.getChopAfterExclusions().iterator();
180
181 while ( list.hasNext() )
182 {
183 Name chopAfter = ( Name ) list.next();
184
185 if ( NamespaceTools.isDescendant( chopAfter, baseRelativeRdn ) && !chopAfter.equals( baseRelativeRdn ) )
186 {
187 return false;
188 }
189 }
190
191 /*
192 * The last remaining step is to check and see if the refinement filter
193 * selects the entry candidate based on objectClass attribute values.
194 * To do this we invoke the refinement evaluator members evaluate() method.
195 */
196 if ( subtree.getRefinement() != null )
197 {
198 return evaluator.evaluate( subtree.getRefinement(), entryLdapDn.toNormName(), entry );
199 }
200
201 /*
202 * If nothing has rejected the candidate entry and there is no refinement
203 * filter then the entry is included in the collection represented by the
204 * subtree specification so we return true.
205 */
206 return true;
207 }
208 }