1 /*
2 * Copyright [2006] [University Corporation for Advanced Internet Development, Inc.]
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.opensaml.xml.util;
18
19 import java.util.Collections;
20 import java.util.Map;
21 import java.util.Set;
22 import java.util.concurrent.ConcurrentHashMap;
23
24 import org.opensaml.xml.XMLObject;
25
26 /**
27 * Class which provides storage for the ID-to-XMLObject index mapping on an owning {@link org.opensaml.xml.XMLObject}.
28 */
29 public class IDIndex {
30
31 /** The XMLObject which owns this ID index. */
32 private XMLObject owner;
33
34 /** Mapping of ID attributes to XMLObjects in the subtree rooted at this object's owner.
35 * This allows constant-time dereferencing of ID-typed attributes within the subtree. */
36 private Map<String, XMLObject> idMappings;
37
38 /**
39 * Constructor.
40 *
41 * @param newOwner the XMLObject which owns this ID-to-XMLObject index
42 *
43 * @throws NullPointerException thrown if the given XMLObject is null
44 */
45 public IDIndex(XMLObject newOwner) throws NullPointerException {
46 if (newOwner == null) {
47 throw new NullPointerException("Attribute owner XMLObject may not be null");
48 }
49
50 owner = newOwner;
51 idMappings = new ConcurrentHashMap<String, XMLObject>();
52 }
53
54
55 /**
56 * Register an ID-to-XMLObject mapping for one of this object's owner's children.
57 *
58 * @param id the XMLObject child's ID attribute value
59 * @param referent the XMLObject child
60 */
61 public void registerIDMapping(String id, XMLObject referent) {
62 if (id == null) {
63 return;
64 }
65
66 idMappings.put(id, referent);
67 if (owner.hasParent()) {
68 owner.getParent().getIDIndex().registerIDMapping(id, referent);
69 }
70 }
71
72 /**
73 * Register multiple ID-to-XMLObject mappings for this object's owner's children.
74 *
75 * @param idIndex the ID-to-XMLObject mapping to register
76 */
77 public void registerIDMappings(IDIndex idIndex) {
78 if (idIndex == null || idIndex.isEmpty()) {
79 return;
80 }
81
82 idMappings.putAll(idIndex.getIDMappings());
83 if (owner.hasParent()) {
84 owner.getParent().getIDIndex().registerIDMappings(idIndex);
85 }
86 }
87
88 /**
89 * Deregister an ID-to-XMLObject mapping for one of this object's owner's children.
90 *
91 * @param id the ID attribute value of the XMLObject child to deregister
92 */
93 public void deregisterIDMapping(String id) {
94 if (id == null) {
95 return;
96 }
97
98 idMappings.remove(id);
99 if (owner.hasParent()) {
100 owner.getParent().getIDIndex().deregisterIDMapping(id);
101 }
102 }
103
104 /**
105 * Deregister multiple ID-to-XMLObject mappings for this object's owner's children.
106 *
107 * @param idIndex the ID-to-XMLObject mappings to deregister
108 */
109 public void deregisterIDMappings(IDIndex idIndex) {
110 if (idIndex == null || idIndex.isEmpty()) {
111 return;
112 }
113
114 for (String id : idIndex.getIDs()) {
115 idMappings.remove(id);
116 }
117 if (owner.hasParent()) {
118 owner.getParent().getIDIndex().deregisterIDMappings(idIndex);
119 }
120 }
121
122 /**
123 * Lookup and return the XMLObject identified by the specified ID attribute.
124 *
125 * @param id the ID attribute value to lookup
126 * @return the XMLObject identified by the ID attribute value
127 */
128 public XMLObject lookup(String id) {
129 return idMappings.get(id);
130 }
131
132 /**
133 * Return whether the index is currently empty.
134 *
135 * @return true if the index is currently empty
136 */
137 public boolean isEmpty() {
138 return idMappings.isEmpty();
139 }
140
141 /**
142 * Get the set of ID strings which are the index keys.
143 *
144 * @return the set of ID strings which are keys to the index
145 */
146 public Set<String> getIDs() {
147 return Collections.unmodifiableSet(idMappings.keySet());
148 }
149
150 /**
151 * Get the ID-to-XMLObject mappings for this object's object's owner's children.
152 *
153 * @return the ID-to-XMLObject mapping
154 */
155 protected Map<String, XMLObject> getIDMappings() {
156 return Collections.unmodifiableMap(idMappings);
157 }
158
159 }