1 /*
2 * Copyright 1999-2004 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package javax.naming.directory;
27
28 import java.util.Vector;
29 import java.util.Enumeration;
30 import java.util.NoSuchElementException;
31 import java.lang.reflect.Array;
32
33 import javax.naming.NamingException;
34 import javax.naming.NamingEnumeration;
35 import javax.naming.OperationNotSupportedException;
36
37 /**
38 * This class provides a basic implementation of the <tt>Attribute</tt> interface.
39 *<p>
40 * This implementation does not support the schema methods
41 * <tt>getAttributeDefinition()</tt> and <tt>getAttributeSyntaxDefinition()</tt>.
42 * They simply throw <tt>OperationNotSupportedException</tt>.
43 * Subclasses of <tt>BasicAttribute</tt> should override these methods if they
44 * support them.
45 *<p>
46 * The <tt>BasicAttribute</tt> class by default uses <tt>Object.equals()</tt> to
47 * determine equality of attribute values when testing for equality or
48 * when searching for values, <em>except</em> when the value is an array.
49 * For an array, each element of the array is checked using <tt>Object.equals()</tt>.
50 * Subclasses of <tt>BasicAttribute</tt> can make use of schema information
51 * when doing similar equality checks by overriding methods
52 * in which such use of schema is meaningful.
53 * Similarly, the <tt>BasicAttribute</tt> class by default returns the values passed to its
54 * constructor and/or manipulated using the add/remove methods.
55 * Subclasses of <tt>BasicAttribute</tt> can override <tt>get()</tt> and <tt>getAll()</tt>
56 * to get the values dynamically from the directory (or implement
57 * the <tt>Attribute</tt> interface directly instead of subclassing <tt>BasicAttribute</tt>).
58 *<p>
59 * Note that updates to <tt>BasicAttribute</tt> (such as adding or removing a value)
60 * does not affect the corresponding representation of the attribute
61 * in the directory. Updates to the directory can only be effected
62 * using operations in the <tt>DirContext</tt> interface.
63 *<p>
64 * A <tt>BasicAttribute</tt> instance is not synchronized against concurrent
65 * multithreaded access. Multiple threads trying to access and modify a
66 * <tt>BasicAttribute</tt> should lock the object.
67 *
68 * @author Rosanna Lee
69 * @author Scott Seligman
70 * @since 1.3
71 */
72 public class BasicAttribute implements Attribute {
73 /**
74 * Holds the attribute's id. It is initialized by the public constructor and
75 * cannot be null unless methods in BasicAttribute that use attrID
76 * have been overridden.
77 * @serial
78 */
79 protected String attrID;
80
81 /**
82 * Holds the attribute's values. Initialized by public constructors.
83 * Cannot be null unless methods in BasicAttribute that use
84 * values have been overridden.
85 */
86 protected transient Vector<Object> values;
87
88 /**
89 * A flag for recording whether this attribute's values are ordered.
90 * @serial
91 */
92 protected boolean ordered = false;
93
94 public Object clone() {
95 BasicAttribute attr;
96 try {
97 attr = (BasicAttribute)super.clone();
98 } catch (CloneNotSupportedException e) {
99 attr = new BasicAttribute(attrID, ordered);
100 }
101 attr.values = (Vector)values.clone();
102 return attr;
103 }
104
105 /**
106 * Determines whether obj is equal to this attribute.
107 * Two attributes are equal if their attribute-ids, syntaxes
108 * and values are equal.
109 * If the attribute values are unordered, the order that the values were added
110 * are irrelevant. If the attribute values are ordered, then the
111 * order the values must match.
112 * If obj is null or not an Attribute, false is returned.
113 *<p>
114 * By default <tt>Object.equals()</tt> is used when comparing the attribute
115 * id and its values except when a value is an array. For an array,
116 * each element of the array is checked using <tt>Object.equals()</tt>.
117 * A subclass may override this to make
118 * use of schema syntax information and matching rules,
119 * which define what it means for two attributes to be equal.
120 * How and whether a subclass makes
121 * use of the schema information is determined by the subclass.
122 * If a subclass overrides <tt>equals()</tt>, it should also override
123 * <tt>hashCode()</tt>
124 * such that two attributes that are equal have the same hash code.
125 *
126 * @param obj The possibly null object to check.
127 * @return true if obj is equal to this attribute; false otherwise.
128 * @see #hashCode
129 * @see #contains
130 */
131 public boolean equals(Object obj) {
132 if ((obj != null) && (obj instanceof Attribute)) {
133 Attribute target = (Attribute)obj;
134
135 // Check order first
136 if (isOrdered() != target.isOrdered()) {
137 return false;
138 }
139 int len;
140 if (attrID.equals(target.getID()) &&
141 (len=size()) == target.size()) {
142 try {
143 if (isOrdered()) {
144 // Go through both list of values
145 for (int i = 0; i < len; i++) {
146 if (!valueEquals(get(i), target.get(i))) {
147 return false;
148 }
149 }
150 } else {
151 // order is not relevant; check for existence
152 Enumeration theirs = target.getAll();
153 while (theirs.hasMoreElements()) {
154 if (find(theirs.nextElement()) < 0)
155 return false;
156 }
157 }
158 } catch (NamingException e) {
159 return false;
160 }
161 return true;
162 }
163 }
164 return false;
165 }
166
167 /**
168 * Calculates the hash code of this attribute.
169 *<p>
170 * The hash code is computed by adding the hash code of
171 * the attribute's id and that of all of its values except for
172 * values that are arrays.
173 * For an array, the hash code of each element of the array is summed.
174 * If a subclass overrides <tt>hashCode()</tt>, it should override
175 * <tt>equals()</tt>
176 * as well so that two attributes that are equal have the same hash code.
177 *
178 * @return an int representing the hash code of this attribute.
179 * @see #equals
180 */
181 public int hashCode() {
182 int hash = attrID.hashCode();
183 int num = values.size();
184 Object val;
185 for (int i = 0; i < num; i ++) {
186 val = values.elementAt(i);
187 if (val != null) {
188 if (val.getClass().isArray()) {
189 Object it;
190 int len = Array.getLength(val);
191 for (int j = 0 ; j < len ; j++) {
192 it = Array.get(val, j);
193 if (it != null) {
194 hash += it.hashCode();
195 }
196 }
197 } else {
198 hash += val.hashCode();
199 }
200 }
201 }
202 return hash;
203 }
204
205 /**
206 * Generates the string representation of this attribute.
207 * The string consists of the attribute's id and its values.
208 * This string is meant for debugging and not meant to be
209 * interpreted programmatically.
210 * @return The non-null string representation of this attribute.
211 */
212 public String toString() {
213 StringBuffer answer = new StringBuffer(attrID + ": ");
214 if (values.size() == 0) {
215 answer.append("No values");
216 } else {
217 boolean start = true;
218 for (Enumeration e = values.elements(); e.hasMoreElements(); ) {
219 if (!start)
220 answer.append(", ");
221 answer.append(e.nextElement());
222 start = false;
223 }
224 }
225 return answer.toString();
226 }
227
228 /**
229 * Constructs a new instance of an unordered attribute with no value.
230 *
231 * @param id The attribute's id. It cannot be null.
232 */
233 public BasicAttribute(String id) {
234 this(id, false);
235 }
236
237 /**
238 * Constructs a new instance of an unordered attribute with a single value.
239 *
240 * @param id The attribute's id. It cannot be null.
241 * @param value The attribute's value. If null, a null
242 * value is added to the attribute.
243 */
244 public BasicAttribute(String id, Object value) {
245 this(id, value, false);
246 }
247
248 /**
249 * Constructs a new instance of a possibly ordered attribute with no value.
250 *
251 * @param id The attribute's id. It cannot be null.
252 * @param ordered true means the attribute's values will be ordered;
253 * false otherwise.
254 */
255 public BasicAttribute(String id, boolean ordered) {
256 attrID = id;
257 values = new Vector();
258 this.ordered = ordered;
259 }
260
261 /**
262 * Constructs a new instance of a possibly ordered attribute with a
263 * single value.
264 *
265 * @param id The attribute's id. It cannot be null.
266 * @param value The attribute's value. If null, a null
267 * value is added to the attribute.
268 * @param ordered true means the attribute's values will be ordered;
269 * false otherwise.
270 */
271 public BasicAttribute(String id, Object value, boolean ordered) {
272 this(id, ordered);
273 values.addElement(value);
274 }
275
276 /**
277 * Retrieves an enumeration of this attribute's values.
278 *<p>
279 * By default, the values returned are those passed to the
280 * constructor and/or manipulated using the add/replace/remove methods.
281 * A subclass may override this to retrieve the values dynamically
282 * from the directory.
283 */
284 public NamingEnumeration<?> getAll() throws NamingException {
285 return new ValuesEnumImpl();
286 }
287
288 /**
289 * Retrieves one of this attribute's values.
290 *<p>
291 * By default, the value returned is one of those passed to the
292 * constructor and/or manipulated using the add/replace/remove methods.
293 * A subclass may override this to retrieve the value dynamically
294 * from the directory.
295 */
296 public Object get() throws NamingException {
297 if (values.size() == 0) {
298 throw new
299 NoSuchElementException("Attribute " + getID() + " has no value");
300 } else {
301 return values.elementAt(0);
302 }
303 }
304
305 public int size() {
306 return values.size();
307 }
308
309 public String getID() {
310 return attrID;
311 }
312
313 /**
314 * Determines whether a value is in this attribute.
315 *<p>
316 * By default,
317 * <tt>Object.equals()</tt> is used when comparing <tt>attrVal</tt>
318 * with this attribute's values except when <tt>attrVal</tt> is an array.
319 * For an array, each element of the array is checked using
320 * <tt>Object.equals()</tt>.
321 * A subclass may use schema information to determine equality.
322 */
323 public boolean contains(Object attrVal) {
324 return (find(attrVal) >= 0);
325 }
326
327 // For finding first element that has a null in JDK1.1 Vector.
328 // In the Java 2 platform, can just replace this with Vector.indexOf(target);
329 private int find(Object target) {
330 Class cl;
331 if (target == null) {
332 int ct = values.size();
333 for (int i = 0 ; i < ct ; i++) {
334 if (values.elementAt(i) == null)
335 return i;
336 }
337 } else if ((cl=target.getClass()).isArray()) {
338 int ct = values.size();
339 Object it;
340 for (int i = 0 ; i < ct ; i++) {
341 it = values.elementAt(i);
342 if (it != null && cl == it.getClass()
343 && arrayEquals(target, it))
344 return i;
345 }
346 } else {
347 return values.indexOf(target, 0);
348 }
349 return -1; // not found
350 }
351
352 /**
353 * Determines whether two attribute values are equal.
354 * Use arrayEquals for arrays and <tt>Object.equals()</tt> otherwise.
355 */
356 private static boolean valueEquals(Object obj1, Object obj2) {
357 if (obj1 == obj2) {
358 return true; // object references are equal
359 }
360 if (obj1 == null) {
361 return false; // obj2 was not false
362 }
363 if (obj1.getClass().isArray() &&
364 obj2.getClass().isArray()) {
365 return arrayEquals(obj1, obj2);
366 }
367 return (obj1.equals(obj2));
368 }
369
370 /**
371 * Determines whether two arrays are equal by comparing each of their
372 * elements using <tt>Object.equals()</tt>.
373 */
374 private static boolean arrayEquals(Object a1, Object a2) {
375 int len;
376 if ((len = Array.getLength(a1)) != Array.getLength(a2))
377 return false;
378
379 for (int j = 0; j < len; j++) {
380 Object i1 = Array.get(a1, j);
381 Object i2 = Array.get(a2, j);
382 if (i1 == null || i2 == null) {
383 if (i1 != i2)
384 return false;
385 } else if (!i1.equals(i2)) {
386 return false;
387 }
388 }
389 return true;
390 }
391
392 /**
393 * Adds a new value to this attribute.
394 *<p>
395 * By default, <tt>Object.equals()</tt> is used when comparing <tt>attrVal</tt>
396 * with this attribute's values except when <tt>attrVal</tt> is an array.
397 * For an array, each element of the array is checked using
398 * <tt>Object.equals()</tt>.
399 * A subclass may use schema information to determine equality.
400 */
401 public boolean add(Object attrVal) {
402 if (isOrdered() || (find(attrVal) < 0)) {
403 values.addElement(attrVal);
404 return true;
405 } else {
406 return false;
407 }
408 }
409
410 /**
411 * Removes a specified value from this attribute.
412 *<p>
413 * By default, <tt>Object.equals()</tt> is used when comparing <tt>attrVal</tt>
414 * with this attribute's values except when <tt>attrVal</tt> is an array.
415 * For an array, each element of the array is checked using
416 * <tt>Object.equals()</tt>.
417 * A subclass may use schema information to determine equality.
418 */
419 public boolean remove(Object attrval) {
420 // For the Java 2 platform, can just use "return removeElement(attrval);"
421 // Need to do the following to handle null case
422
423 int i = find(attrval);
424 if (i >= 0) {
425 values.removeElementAt(i);
426 return true;
427 }
428 return false;
429 }
430
431 public void clear() {
432 values.setSize(0);
433 }
434
435 // ---- ordering methods
436
437 public boolean isOrdered() {
438 return ordered;
439 }
440
441 public Object get(int ix) throws NamingException {
442 return values.elementAt(ix);
443 }
444
445 public Object remove(int ix) {
446 Object answer = values.elementAt(ix);
447 values.removeElementAt(ix);
448 return answer;
449 }
450
451 public void add(int ix, Object attrVal) {
452 if (!isOrdered() && contains(attrVal)) {
453 throw new IllegalStateException(
454 "Cannot add duplicate to unordered attribute");
455 }
456 values.insertElementAt(attrVal, ix);
457 }
458
459 public Object set(int ix, Object attrVal) {
460 if (!isOrdered() && contains(attrVal)) {
461 throw new IllegalStateException(
462 "Cannot add duplicate to unordered attribute");
463 }
464
465 Object answer = values.elementAt(ix);
466 values.setElementAt(attrVal, ix);
467 return answer;
468 }
469
470 // ----------------- Schema methods
471
472 /**
473 * Retrieves the syntax definition associated with this attribute.
474 *<p>
475 * This method by default throws OperationNotSupportedException. A subclass
476 * should override this method if it supports schema.
477 */
478 public DirContext getAttributeSyntaxDefinition() throws NamingException {
479 throw new OperationNotSupportedException("attribute syntax");
480 }
481
482 /**
483 * Retrieves this attribute's schema definition.
484 *<p>
485 * This method by default throws OperationNotSupportedException. A subclass
486 * should override this method if it supports schema.
487 */
488 public DirContext getAttributeDefinition() throws NamingException {
489 throw new OperationNotSupportedException("attribute definition");
490 }
491
492
493 // ---- serialization methods
494
495 /**
496 * Overridden to avoid exposing implementation details
497 * @serialData Default field (the attribute ID -- a String),
498 * followed by the number of values (an int), and the
499 * individual values.
500 */
501 private void writeObject(java.io.ObjectOutputStream s)
502 throws java.io.IOException {
503 s.defaultWriteObject(); // write out the attrID
504 s.writeInt(values.size());
505 for (int i = 0; i < values.size(); i++) {
506 s.writeObject(values.elementAt(i));
507 }
508 }
509
510 /**
511 * Overridden to avoid exposing implementation details.
512 */
513 private void readObject(java.io.ObjectInputStream s)
514 throws java.io.IOException, ClassNotFoundException {
515 s.defaultReadObject(); // read in the attrID
516 int n = s.readInt(); // number of values
517 values = new Vector(n);
518 while (--n >= 0) {
519 values.addElement(s.readObject());
520 }
521 }
522
523
524 class ValuesEnumImpl implements NamingEnumeration<Object> {
525 Enumeration list;
526
527 ValuesEnumImpl() {
528 list = values.elements();
529 }
530
531 public boolean hasMoreElements() {
532 return list.hasMoreElements();
533 }
534
535 public Object nextElement() {
536 return(list.nextElement());
537 }
538
539 public Object next() throws NamingException {
540 return list.nextElement();
541 }
542
543 public boolean hasMore() throws NamingException {
544 return list.hasMoreElements();
545 }
546
547 public void close() throws NamingException {
548 list = null;
549 }
550 }
551
552 /**
553 * Use serialVersionUID from JNDI 1.1.1 for interoperability.
554 */
555 private static final long serialVersionUID = 6743528196119291326L;
556 }
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