1 /*
2 * Copyright 2000-2007 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
27 package javax.management.openmbean;
28
29
30 // java import
31 //
32 import java.util.ArrayList;
33 import java.util.Collections;
34 import java.util.Iterator;
35 import java.util.List;
36
37 // jmx import
38 //
39
40
41 /**
42 * The <code>TabularType</code> class is the <i> open type</i> class
43 * whose instances describe the types of {@link TabularData <code>TabularData</code>} values.
44 *
45 * @since 1.5
46 */
47 public class TabularType extends OpenType<TabularData> {
48
49 /* Serial version */
50 static final long serialVersionUID = 6554071860220659261L;
51
52
53 /**
54 * @serial The composite type of rows
55 */
56 private CompositeType rowType;
57
58 /**
59 * @serial The items used to index each row element, kept in the order the user gave
60 * This is an unmodifiable {@link ArrayList}
61 */
62 private List<String> indexNames;
63
64
65 private transient Integer myHashCode = null; // As this instance is immutable, these two values
66 private transient String myToString = null; // need only be calculated once.
67
68
69 /* *** Constructor *** */
70
71 /**
72 * Constructs a <code>TabularType</code> instance, checking for the validity of the given parameters.
73 * The validity constraints are described below for each parameter.
74 * <p>
75 * The Java class name of tabular data values this tabular type represents
76 * (ie the class name returned by the {@link OpenType#getClassName() getClassName} method)
77 * is set to the string value returned by <code>TabularData.class.getName()</code>.
78 * <p>
79 * @param typeName The name given to the tabular type this instance represents; cannot be a null or empty string.
80 * <br>
81 * @param description The human readable description of the tabular type this instance represents;
82 * cannot be a null or empty string.
83 * <br>
84 * @param rowType The type of the row elements of tabular data values described by this tabular type instance;
85 * cannot be null.
86 * <br>
87 * @param indexNames The names of the items the values of which are used to uniquely index each row element in the
88 * tabular data values described by this tabular type instance;
89 * cannot be null or empty. Each element should be an item name defined in <var>rowType</var>
90 * (no null or empty string allowed).
91 * It is important to note that the <b>order</b> of the item names in <var>indexNames</var>
92 * is used by the methods {@link TabularData#get(java.lang.Object[]) <code>get</code>} and
93 * {@link TabularData#remove(java.lang.Object[]) <code>remove</code>} of class
94 * <code>TabularData</code> to match their array of values parameter to items.
95 * <br>
96 * @throws IllegalArgumentException if <var>rowType</var> is null,
97 * or <var>indexNames</var> is a null or empty array,
98 * or an element in <var>indexNames</var> is a null or empty string,
99 * or <var>typeName</var> or <var>description</var> is a null or empty string.
100 * <br>
101 * @throws OpenDataException if an element's value of <var>indexNames</var>
102 * is not an item name defined in <var>rowType</var>.
103 */
104 public TabularType(String typeName,
105 String description,
106 CompositeType rowType,
107 String[] indexNames) throws OpenDataException {
108
109 // Check and initialize state defined by parent.
110 //
111 super(TabularData.class.getName(), typeName, description, false);
112
113 // Check rowType is not null
114 //
115 if (rowType == null) {
116 throw new IllegalArgumentException("Argument rowType cannot be null.");
117 }
118
119 // Check indexNames is neither null nor empty and does not contain any null element or empty string
120 //
121 checkForNullElement(indexNames, "indexNames");
122 checkForEmptyString(indexNames, "indexNames");
123
124 // Check all indexNames values are valid item names for rowType
125 //
126 for (int i=0; i<indexNames.length; i++) {
127 if ( ! rowType.containsKey(indexNames[i]) ) {
128 throw new OpenDataException("Argument's element value indexNames["+ i +"]=\""+ indexNames[i] +
129 "\" is not a valid item name for rowType.");
130 }
131 }
132
133 // initialize rowType
134 //
135 this.rowType = rowType;
136
137 // initialize indexNames (copy content so that subsequent
138 // modifs to the array referenced by the indexNames parameter
139 // have no impact)
140 //
141 List<String> tmpList = new ArrayList<String>(indexNames.length + 1);
142 for (int i=0; i<indexNames.length; i++) {
143 tmpList.add(indexNames[i]);
144 }
145 this.indexNames = Collections.unmodifiableList(tmpList);
146 }
147
148 /**
149 * Checks that Object[] arg is neither null nor empty (ie length==0)
150 * and that it does not contain any null element.
151 */
152 private static void checkForNullElement(Object[] arg, String argName) {
153 if ( (arg == null) || (arg.length == 0) ) {
154 throw new IllegalArgumentException("Argument "+ argName +"[] cannot be null or empty.");
155 }
156 for (int i=0; i<arg.length; i++) {
157 if (arg[i] == null) {
158 throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be null.");
159 }
160 }
161 }
162
163 /**
164 * Checks that String[] does not contain any empty (or blank characters only) string.
165 */
166 private static void checkForEmptyString(String[] arg, String argName) {
167 for (int i=0; i<arg.length; i++) {
168 if (arg[i].trim().equals("")) {
169 throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be an empty string.");
170 }
171 }
172 }
173
174
175 /* *** Tabular type specific information methods *** */
176
177 /**
178 * Returns the type of the row elements of tabular data values
179 * described by this <code>TabularType</code> instance.
180 *
181 * @return the type of each row.
182 */
183 public CompositeType getRowType() {
184
185 return rowType;
186 }
187
188 /**
189 * <p>Returns, in the same order as was given to this instance's
190 * constructor, an unmodifiable List of the names of the items the
191 * values of which are used to uniquely index each row element of
192 * tabular data values described by this <code>TabularType</code>
193 * instance.</p>
194 *
195 * @return a List of String representing the names of the index
196 * items.
197 *
198 */
199 public List<String> getIndexNames() {
200
201 return indexNames;
202 }
203
204 /**
205 * Tests whether <var>obj</var> is a value which could be
206 * described by this <code>TabularType</code> instance.
207 *
208 * <p>If <var>obj</var> is null or is not an instance of
209 * <code>javax.management.openmbean.TabularData</code>,
210 * <code>isValue</code> returns <code>false</code>.</p>
211 *
212 * <p>If <var>obj</var> is an instance of
213 * <code>javax.management.openmbean.TabularData</code>, say {@code
214 * td}, the result is true if this {@code TabularType} is
215 * <em>assignable from</em> {@link TabularData#getTabularType()
216 * td.getTabularType()}, as defined in {@link
217 * CompositeType#isValue CompositeType.isValue}.</p>
218 *
219 * @param obj the value whose open type is to be tested for
220 * compatibility with this <code>TabularType</code> instance.
221 *
222 * @return <code>true</code> if <var>obj</var> is a value for this
223 * tabular type, <code>false</code> otherwise.
224 */
225 public boolean isValue(Object obj) {
226
227 // if obj is null or not a TabularData, return false
228 //
229 if (!(obj instanceof TabularData))
230 return false;
231
232 // if obj is not a TabularData, return false
233 //
234 TabularData value = (TabularData) obj;
235 TabularType valueType = value.getTabularType();
236 return isAssignableFrom(valueType);
237 }
238
239 @Override
240 boolean isAssignableFrom(OpenType ot) {
241 if (!(ot instanceof TabularType))
242 return false;
243 TabularType tt = (TabularType) ot;
244 if (!getTypeName().equals(tt.getTypeName()) ||
245 !getIndexNames().equals(tt.getIndexNames()))
246 return false;
247 return getRowType().isAssignableFrom(tt.getRowType());
248 }
249
250
251 /* *** Methods overriden from class Object *** */
252
253 /**
254 * Compares the specified <code>obj</code> parameter with this <code>TabularType</code> instance for equality.
255 * <p>
256 * Two <code>TabularType</code> instances are equal if and only if all of the following statements are true:
257 * <ul>
258 * <li>their type names are equal</li>
259 * <li>their row types are equal</li>
260 * <li>they use the same index names, in the same order</li>
261 * </ul>
262 * <br>
263 * @param obj the object to be compared for equality with this <code>TabularType</code> instance;
264 * if <var>obj</var> is <code>null</code>, <code>equals</code> returns <code>false</code>.
265 *
266 * @return <code>true</code> if the specified object is equal to this <code>TabularType</code> instance.
267 */
268 public boolean equals(Object obj) {
269
270 // if obj is null, return false
271 //
272 if (obj == null) {
273 return false;
274 }
275
276 // if obj is not a TabularType, return false
277 //
278 TabularType other;
279 try {
280 other = (TabularType) obj;
281 } catch (ClassCastException e) {
282 return false;
283 }
284
285 // Now, really test for equality between this TabularType instance and the other:
286 //
287
288 // their names should be equal
289 if ( ! this.getTypeName().equals(other.getTypeName()) ) {
290 return false;
291 }
292
293 // their row types should be equal
294 if ( ! this.rowType.equals(other.rowType) ) {
295 return false;
296 }
297
298 // their index names should be equal and in the same order (ensured by List.equals())
299 if ( ! this.indexNames.equals(other.indexNames) ) {
300 return false;
301 }
302
303 // All tests for equality were successfull
304 //
305 return true;
306 }
307
308 /**
309 * Returns the hash code value for this <code>TabularType</code> instance.
310 * <p>
311 * The hash code of a <code>TabularType</code> instance is the sum of the hash codes
312 * of all elements of information used in <code>equals</code> comparisons
313 * (ie: name, row type, index names).
314 * This ensures that <code> t1.equals(t2) </code> implies that <code> t1.hashCode()==t2.hashCode() </code>
315 * for any two <code>TabularType</code> instances <code>t1</code> and <code>t2</code>,
316 * as required by the general contract of the method
317 * {@link Object#hashCode() Object.hashCode()}.
318 * <p>
319 * As <code>TabularType</code> instances are immutable, the hash code for this instance is calculated once,
320 * on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.
321 *
322 * @return the hash code value for this <code>TabularType</code> instance
323 */
324 public int hashCode() {
325
326 // Calculate the hash code value if it has not yet been done (ie 1st call to hashCode())
327 //
328 if (myHashCode == null) {
329 int value = 0;
330 value += this.getTypeName().hashCode();
331 value += this.rowType.hashCode();
332 for (Iterator k = indexNames.iterator(); k.hasNext(); ) {
333 value += k.next().hashCode();
334 }
335 myHashCode = Integer.valueOf(value);
336 }
337
338 // return always the same hash code for this instance (immutable)
339 //
340 return myHashCode.intValue();
341 }
342
343 /**
344 * Returns a string representation of this <code>TabularType</code> instance.
345 * <p>
346 * The string representation consists of the name of this class (ie <code>javax.management.openmbean.TabularType</code>),
347 * the type name for this instance, the row type string representation of this instance,
348 * and the index names of this instance.
349 * <p>
350 * As <code>TabularType</code> instances are immutable, the string representation for this instance is calculated once,
351 * on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.
352 *
353 * @return a string representation of this <code>TabularType</code> instance
354 */
355 public String toString() {
356
357 // Calculate the string representation if it has not yet been done (ie 1st call to toString())
358 //
359 if (myToString == null) {
360 final StringBuilder result = new StringBuilder()
361 .append(this.getClass().getName())
362 .append("(name=")
363 .append(getTypeName())
364 .append(",rowType=")
365 .append(rowType.toString())
366 .append(",indexNames=(");
367 int i=0;
368 Iterator k = indexNames.iterator();
369 while( k.hasNext() ) {
370 if (i > 0) result.append(",");
371 result.append(k.next().toString());
372 i++;
373 }
374 result.append("))");
375 myToString = result.toString();
376 }
377
378 // return always the same string representation for this instance (immutable)
379 //
380 return myToString;
381 }
382
383 }
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