1 /*
2 * Copyright (c) 2000, 2008, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26
27 package javax.management.openmbean;
28
29
30 // java import
31 //
32 import java.io.InvalidObjectException;
33 import java.io.ObjectStreamException;
34 import java.math.BigDecimal;
35 import java.math.BigInteger;
36 import java.util.Date;
37 import java.util.Map;
38 import java.util.HashMap;
39
40 // jmx import
41 //
42 import javax.management.ObjectName;
43
44
45 /**
46 * The <code>SimpleType</code> class is the <i>open type</i> class whose instances describe
47 * all <i>open data</i> values which are neither arrays,
48 * nor {@link CompositeData <code>CompositeData</code>} values,
49 * nor {@link TabularData <code>TabularData</code>} values.
50 * It predefines all its possible instances as static fields, and has no public constructor.
51 * <p>
52 * Given a <code>SimpleType</code> instance describing values whose Java class name is <i>className</i>,
53 * the internal fields corresponding to the name and description of this <code>SimpleType</code> instance
54 * are also set to <i>className</i>.
55 * In other words, its methods <code>getClassName</code>, <code>getTypeName</code> and <code>getDescription</code>
56 * all return the same string value <i>className</i>.
57 *
58 * @since 1.5
59 */
60 public final class SimpleType<T> extends OpenType<T> {
61
62 /* Serial version */
63 static final long serialVersionUID = 2215577471957694503L;
64
65 // SimpleType instances.
66 // IF YOU ADD A SimpleType, YOU MUST UPDATE OpenType and typeArray
67
68 /**
69 * The <code>SimpleType</code> instance describing values whose
70 * Java class name is <code>java.lang.Void</code>.
71 */
72 public static final SimpleType<Void> VOID =
73 new SimpleType<Void>(Void.class);
74
75 /**
76 * The <code>SimpleType</code> instance describing values whose
77 * Java class name is <code>java.lang.Boolean</code>.
78 */
79 public static final SimpleType<Boolean> BOOLEAN =
80 new SimpleType<Boolean>(Boolean.class);
81
82 /**
83 * The <code>SimpleType</code> instance describing values whose
84 * Java class name is <code>java.lang.Character</code>.
85 */
86 public static final SimpleType<Character> CHARACTER =
87 new SimpleType<Character>(Character.class);
88
89 /**
90 * The <code>SimpleType</code> instance describing values whose
91 * Java class name is <code>java.lang.Byte</code>.
92 */
93 public static final SimpleType<Byte> BYTE =
94 new SimpleType<Byte>(Byte.class);
95
96 /**
97 * The <code>SimpleType</code> instance describing values whose
98 * Java class name is <code>java.lang.Short</code>.
99 */
100 public static final SimpleType<Short> SHORT =
101 new SimpleType<Short>(Short.class);
102
103 /**
104 * The <code>SimpleType</code> instance describing values whose
105 * Java class name is <code>java.lang.Integer</code>.
106 */
107 public static final SimpleType<Integer> INTEGER =
108 new SimpleType<Integer>(Integer.class);
109
110 /**
111 * The <code>SimpleType</code> instance describing values whose
112 * Java class name is <code>java.lang.Long</code>.
113 */
114 public static final SimpleType<Long> LONG =
115 new SimpleType<Long>(Long.class);
116
117 /**
118 * The <code>SimpleType</code> instance describing values whose
119 * Java class name is <code>java.lang.Float</code>.
120 */
121 public static final SimpleType<Float> FLOAT =
122 new SimpleType<Float>(Float.class);
123
124 /**
125 * The <code>SimpleType</code> instance describing values whose
126 * Java class name is <code>java.lang.Double</code>.
127 */
128 public static final SimpleType<Double> DOUBLE =
129 new SimpleType<Double>(Double.class);
130
131 /**
132 * The <code>SimpleType</code> instance describing values whose
133 * Java class name is <code>java.lang.String</code>.
134 */
135 public static final SimpleType<String> STRING =
136 new SimpleType<String>(String.class);
137
138 /**
139 * The <code>SimpleType</code> instance describing values whose
140 * Java class name is <code>java.math.BigDecimal</code>.
141 */
142 public static final SimpleType<BigDecimal> BIGDECIMAL =
143 new SimpleType<BigDecimal>(BigDecimal.class);
144
145 /**
146 * The <code>SimpleType</code> instance describing values whose
147 * Java class name is <code>java.math.BigInteger</code>.
148 */
149 public static final SimpleType<BigInteger> BIGINTEGER =
150 new SimpleType<BigInteger>(BigInteger.class);
151
152 /**
153 * The <code>SimpleType</code> instance describing values whose
154 * Java class name is <code>java.util.Date</code>.
155 */
156 public static final SimpleType<Date> DATE =
157 new SimpleType<Date>(Date.class);
158
159 /**
160 * The <code>SimpleType</code> instance describing values whose
161 * Java class name is <code>javax.management.ObjectName</code>.
162 */
163 public static final SimpleType<ObjectName> OBJECTNAME =
164 new SimpleType<ObjectName>(ObjectName.class);
165
166 private static final SimpleType<?>[] typeArray = {
167 VOID, BOOLEAN, CHARACTER, BYTE, SHORT, INTEGER, LONG, FLOAT,
168 DOUBLE, STRING, BIGDECIMAL, BIGINTEGER, DATE, OBJECTNAME,
169 };
170
171
172 private transient Integer myHashCode = null; // As this instance is immutable, these two values
173 private transient String myToString = null; // need only be calculated once.
174
175
176 /* *** Constructor *** */
177
178 private SimpleType(Class<T> valueClass) {
179 super(valueClass.getName(), valueClass.getName(), valueClass.getName(),
180 false);
181 }
182
183
184 /* *** SimpleType specific information methods *** */
185
186 /**
187 * Tests whether <var>obj</var> is a value for this
188 * <code>SimpleType</code> instance. <p> This method returns
189 * <code>true</code> if and only if <var>obj</var> is not null and
190 * <var>obj</var>'s class name is the same as the className field
191 * defined for this <code>SimpleType</code> instance (ie the class
192 * name returned by the {@link OpenType#getClassName()
193 * getClassName} method).
194 *
195 * @param obj the object to be tested.
196 *
197 * @return <code>true</code> if <var>obj</var> is a value for this
198 * <code>SimpleType</code> instance.
199 */
200 public boolean isValue(Object obj) {
201
202 // if obj is null, return false
203 //
204 if (obj == null) {
205 return false;
206 }
207
208 // Test if obj's class name is the same as for this instance
209 //
210 return this.getClassName().equals(obj.getClass().getName());
211 }
212
213
214 /* *** Methods overriden from class Object *** */
215
216 /**
217 * Compares the specified <code>obj</code> parameter with this <code>SimpleType</code> instance for equality.
218 * <p>
219 * Two <code>SimpleType</code> instances are equal if and only if their
220 * {@link OpenType#getClassName() getClassName} methods return the same value.
221 *
222 * @param obj the object to be compared for equality with this <code>SimpleType</code> instance;
223 * if <var>obj</var> is <code>null</code> or is not an instance of the class <code>SimpleType</code>,
224 * <code>equals</code> returns <code>false</code>.
225 *
226 * @return <code>true</code> if the specified object is equal to this <code>SimpleType</code> instance.
227 */
228 public boolean equals(Object obj) {
229
230 /* If it weren't for readReplace(), we could replace this method
231 with just:
232 return (this == obj);
233 */
234
235 if (!(obj instanceof SimpleType<?>))
236 return false;
237
238 SimpleType<?> other = (SimpleType<?>) obj;
239
240 // Test if other's className field is the same as for this instance
241 //
242 return this.getClassName().equals(other.getClassName());
243 }
244
245 /**
246 * Returns the hash code value for this <code>SimpleType</code> instance.
247 * The hash code of a <code>SimpleType</code> instance is the the hash code of
248 * the string value returned by the {@link OpenType#getClassName() getClassName} method.
249 * <p>
250 * As <code>SimpleType</code> instances are immutable, the hash code for this instance is calculated once,
251 * on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.
252 *
253 * @return the hash code value for this <code>SimpleType</code> instance
254 */
255 public int hashCode() {
256
257 // Calculate the hash code value if it has not yet been done (ie 1st call to hashCode())
258 //
259 if (myHashCode == null) {
260 myHashCode = Integer.valueOf(this.getClassName().hashCode());
261 }
262
263 // return always the same hash code for this instance (immutable)
264 //
265 return myHashCode.intValue();
266 }
267
268 /**
269 * Returns a string representation of this <code>SimpleType</code> instance.
270 * <p>
271 * The string representation consists of
272 * the name of this class (ie <code>javax.management.openmbean.SimpleType</code>) and the type name
273 * for this instance (which is the java class name of the values this <code>SimpleType</code> instance represents).
274 * <p>
275 * As <code>SimpleType</code> instances are immutable, the string representation for this instance is calculated once,
276 * on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.
277 *
278 * @return a string representation of this <code>SimpleType</code> instance
279 */
280 public String toString() {
281
282 // Calculate the string representation if it has not yet been done (ie 1st call to toString())
283 //
284 if (myToString == null) {
285 myToString = this.getClass().getName()+ "(name="+ getTypeName() +")";
286 }
287
288 // return always the same string representation for this instance (immutable)
289 //
290 return myToString;
291 }
292
293 private static final Map<SimpleType<?>,SimpleType<?>> canonicalTypes =
294 new HashMap<SimpleType<?>,SimpleType<?>>();
295 static {
296 for (int i = 0; i < typeArray.length; i++) {
297 final SimpleType<?> type = typeArray[i];
298 canonicalTypes.put(type, type);
299 }
300 }
301
302 /**
303 * Replace an object read from an {@link
304 * java.io.ObjectInputStream} with the unique instance for that
305 * value.
306 *
307 * @return the replacement object.
308 *
309 * @exception ObjectStreamException if the read object cannot be
310 * resolved.
311 */
312 public Object readResolve() throws ObjectStreamException {
313 final SimpleType<?> canonical = canonicalTypes.get(this);
314 if (canonical == null) {
315 // Should not happen
316 throw new InvalidObjectException("Invalid SimpleType: " + this);
317 }
318 return canonical;
319 }
320 }