1 /*
2 * Copyright (c) 1999, 2017, 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 package javax.management;
27
28 import com.sun.jmx.mbeanserver.Introspector;
29 import java.lang.annotation.Annotation;
30 import java.lang.reflect.Method;
31 import java.util.Arrays;
32 import java.util.Objects;
33
34 /**
35 * Describes a management operation exposed by an MBean. Instances of
36 * this class are immutable. Subclasses may be mutable but this is
37 * not recommended.
38 *
39 * @since 1.5
40 */
41 public class MBeanOperationInfo extends MBeanFeatureInfo implements Cloneable {
42
43 /* Serial version */
44 static final long serialVersionUID = -6178860474881375330L;
45
46 static final MBeanOperationInfo[] NO_OPERATIONS =
47 new MBeanOperationInfo[0];
48
49 /**
50 * Indicates that the operation is read-like:
51 * it returns information but does not change any state.
52 */
53 public static final int INFO = 0;
54
55 /**
56 * Indicates that the operation is write-like: it has an effect but does
57 * not return any information from the MBean.
58 */
59 public static final int ACTION = 1;
60
61 /**
62 * Indicates that the operation is both read-like and write-like:
63 * it has an effect, and it also returns information from the MBean.
64 */
65 public static final int ACTION_INFO = 2;
66
67 /**
68 * Indicates that the impact of the operation is unknown or cannot be
69 * expressed using one of the other values.
70 */
71 public static final int UNKNOWN = 3;
72
73 /**
74 * @serial The method's return value.
75 */
76 private final String type;
77
78 /**
79 * @serial The signature of the method, that is, the class names
80 * of the arguments.
81 */
82 private final MBeanParameterInfo[] signature;
83
84 /**
85 * @serial The impact of the method, one of
86 * {@code INFO, ACTION, ACTION_INFO, UNKNOWN}.
87 */
88 private final int impact;
89
90 /** @see MBeanInfo#arrayGettersSafe */
91 private final transient boolean arrayGettersSafe;
92
93
94 /**
95 * Constructs an {@code MBeanOperationInfo} object. The
96 * {@link Descriptor} of the constructed object will include
97 * fields contributed by any annotations on the {@code Method}
98 * object that contain the {@link DescriptorKey} meta-annotation.
99 *
100 * @param method The {@code java.lang.reflect.Method} object
101 * describing the MBean operation.
102 * @param description A human readable description of the operation.
103 */
104 public MBeanOperationInfo(String description, Method method) {
105 this(method.getName(),
106 description,
107 methodSignature(method),
108 method.getReturnType().getName(),
109 UNKNOWN,
110 Introspector.descriptorForElement(method));
111 }
112
113 /**
114 * Constructs an {@code MBeanOperationInfo} object.
115 *
116 * @param name The name of the method.
117 * @param description A human readable description of the operation.
118 * @param signature {@code MBeanParameterInfo} objects
119 * describing the parameters(arguments) of the method. This may be
120 * null with the same effect as a zero-length array.
121 * @param type The type of the method's return value.
122 * @param impact The impact of the method, one of
123 * {@link #INFO}, {@link #ACTION}, {@link #ACTION_INFO},
124 * {@link #UNKNOWN}.
125 */
126 public MBeanOperationInfo(String name,
127 String description,
128 MBeanParameterInfo[] signature,
129 String type,
130 int impact) {
131 this(name, description, signature, type, impact, (Descriptor) null);
132 }
133
134 /**
135 * Constructs an {@code MBeanOperationInfo} object.
136 *
137 * @param name The name of the method.
138 * @param description A human readable description of the operation.
139 * @param signature {@code MBeanParameterInfo} objects
140 * describing the parameters(arguments) of the method. This may be
141 * null with the same effect as a zero-length array.
142 * @param type The type of the method's return value.
143 * @param impact The impact of the method, one of
144 * {@link #INFO}, {@link #ACTION}, {@link #ACTION_INFO},
145 * {@link #UNKNOWN}.
146 * @param descriptor The descriptor for the operation. This may be null
147 * which is equivalent to an empty descriptor.
148 *
149 * @throws IllegalArgumentException if {@code impact} is not one of {@code
150 * ACTION}, {@code ACTION_INFO}, {@code INFO}, or {@code UNKNOWN}.
151 *
152 * @since 1.6
153 */
154 public MBeanOperationInfo(String name,
155 String description,
156 MBeanParameterInfo[] signature,
157 String type,
158 int impact,
159 Descriptor descriptor) {
160
161 super(name, description, descriptor);
162
163 if (impact != ACTION && impact != ACTION_INFO && impact != INFO
164 && impact != UNKNOWN) {
165 throw new IllegalArgumentException("Argument impact can only be "
166 + "one of ACTION, ACTION_INFO, "
167 + "INFO, or UNKNOWN: " + impact);
168 }
169
170 if (signature == null || signature.length == 0)
171 signature = MBeanParameterInfo.NO_PARAMS;
172 else
173 signature = signature.clone();
174 this.signature = signature;
175 this.type = type;
176 this.impact = impact;
177 this.arrayGettersSafe =
178 MBeanInfo.arrayGettersSafe(this.getClass(),
179 MBeanOperationInfo.class);
180 }
181
182 /**
183 * <p>Returns a shallow clone of this instance.
184 * The clone is obtained by simply calling {@code super.clone()},
185 * thus calling the default native shallow cloning mechanism
186 * implemented by {@code Object.clone()}.
187 * No deeper cloning of any internal field is made.</p>
188 *
189 * <p>Since this class is immutable, cloning is chiefly of interest
190 * to subclasses.</p>
191 */
192 @Override
193 public Object clone () {
194 try {
195 return super.clone() ;
196 } catch (CloneNotSupportedException e) {
197 // should not happen as this class is cloneable
198 return null;
199 }
200 }
201
202 /**
203 * Returns the type of the method's return value.
204 *
205 * @return the return type.
206 */
207 public String getReturnType() {
208 return type;
209 }
210
211 /**
212 * <p>Returns the list of parameters for this operation. Each
213 * parameter is described by an {@code MBeanParameterInfo}
214 * object.</p>
215 *
216 * <p>The returned array is a shallow copy of the internal array,
217 * which means that it is a copy of the internal array of
218 * references to the {@code MBeanParameterInfo} objects but
219 * that each referenced {@code MBeanParameterInfo} object is
220 * not copied.</p>
221 *
222 * @return An array of {@code MBeanParameterInfo} objects.
223 */
224 public MBeanParameterInfo[] getSignature() {
225 // If MBeanOperationInfo was created in our implementation,
226 // signature cannot be null - because our constructors replace
227 // null with MBeanParameterInfo.NO_PARAMS;
228 //
229 // However, signature could be null if an MBeanOperationInfo is
230 // deserialized from a byte array produced by another implementation.
231 // This is not very likely but possible, since the serial form says
232 // nothing against it. (see 6373150)
233 //
234 if (signature == null)
235 // if signature is null simply return an empty array .
236 //
237 return MBeanParameterInfo.NO_PARAMS;
238 else if (signature.length == 0)
239 return signature;
240 else
241 return signature.clone();
242 }
243
244 private MBeanParameterInfo[] fastGetSignature() {
245 if (arrayGettersSafe) {
246 // if signature is null simply return an empty array .
247 // see getSignature() above.
248 //
249 if (signature == null)
250 return MBeanParameterInfo.NO_PARAMS;
251 else return signature;
252 } else return getSignature();
253 }
254
255 /**
256 * Returns the impact of the method, one of
257 * {@code INFO, ACTION, ACTION_INFO, UNKNOWN}.
258 *
259 * @return the impact code.
260 */
261 public int getImpact() {
262 return impact;
263 }
264
265 @Override
266 public String toString() {
267 String impactString = "";
268 switch (getImpact()) {
269 case ACTION: impactString = "action"; break;
270 case ACTION_INFO: impactString = "action/info"; break;
271 case INFO: impactString = "info"; break;
272 case UNKNOWN: impactString = "unknown"; break;
273 }
274 return getClass().getName() + "[" +
275 "description=" + getDescription() + ", " +
276 "name=" + getName() + ", " +
277 "returnType=" + getReturnType() + ", " +
278 "signature=" + Arrays.asList(fastGetSignature()) + ", " +
279 "impact=" + impactString + ", " +
280 "descriptor=" + getDescriptor() +
281 "]";
282 }
283
284 /**
285 * Compare this MBeanOperationInfo to another.
286 *
287 * @param o the object to compare to.
288 *
289 * @return true if and only if {@code o} is an MBeanOperationInfo such
290 * that its {@link #getName()}, {@link #getReturnType()}, {@link
291 * #getDescription()}, {@link #getImpact()}, {@link #getDescriptor()}
292 * and {@link #getSignature()} values are equal (not necessarily identical)
293 * to those of this MBeanConstructorInfo. Two signature arrays
294 * are equal if their elements are pairwise equal.
295 */
296 @Override
297 public boolean equals(Object o) {
298 if (o == this)
299 return true;
300 if (!(o instanceof MBeanOperationInfo))
301 return false;
302 MBeanOperationInfo p = (MBeanOperationInfo) o;
303 return (Objects.equals(p.getName(), getName()) &&
304 Objects.equals(p.getReturnType(), getReturnType()) &&
305 Objects.equals(p.getDescription(), getDescription()) &&
306 p.getImpact() == getImpact() &&
307 Arrays.equals(p.fastGetSignature(), fastGetSignature()) &&
308 Objects.equals(p.getDescriptor(), getDescriptor()));
309 }
310
311 /* We do not include everything in the hashcode. We assume that
312 if two operations are different they'll probably have different
313 names or types. The penalty we pay when this assumption is
314 wrong should be less than the penalty we would pay if it were
315 right and we needlessly hashed in the description and the
316 parameter array. */
317 @Override
318 public int hashCode() {
319 return Objects.hash(getName(), getReturnType());
320 }
321
322 private static MBeanParameterInfo[] methodSignature(Method method) {
323 final Class<?>[] classes = method.getParameterTypes();
324 final Annotation[][] annots = method.getParameterAnnotations();
325 return parameters(classes, annots);
326 }
327
328 static MBeanParameterInfo[] parameters(Class<?>[] classes,
329 Annotation[][] annots) {
330 final MBeanParameterInfo[] params =
331 new MBeanParameterInfo[classes.length];
332 assert(classes.length == annots.length);
333
334 for (int i = 0; i < classes.length; i++) {
335 Descriptor d = Introspector.descriptorForAnnotations(annots[i]);
336 final String pn = "p" + (i + 1);
337 params[i] =
338 new MBeanParameterInfo(pn, classes[i].getName(), "", d);
339 }
340
341 return params;
342 }
343 }