1 /*
2 * Copyright (c) 1999, 2013, 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</CODE>,
87 * <CODE>ACTION</CODE>,
88 * <CODE>ACTION_INFO</CODE>,
89 * <CODE>UNKNOWN</CODE>
90 */
91 private final int impact;
92
93 /** @see MBeanInfo#arrayGettersSafe */
94 private final transient boolean arrayGettersSafe;
95
96
97 /**
98 * Constructs an <CODE>MBeanOperationInfo</CODE> object. The
99 * {@link Descriptor} of the constructed object will include
100 * fields contributed by any annotations on the {@code Method}
101 * object that contain the {@link DescriptorKey} meta-annotation.
102 *
103 * @param method The <CODE>java.lang.reflect.Method</CODE> object
104 * describing the MBean operation.
105 * @param description A human readable description of the operation.
106 */
107 public MBeanOperationInfo(String description, Method method) {
108 this(method.getName(),
109 description,
110 methodSignature(method),
111 method.getReturnType().getName(),
112 UNKNOWN,
113 Introspector.descriptorForElement(method));
114 }
115
116 /**
117 * Constructs an <CODE>MBeanOperationInfo</CODE> object.
118 *
119 * @param name The name of the method.
120 * @param description A human readable description of the operation.
121 * @param signature <CODE>MBeanParameterInfo</CODE> objects
122 * describing the parameters(arguments) of the method. This may be
123 * null with the same effect as a zero-length array.
124 * @param type The type of the method's return value.
125 * @param impact The impact of the method, one of
126 * {@link #INFO}, {@link #ACTION}, {@link #ACTION_INFO},
127 * {@link #UNKNOWN}.
128 */
129 public MBeanOperationInfo(String name,
130 String description,
131 MBeanParameterInfo[] signature,
132 String type,
133 int impact) {
134 this(name, description, signature, type, impact, (Descriptor) null);
135 }
136
137 /**
138 * Constructs an <CODE>MBeanOperationInfo</CODE> object.
139 *
140 * @param name The name of the method.
141 * @param description A human readable description of the operation.
142 * @param signature <CODE>MBeanParameterInfo</CODE> objects
143 * describing the parameters(arguments) of the method. This may be
144 * null with the same effect as a zero-length array.
145 * @param type The type of the method's return value.
146 * @param impact The impact of the method, one of
147 * {@link #INFO}, {@link #ACTION}, {@link #ACTION_INFO},
148 * {@link #UNKNOWN}.
149 * @param descriptor The descriptor for the operation. This may be null
150 * which is equivalent to an empty descriptor.
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 (signature == null || signature.length == 0)
164 signature = MBeanParameterInfo.NO_PARAMS;
165 else
166 signature = signature.clone();
167 this.signature = signature;
168 this.type = type;
169 this.impact = impact;
170 this.arrayGettersSafe =
171 MBeanInfo.arrayGettersSafe(this.getClass(),
172 MBeanOperationInfo.class);
173 }
174
175 /**
176 * <p>Returns a shallow clone of this instance.
177 * The clone is obtained by simply calling <tt>super.clone()</tt>,
178 * thus calling the default native shallow cloning mechanism
179 * implemented by <tt>Object.clone()</tt>.
180 * No deeper cloning of any internal field is made.</p>
181 *
182 * <p>Since this class is immutable, cloning is chiefly of interest
183 * to subclasses.</p>
184 */
185 @Override
186 public Object clone () {
187 try {
188 return super.clone() ;
189 } catch (CloneNotSupportedException e) {
190 // should not happen as this class is cloneable
191 return null;
192 }
193 }
194
195 /**
196 * Returns the type of the method's return value.
197 *
198 * @return the return type.
199 */
200 public String getReturnType() {
201 return type;
202 }
203
204 /**
205 * <p>Returns the list of parameters for this operation. Each
206 * parameter is described by an <CODE>MBeanParameterInfo</CODE>
207 * object.</p>
208 *
209 * <p>The returned array is a shallow copy of the internal array,
210 * which means that it is a copy of the internal array of
211 * references to the <CODE>MBeanParameterInfo</CODE> objects but
212 * that each referenced <CODE>MBeanParameterInfo</CODE> object is
213 * not copied.</p>
214 *
215 * @return An array of <CODE>MBeanParameterInfo</CODE> objects.
216 */
217 public MBeanParameterInfo[] getSignature() {
218 // If MBeanOperationInfo was created in our implementation,
219 // signature cannot be null - because our constructors replace
220 // null with MBeanParameterInfo.NO_PARAMS;
221 //
222 // However, signature could be null if an MBeanOperationInfo is
223 // deserialized from a byte array produced by another implementation.
224 // This is not very likely but possible, since the serial form says
225 // nothing against it. (see 6373150)
226 //
227 if (signature == null)
228 // if signature is null simply return an empty array .
229 //
230 return MBeanParameterInfo.NO_PARAMS;
231 else if (signature.length == 0)
232 return signature;
233 else
234 return signature.clone();
235 }
236
237 private MBeanParameterInfo[] fastGetSignature() {
238 if (arrayGettersSafe) {
239 // if signature is null simply return an empty array .
240 // see getSignature() above.
241 //
242 if (signature == null)
243 return MBeanParameterInfo.NO_PARAMS;
244 else return signature;
245 } else return getSignature();
246 }
247
248 /**
249 * Returns the impact of the method, one of
250 * <CODE>INFO</CODE>, <CODE>ACTION</CODE>, <CODE>ACTION_INFO</CODE>, <CODE>UNKNOWN</CODE>.
251 *
252 * @return the impact code.
253 */
254 public int getImpact() {
255 return impact;
256 }
257
258 @Override
259 public String toString() {
260 String impactString;
261 switch (getImpact()) {
262 case ACTION: impactString = "action"; break;
263 case ACTION_INFO: impactString = "action/info"; break;
264 case INFO: impactString = "info"; break;
265 case UNKNOWN: impactString = "unknown"; break;
266 default: impactString = "(" + getImpact() + ")";
267 }
268 return getClass().getName() + "[" +
269 "description=" + getDescription() + ", " +
270 "name=" + getName() + ", " +
271 "returnType=" + getReturnType() + ", " +
272 "signature=" + Arrays.asList(fastGetSignature()) + ", " +
273 "impact=" + impactString + ", " +
274 "descriptor=" + getDescriptor() +
275 "]";
276 }
277
278 /**
279 * Compare this MBeanOperationInfo to another.
280 *
281 * @param o the object to compare to.
282 *
283 * @return true if and only if <code>o</code> is an MBeanOperationInfo such
284 * that its {@link #getName()}, {@link #getReturnType()}, {@link
285 * #getDescription()}, {@link #getImpact()}, {@link #getDescriptor()}
286 * and {@link #getSignature()} values are equal (not necessarily identical)
287 * to those of this MBeanConstructorInfo. Two signature arrays
288 * are equal if their elements are pairwise equal.
289 */
290 @Override
291 public boolean equals(Object o) {
292 if (o == this)
293 return true;
294 if (!(o instanceof MBeanOperationInfo))
295 return false;
296 MBeanOperationInfo p = (MBeanOperationInfo) o;
297 return (Objects.equals(p.getName(), getName()) &&
298 Objects.equals(p.getReturnType(), getReturnType()) &&
299 Objects.equals(p.getDescription(), getDescription()) &&
300 p.getImpact() == getImpact() &&
301 Arrays.equals(p.fastGetSignature(), fastGetSignature()) &&
302 Objects.equals(p.getDescriptor(), getDescriptor()));
303 }
304
305 /* We do not include everything in the hashcode. We assume that
306 if two operations are different they'll probably have different
307 names or types. The penalty we pay when this assumption is
308 wrong should be less than the penalty we would pay if it were
309 right and we needlessly hashed in the description and the
310 parameter array. */
311 @Override
312 public int hashCode() {
313 return Objects.hash(getName(), getReturnType());
314 }
315
316 private static MBeanParameterInfo[] methodSignature(Method method) {
317 final Class<?>[] classes = method.getParameterTypes();
318 final Annotation[][] annots = method.getParameterAnnotations();
319 return parameters(classes, annots);
320 }
321
322 static MBeanParameterInfo[] parameters(Class<?>[] classes,
323 Annotation[][] annots) {
324 final MBeanParameterInfo[] params =
325 new MBeanParameterInfo[classes.length];
326 assert(classes.length == annots.length);
327
328 for (int i = 0; i < classes.length; i++) {
329 Descriptor d = Introspector.descriptorForAnnotations(annots[i]);
330 final String pn = "p" + (i + 1);
331 params[i] =
332 new MBeanParameterInfo(pn, classes[i].getName(), "", d);
333 }
334
335 return params;
336 }
337 }