1 /*
2 * Copyright (c) 2004, 2014, 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 sun.jvmstat.perfdata.monitor;
27
28 import sun.jvmstat.monitor.*;
29 import java.util.*;
30 import java.io.*;
31 import java.lang.reflect.*;
32 import java.nio.ByteBuffer;
33
34 /**
35 * Abstraction for the HotSpot PerfData instrumentation buffer. This class
36 * is responsible for acquiring access to the instrumentation buffer for
37 * a target HotSpot Java Virtual Machine and providing method level access
38 * to its contents.
39 *
40 * @author Brian Doherty
41 * @since 1.5
42 */
43 public abstract class AbstractPerfDataBuffer {
44
45 /**
46 * Reference to the concrete instance created by the
47 * {@link #createPerfDataBuffer} method.
48 */
49 protected PerfDataBufferImpl impl;
50
51 /**
52 * Get the Local Java Virtual Machine Identifier, or <em>lvmid</em>
53 * for the target JVM associated with this instrumentation buffer.
54 *
55 * @return int - the lvmid
56 */
57 public int getLocalVmId() {
58 return impl.getLocalVmId();
59 }
60
61 /**
62 * Get a copy of the raw instrumentation data.
63 * This method is used to get a copy of the current bytes in the
64 * instrumentation buffer. It is generally used for transporting
65 * those bytes over the network.
66 *
67 * @return byte[] - a copy of the bytes in the instrumentation buffer.
68 */
69 public byte[] getBytes() {
70 return impl.getBytes();
71 }
72
73 /**
74 * Get the capacity of the instrumentation buffer.
75 *
76 * @return int - the capacity, or size, of the instrumentation buffer.
77 */
78 public int getCapacity() {
79 return impl.getCapacity();
80 }
81
82 /**
83 * Find a named Instrumentation object.
84 *
85 * This method will look for the named instrumentation object in the
86 * instrumentation exported by this Java Virtual Machine. If an
87 * instrumentation object with the given name exists, a Monitor interface
88 * to that object will be return. Otherwise, the method returns
89 * {@code null}.
90 *
91 * @param name the name of the Instrumentation object to find.
92 * @return Monitor - the {@link Monitor} object that can be used to
93 * monitor the named instrumentation object, or
94 * {@code null} if the named object doesn't exist.
95 * @throws MonitorException Thrown if an error occurs while communicating
96 * with the target Java Virtual Machine.
97 */
98 public Monitor findByName(String name) throws MonitorException {
99 return impl.findByName(name);
100 }
101
102 /**
103 * Find all Instrumentation objects with names matching the given pattern.
104 *
105 * This method returns a {@link List} of Monitor objects such that
106 * the name of each object matches the given pattern.
107 *
108 * @param patternString a string containing a pattern as described in
109 * {@link java.util.regex.Pattern}.
110 * @return {@code List<Monitor>} - a List of {@link Monitor}
111 * objects that can be used to
112 * monitor the instrumentation objects whose names match
113 * the given pattern. If no instrumentation objects have`
114 * names matching the given pattern, then an empty List
115 * is returned.
116 * @throws MonitorException Thrown if an error occurs while communicating
117 * with the target Java Virtual Machine.
118 * @see java.util.regex.Pattern
119 */
120 public List<Monitor> findByPattern(String patternString) throws MonitorException {
121 return impl.findByPattern(patternString);
122 }
123
124 /**
125 * Get a list of the inserted and removed monitors since last called.
126 *
127 * @return MonitorStatus - the status of available Monitors for the
128 * target Java Virtual Machine.
129 * @throws MonitorException Thrown if communications errors occur
130 * while communicating with the target.
131 */
132 public MonitorStatus getMonitorStatus() throws MonitorException {
133 return impl.getMonitorStatus();
134 }
135
136 /**
137 * Get the ByteBuffer containing the instrumentation data.
138 *
139 * @return ByteBuffer - a ByteBuffer object that refers to the
140 * instrumentation data.
141 */
142 public ByteBuffer getByteBuffer() {
143 return impl.getByteBuffer();
144 }
145
146 /**
147 * Create the perfdata instrumentation buffer for the given lvmid
148 * using the given ByteBuffer object as the source of the instrumentation
149 * data. This method parses the instrumentation buffer header to determine
150 * key characteristics of the instrumentation buffer and then dynamically
151 * loads the appropriate class to handle the particular instrumentation
152 * version.
153 *
154 * @param bb the ByteBuffer that references the instrumentation data.
155 * @param lvmid the Local Java Virtual Machine identifier for this
156 * instrumentation buffer.
157 *
158 * @throws MonitorException
159 */
160 protected void createPerfDataBuffer(ByteBuffer bb, int lvmid)
161 throws MonitorException {
162 int majorVersion = AbstractPerfDataBufferPrologue.getMajorVersion(bb);
163 int minorVersion = AbstractPerfDataBufferPrologue.getMinorVersion(bb);
164
165 // instantiate the version specific class
166 String classname = "sun.jvmstat.perfdata.monitor.v"
167 + majorVersion + "_" + minorVersion
168 + ".PerfDataBuffer";
169
170 try {
171 Class<?> implClass = Class.forName(classname);
172 Constructor<?> cons = implClass.getConstructor(new Class<?>[] {
173 Class.forName("java.nio.ByteBuffer"),
174 Integer.TYPE
175 });
176
177 impl = (PerfDataBufferImpl)cons.newInstance(new Object[] {
178 bb, lvmid
179 });
180
181 } catch (ClassNotFoundException e) {
182 // from Class.forName();
183 throw new IllegalArgumentException(
184 "Could not find " + classname + ": " + e.getMessage(), e);
185
186 } catch (NoSuchMethodException e) {
187 // from Class.getConstructor();
188 throw new IllegalArgumentException(
189 "Expected constructor missing in " + classname + ": "
190 + e.getMessage(), e);
191
192 } catch (IllegalAccessException e) {
193 // from Constructor.newInstance()
194 throw new IllegalArgumentException(
195 "Unexpected constructor access in " + classname + ": "
196 + e.getMessage(), e);
197
198 } catch (InstantiationException e) {
199 throw new IllegalArgumentException(
200 classname + "is abstract: " + e.getMessage(), e);
201
202 } catch (InvocationTargetException e) {
203 Throwable cause = e.getCause();
204 if (cause instanceof MonitorException) {
205 throw (MonitorException)cause;
206 }
207 throw new RuntimeException("Unexpected exception: "
208 + e.getMessage() , e);
209 }
210 }
211 }