View Javadoc
1   /*
2    * Copyright (c) 2004, 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 sun.jvmstat.perfdata.monitor;
27  
28  import sun.jvmstat.monitor.*;
29  import java.util.*;
30  import java.nio.*;
31  import java.io.*;
32  import java.net.*;
33  import java.util.regex.*;
34  
35  /**
36   * The base classes for the concrete implementations of the HotSpot
37   * PerfData instrumentation buffer.
38   *
39   * @author Brian Doherty
40   * @since 1.5
41   * @see AbstractPerfDataBuffer
42   */
43  public abstract class PerfDataBufferImpl {
44  
45      /**
46       * The buffer containing the instrumentation data.
47       */
48      protected ByteBuffer buffer;
49  
50      /**
51       * A Map of monitor objects found in the instrumentation buffer.
52       */
53      protected Map<String, Monitor> monitors;
54  
55      /**
56       * The Local Java Virtual Machine Identifier for this buffer.
57       */
58      protected int lvmid;
59  
60      /**
61       * A Map of monitor object names to aliases as read in from the alias map
62       * file.
63       */
64      protected Map<String, ArrayList<String>> aliasMap;
65  
66      /**
67       * A cache of resolved monitor aliases.
68       */
69      protected Map aliasCache;
70  
71  
72      /**
73       * Constructor.
74       *
75       * @param buffer the ByteBuffer containing the instrumentation data.
76       * @param lvmid the Local Java Virtual Machine Identifier for this
77       *              instrumentation buffer.
78       */
79      protected PerfDataBufferImpl(ByteBuffer buffer, int lvmid) {
80          this.buffer = buffer;
81          this.lvmid = lvmid;
82          this.monitors = new TreeMap<String, Monitor>();
83          this.aliasMap = new HashMap<String, ArrayList<String>>();
84          this.aliasCache = new HashMap();
85      }
86  
87      /**
88       * Get the Local Java Virtual Machine Identifier, or <em>lvmid</em>
89       * for the target JVM associated with this instrumentation buffer.
90       *
91       * @return int - the lvmid
92       */
93      public int getLocalVmId() {
94          return lvmid;
95      }
96  
97      /**
98       * Get a copy of the raw instrumentation data.
99       * This method is used to get a copy of the current bytes in the
100      * instrumentation buffer. It is generally used for transporting
101      * those bytes over the network.
102      *
103      * @return byte[] - a copy of the bytes in the instrumentation buffer.
104      */
105     public byte[] getBytes() {
106         ByteBuffer bb = null;
107         synchronized (this) {
108             /*
109              * this operation is potentially time consuming, and the result
110              * is unused when the getBytes() interface is used. However, the
111              * call is necessary in order to synchronize this monitoring
112              * client with the target jvm, which assures that the receiver
113              * of the byte[] gets an image that is initialized to a usable
114              * state. Otherwise, they might only  get a snapshot of an
115              * empty instrumentation buffer immediately after it was created.
116              */
117             try {
118                 if (monitors.isEmpty()) {
119                     buildMonitorMap(monitors);
120                 }
121             } catch (MonitorException e) {
122                 /*
123                  * just ignore this here and let the receiver of the
124                  * byte[] detect and handle the problem.
125                  */
126             }
127             bb = buffer.duplicate();
128         }
129         bb.rewind();
130         byte[] bytes = new byte[bb.limit()];
131         bb.get(bytes);
132         return bytes;
133     }
134 
135     /**
136      * Get the capacity of the instrumentation buffer.
137      *
138      * @return int - the capacity, or size, of the instrumentation buffer.
139      */
140     public int getCapacity() {
141         return buffer.capacity();
142     }
143 
144     /**
145      * Get the ByteBuffer containing the instrumentation data.
146      *
147      * @return ByteBuffer - a ByteBuffer object that refers to the
148      *                      instrumentation data.
149      */
150     ByteBuffer getByteBuffer() {
151         // receiver is responsible for assuring that the buffer's state
152         // is that of an initialized target.
153         return buffer;
154     }
155 
156     /**
157      * Build the alias mapping. Uses the default alias map file unless
158      * the sun.jvmstat.perfdata.aliasmap file indicates some other
159      * file as the source.
160      */
161     private void buildAliasMap() {
162         assert Thread.holdsLock(this);
163 
164         URL aliasURL = null;
165         String filename = System.getProperty("sun.jvmstat.perfdata.aliasmap");
166 
167         if (filename != null) {
168             File f = new File(filename);
169             try {
170                 aliasURL = f.toURL();
171 
172             } catch (MalformedURLException e) {
173                 throw new IllegalArgumentException(e);
174             }
175         } else {
176             aliasURL = getClass().getResource(
177                 "/sun/jvmstat/perfdata/resources/aliasmap");
178         }
179 
180         assert aliasURL != null;
181 
182         AliasFileParser aliasParser = new AliasFileParser(aliasURL);
183 
184         try {
185             aliasParser.parse(aliasMap);
186 
187         } catch (IOException e) {
188             System.err.println("Error processing " + filename + ": "
189                                + e.getMessage());
190         } catch (SyntaxException e) {
191             System.err.println("Syntax error parsing " + filename + ": "
192                                + e.getMessage());
193         }
194     }
195 
196     /**
197      * Find the Monitor object for the named counter by using one of its
198      * aliases.
199      */
200     protected Monitor findByAlias(String name) {
201         assert Thread.holdsLock(this);
202 
203         Monitor  m = (Monitor)aliasCache.get(name);
204         if (m == null) {
205             ArrayList al = aliasMap.get(name);
206             if (al != null) {
207                 for (Iterator i = al.iterator(); i.hasNext() && m == null; ) {
208                     String alias = (String)i.next();
209                     m = (Monitor)monitors.get(alias);
210                 }
211             }
212         }
213         return m;
214     }
215 
216 
217     /**
218      * Find a named Instrumentation object.
219      *
220      * This method will look for the named instrumentation object in the
221      * instrumentation exported by this Java Virtual Machine. If an
222      * instrumentation object with the given name exists, a Monitor interface
223      * to that object will be return. Otherwise, the method returns
224      * <tt>null</tt>. The method will map requests for instrumention objects
225      * using old names to their current names, if applicable.
226      *
227      *
228      *
229      * @param name the name of the Instrumentation object to find.
230      * @return Monitor - the {@link Monitor} object that can be used to
231      *                   monitor the the named instrumentation object, or
232      *                   <tt>null</tt> if the named object doesn't exist.
233      * @throws MonitorException Thrown if an error occurs while communicating
234      *                          with the target Java Virtual Machine.
235      */
236     public Monitor findByName(String name) throws MonitorException {
237         Monitor m = null;
238 
239         synchronized (this) {
240             if (monitors.isEmpty()) {
241                 buildMonitorMap(monitors);
242                 buildAliasMap();
243             }
244 
245             // look for the requested monitor
246             m = monitors.get(name);
247             if (m == null) {
248                 // not found - load any new monitors, and try again.
249                 getNewMonitors(monitors);
250                 m = monitors.get(name);
251             }
252             if (m == null) {
253                 // still not found, look for aliases
254                 m = findByAlias(name);
255             }
256         }
257         return m;
258     }
259 
260     /**
261      * Find all Instrumentation objects with names matching the given pattern.
262      *
263      * This method returns a {@link List} of Monitor objects such that
264      * the name of each object matches the given pattern.
265      *
266      * @param patternString a string containing a pattern as described in
267      *                      {@link java.util.regex.Pattern}.
268      * @return List<Monitor> - a List of {@link Monitor} objects that can be used to
269      *                monitor the instrumentation objects whose names match
270      *                the given pattern. If no instrumentation objects have`
271      *                names matching the given pattern, then an empty List
272      *                is returned.
273      * @throws MonitorException Thrown if an error occurs while communicating
274      *                          with the target Java Virtual Machine.
275      * @see java.util.regex.Pattern
276      */
277     public List<Monitor> findByPattern(String patternString)
278                 throws MonitorException, PatternSyntaxException {
279 
280         synchronized(this) {
281             if (monitors.isEmpty()) {
282                 buildMonitorMap(monitors);
283             } else {
284                 getNewMonitors(monitors);
285             }
286         }
287 
288         Pattern pattern = Pattern.compile(patternString);
289         Matcher matcher = pattern.matcher("");
290         List<Monitor> matches = new ArrayList<Monitor>();
291 
292         Set monitorSet = monitors.entrySet();
293 
294         for (Iterator i = monitorSet.iterator(); i.hasNext(); /* empty */) {
295             Map.Entry me = (Map.Entry)i.next();
296             String name = (String)me.getKey();
297             Monitor m = (Monitor)me.getValue();
298 
299             // apply pattern to monitor item name
300             matcher.reset(name);
301 
302             // if the pattern matches, then add monitor to list
303             if (matcher.lookingAt()) {
304                  matches.add((Monitor)me.getValue());
305             }
306         }
307         return matches;
308     }
309 
310     /**
311      * Get a list of the inserted and removed monitors since last called.
312      *
313      * @return MonitorStatus - the status of available Monitors for the
314      *                         target Java Virtual Machine.
315      * @throws MonitorException Thrown if communications errors occur
316      *                          while communicating with the target.
317      */
318     public MonitorStatus getMonitorStatus() throws MonitorException {
319         synchronized(this) {
320             if (monitors.isEmpty()) {
321                 buildMonitorMap(monitors);
322             }
323             return getMonitorStatus(monitors);
324         }
325     }
326 
327     // PerfDataBuffer implementation specific classes
328 
329     /**
330      * get the list of inserted and removed monitors since last called.
331      *
332      * @param m the map of Monitors.
333      * @throws MonitorException Thrown if communications errors occur
334      *                          while communicating with the target.
335      */
336     protected abstract MonitorStatus getMonitorStatus(Map<String, Monitor> m)
337                                      throws MonitorException;
338 
339     /**
340      * build the map of Monitor objects.
341      *
342      * @param m the map of Monitors.
343      * @throws MonitorException Thrown if communications errors occur
344      *                          while communicating with the target.
345      */
346     protected abstract void buildMonitorMap(Map<String, Monitor> m) throws MonitorException;
347 
348     /**
349      * get the new Monitor objects from the Map of Monitor objects.
350      *
351      * @param m the map of Monitors.
352      * @throws MonitorException Thrown if communications errors occur
353      *                          while communicating with the target.
354      */
355     protected abstract void getNewMonitors(Map<String, Monitor> m) throws MonitorException;
356 }