PerfCounters.java revision 10420:c558850fac57 
1/*
2 * Copyright (c) 2013, 2015, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24import sun.jvmstat.monitor.Monitor;
25import sun.jvmstat.monitor.MonitorException;
26import sun.jvmstat.monitor.MonitoredHost;
27import sun.jvmstat.monitor.MonitoredVm;
28import sun.jvmstat.monitor.VmIdentifier;
29import jdk.test.lib.ProcessTools;
30
31/**
32 * PerfCounters can be used to get a performance counter from the currently
33 * executing VM.
34 *
35 * Throws a runtime exception if an error occurs while communicating with the
36 * currently executing VM.
37 */
38public class PerfCounters {
39    private final static MonitoredVm vm;
40
41    static {
42        try {
43            String pid = Integer.toString(ProcessTools.getProcessId());
44            VmIdentifier vmId = new VmIdentifier(pid);
45            MonitoredHost host = MonitoredHost.getMonitoredHost(vmId);
46            vm = host.getMonitoredVm(vmId);
47        } catch (Exception e) {
48            throw new RuntimeException("Could not connect to the VM");
49        }
50    }
51
52    /**
53     * Returns the performance counter with the given name.
54     *
55     * @param name The name of the performance counter.
56     * @throws IllegalArgumentException If no counter with the given name exists.
57     * @throws MonitorException If an error occurs while communicating with the VM.
58     * @return The performance counter with the given name.
59     */
60    public static PerfCounter findByName(String name)
61        throws MonitorException, IllegalArgumentException {
62        Monitor m = vm.findByName(name);
63        if (m == null) {
64            throw new IllegalArgumentException("Did not find a performance counter with name " + name);
65        }
66        return new PerfCounter(m, name);
67    }
68}
69