1 /* 2 * Copyright (c) 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. 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 24 package com.oracle.java.testlibrary; 25 26 import sun.jvmstat.monitor.Monitor; 27 28 /** 29 * Represents a performance counter in the JVM. 30 * 31 * See http://openjdk.java.net/groups/hotspot/docs/Serviceability.html#bjvmstat 32 * for more details about performance counters. 33 */ 34 public class PerfCounter { 35 private final Monitor monitor; 36 private final String name; 37 38 PerfCounter(Monitor monitor, String name) { 39 this.monitor = monitor; 40 this.name = name; 41 } 42 43 /** 44 * Returns the value of this performance counter as a long. 45 * 46 * @return The long value of this performance counter 47 * @throws RuntimeException If the value of the performance counter isn't a long 48 */ 49 public long longValue() { 50 Object value = monitor.getValue(); 51 if (value instanceof Long) { 52 return ((Long) value).longValue(); 53 } 54 throw new RuntimeException("Expected " + monitor.getName() + " to have a long value"); 55 } 56 57 /** 58 * Returns the name of the performance counter. 59 * 60 * @return The name of the performance counter. 61 */ 62 public String getName() { 63 return name; 64 } 65 66 @Override 67 public String toString() { 68 return name; 69 } 70 }