1 /* VMMemoryMXBeanImpl.java - VM impl. of a memory bean 2 Copyright (C) 2006 Free Software Foundation 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 package gnu.java.lang.management; 39 40 import java.lang.management.MemoryUsage; 41 42 /** 43 * Provides access to information about the memory 44 * management of the current invocation of the virtual 45 * machine. Instances of this bean are obtained by calling 46 * {@link ManagementFactory#getMemoryMXBean()}. 47 * 48 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 49 * @since 1.5 50 */ 51 final class VMMemoryMXBeanImpl 52 { 53 54 /** 55 * Returns an instance of {@link java.lang.management.MemoryUsage} 56 * with appropriate initial, used, committed and maximum values 57 * for the heap. By default, this uses the methods of 58 * {@link java.lang.Runtime} to provide some of the values. 59 * 60 * @return an {@link java.lang.management.MemoryUsage} instance 61 * for the heap. 62 */ getHeapMemoryUsage()63 static MemoryUsage getHeapMemoryUsage() 64 { 65 Runtime runtime = Runtime.getRuntime(); 66 long totalMem = runtime.totalMemory(); 67 return new MemoryUsage(-1, totalMem - runtime.freeMemory(), 68 totalMem, runtime.maxMemory()); 69 } 70 71 /** 72 * Returns an instance of {@link java.lang.management.MemoryUsage} 73 * with appropriate initial, used, committed and maximum values 74 * for non-heap memory. 75 * 76 * @return an {@link java.lang.management.MemoryUsage} instance 77 * for non-heap memory. 78 */ getNonHeapMemoryUsage()79 static native MemoryUsage getNonHeapMemoryUsage(); 80 81 /** 82 * Returns the number of objects ready to be garbage collected. 83 * 84 * @return the number of finalizable objects. 85 */ getObjectPendingFinalizationCount()86 static native int getObjectPendingFinalizationCount(); 87 88 /** 89 * Returns true if the virtual machine will emit additional 90 * information when memory is allocated and deallocated. The 91 * format of the output is left up to the virtual machine. 92 * 93 * @return true if verbose class loading output is on. 94 */ isVerbose()95 static native boolean isVerbose(); 96 97 /** 98 * Turns on or off the emission of additional information 99 * when memory is allocated and deallocated. The format of the 100 * output is left up to the virtual machine. This method 101 * may be called by multiple threads concurrently, but there 102 * is only one global setting of verbosity that is affected. 103 * 104 * @param verbose the new setting for verbose class loading 105 * output. 106 */ setVerbose(boolean verbose)107 static native void setVerbose(boolean verbose); 108 109 } 110