1 /* VMGarbageCollectorMXBeanImpl.java - VM interface for a GC bean 2 Copyright (C) 2006, 2010 Free Software Foundation, Inc. 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 /** 41 * Provides access to information about the garbage collectors 42 * of the virtual machine. Garbage collectors are responsible 43 * for removing unreferenced objects from memory. A garbage 44 * collector is a type of memory manager, so this interface 45 * is combined with that of generic memory managers. An instance 46 * of this bean for each garbage collector is obtained by calling 47 * {@link ManagementFactory#getGarbageCollectorMXBeans()}. 48 * 49 * @author Andrew John Hughes (gnu_andrew@member.fsf.org) 50 * @since 1.5 51 */ 52 final class VMGarbageCollectorMXBeanImpl 53 { 54 VMGarbageCollectorMXBeanImpl()55 private VMGarbageCollectorMXBeanImpl() {} // Prohibits instantiation. 56 57 /** 58 * Returns the number of collections the garbage collector 59 * represented by this bean has made. -1 is returned if the 60 * collection count is undefined. 61 * 62 * @param name the name of the garbage collector. 63 * @return the number of collections made, or -1 if this is 64 * undefined. 65 */ getCollectionCount(String name)66 static native long getCollectionCount(String name); 67 68 /** 69 * Returns the accumulated number of milliseconds this garbage 70 * collector has spent freeing the memory used by unreferenced 71 * objects. -1 is returned if the collection time is undefined. 72 * Note that the accumulated time may not change, even when the 73 * collection count increases, if the time taken is sufficiently 74 * short; this depends on the resolution of the timer used. 75 * 76 * @param name the name of the garbage collector. 77 * @return the accumulated number of milliseconds spent collecting, 78 * or -1 if this is undefined. 79 */ getCollectionTime(String name)80 static native long getCollectionTime(String name); 81 82 } 83