1 /* VMMemoryMXBeanImpl.java - VM impl. of a memory bean
2 Copyright (C) 2006, 2010 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
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)
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.
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
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
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. */
38 package gnu.java.lang.management;
40 import java.lang.management.ManagementFactory;
41 import java.lang.management.MemoryPoolMXBean;
42 import java.lang.management.MemoryType;
43 import java.lang.management.MemoryUsage;
45 import java.util.Iterator;
46 import java.util.List;
49 * Provides access to information about the memory
50 * management of the current invocation of the virtual
51 * machine. Instances of this bean are obtained by calling
52 * {@link ManagementFactory#getMemoryMXBean()}.
54 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
57 final class VMMemoryMXBeanImpl
60 private VMMemoryMXBeanImpl() {} // Prohibits instantiation.
63 * Returns an instance of {@link java.lang.management.MemoryUsage}
64 * with appropriate initial, used, committed and maximum values
65 * for the heap. By default, this uses the methods of
66 * {@link java.lang.Runtime} to provide some of the values.
68 * @return an {@link java.lang.management.MemoryUsage} instance
71 static MemoryUsage getHeapMemoryUsage()
73 return getUsage(MemoryType.HEAP);
77 * Returns an instance of {@link java.lang.management.MemoryUsage}
78 * with appropriate initial, used, committed and maximum values
79 * for non-heap memory.
81 * @return an {@link java.lang.management.MemoryUsage} instance
82 * for non-heap memory.
84 static MemoryUsage getNonHeapMemoryUsage()
86 return getUsage(MemoryType.NON_HEAP);
90 * Returns the number of objects ready to be garbage collected.
92 * @return the number of finalizable objects.
94 static native int getObjectPendingFinalizationCount();
97 * Returns true if the virtual machine will emit additional
98 * information when memory is allocated and deallocated. The
99 * format of the output is left up to the virtual machine.
101 * @return true if verbose memory usage output is on.
103 static native boolean isVerbose();
106 * Turns on or off the emission of additional information
107 * when memory is allocated and deallocated. The format of the
108 * output is left up to the virtual machine. This method
109 * may be called by multiple threads concurrently, but there
110 * is only one global setting of verbosity that is affected.
112 * @param verbose the new setting for verbose memory usage
115 static native void setVerbose(boolean verbose);
118 * Totals the memory usage from all the pools that match
121 * @param type the type of memory pools to accumulate
122 * (heap or non-heap).
123 * @return the memory usage overall.
125 private static MemoryUsage getUsage(MemoryType type) {
126 long init = 0, committed = 0, used = 0, max = 0;
128 ManagementFactory.getMemoryPoolMXBeans().iterator();
129 while (pools.hasNext())
131 MemoryPoolMXBean pool = (MemoryPoolMXBean) pools.next();
132 if (pool.getType() == type)
134 MemoryUsage usage = pool.getUsage();
137 long poolInit = usage.getInit();
143 committed += usage.getCommitted();
144 used += usage.getUsed();
147 long poolMax = usage.getMax();
155 return new MemoryUsage(init, used, committed, max);