/*
* Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Oracle nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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*/
/*
* This source code is provided to illustrate the usage of a given feature
* or technique and has been deliberately simplified. Additional steps
* required for a production-quality application, such as security checks,
* input validation and proper error handling, might not be present in
* this sample code.
*/
/*
*/
import static java.lang.management.ManagementFactory.*;
import java.lang.management.*;
import javax.management.*;
import java.io.*;
import java.util.*;
/**
* Example of using the java.lang.management API to monitor
* the memory usage and garbage collection statistics.
*
* @author Mandy Chung
*/
public class PrintGCStat {
private RuntimeMXBean rmbean;
private MemoryMXBean mmbean;
private List<MemoryPoolMXBean> pools;
private List<GarbageCollectorMXBean> gcmbeans;
/**
* Constructs a PrintGCStat object to monitor a remote JVM.
*/
public PrintGCStat(MBeanServerConnection server) throws IOException {
// Create the platform mxbean proxies
this.rmbean = newPlatformMXBeanProxy(server,
RUNTIME_MXBEAN_NAME,
RuntimeMXBean.class);
this.mmbean = newPlatformMXBeanProxy(server,
MEMORY_MXBEAN_NAME,
MemoryMXBean.class);
ObjectName poolName = null;
ObjectName gcName = null;
try {
poolName = new ObjectName(MEMORY_POOL_MXBEAN_DOMAIN_TYPE+",*");
gcName = new ObjectName(GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE+",*");
} catch (MalformedObjectNameException e) {
// should not reach here
assert(false);
}
Set<ObjectName> mbeans = server.queryNames(poolName, null);
if (mbeans != null) {
pools = new ArrayList<MemoryPoolMXBean>();
for (ObjectName objName : mbeans) {
MemoryPoolMXBean p =
newPlatformMXBeanProxy(server,
objName.getCanonicalName(),
MemoryPoolMXBean.class);
pools.add(p);
}
}
mbeans = server.queryNames(gcName, null);
if (mbeans != null) {
gcmbeans = new ArrayList<GarbageCollectorMXBean>();
for (ObjectName objName : mbeans) {
GarbageCollectorMXBean gc =
newPlatformMXBeanProxy(server,
objName.getCanonicalName(),
GarbageCollectorMXBean.class);
gcmbeans.add(gc);
}
}
}
/**
* Constructs a PrintGCStat object to monitor the local JVM.
*/
public PrintGCStat() {
// Obtain the platform mxbean instances for the running JVM.
this.rmbean = getRuntimeMXBean();
this.mmbean = getMemoryMXBean();
this.pools = getMemoryPoolMXBeans();
this.gcmbeans = getGarbageCollectorMXBeans();
}
/**
* Prints the verbose GC log to System.out to list the memory usage
* of all memory pools as well as the GC statistics.
*/
public void printVerboseGc() {
System.out.println("Uptime: " + formatMillis(rmbean.getUptime()));
System.out.println("Heap usage: " + mmbean.getHeapMemoryUsage());
System.out.println("Non-Heap memory usage: " + mmbean.getNonHeapMemoryUsage());
for (GarbageCollectorMXBean gc : gcmbeans) {
System.out.print(" [" + gc.getName() + ": ");
System.out.print("Count=" + gc.getCollectionCount());
System.out.print(" GCTime=" + formatMillis(gc.getCollectionTime()));
System.out.print("]");
}
System.out.println();
for (MemoryPoolMXBean p : pools) {
System.out.print(" [" + p.getName() + ":");
MemoryUsage u = p.getUsage();
System.out.print(" Used=" + formatBytes(u.getUsed()));
System.out.print(" Committed=" + formatBytes(u.getCommitted()));
System.out.println("]");
}
}
private String formatMillis(long ms) {
return String.format("%.4fsec", ms / (double) 1000);
}
private String formatBytes(long bytes) {
long kb = bytes;
if (bytes > 0) {
kb = bytes / 1024;
}
return kb + "K";
}
}