HeapUsageMonitor() {
int c = 0;
for (MemoryPoolMXBean m : ManagementFactory.getMemoryPoolMXBeans()) {
if (m.getType() != MemoryType.HEAP) // only interested in HEAP
continue;
if (m.isCollectionUsageThresholdSupported() && m.isUsageThresholdSupported()) {
// should be Old pool, get called when memory is critical
_oldGenBean = m;
_gc_callback = MEM_MAX;
// Really idiotic API: no idea what the usageThreshold is, so I have
// to guess. Start high, catch IAE & lower by 1/8th and try again.
while (true) {
try {
m.setCollectionUsageThreshold(_gc_callback);
break;
} catch (IllegalArgumentException iae) {
// Do NOT log this exception, it is expected and unavoidable and
// entirely handled.
_gc_callback -= (_gc_callback >> 3);
}
}
NotificationEmitter emitter = (NotificationEmitter) _allMemBean;
emitter.addNotificationListener(this, null, m);
++c;
}
}
assert c == 1;
}
public static void main(String[] argv) throws Exception {
memory = new ObjectName(MEMORY_MXBEAN_NAME);
runtime = new ObjectName(RUNTIME_MXBEAN_NAME);
thread = new ObjectName(THREAD_MXBEAN_NAME);
os = new ObjectName(OPERATING_SYSTEM_MXBEAN_NAME);
List<MemoryPoolMXBean> pools = getMemoryPoolMXBeans();
for (MemoryPoolMXBean p : pools) {
if (heapPool == null
&& p.getType() == MemoryType.HEAP
&& p.isUsageThresholdSupported()
&& p.isCollectionUsageThresholdSupported()) {
heapPool = new ObjectName(MEMORY_POOL_MXBEAN_DOMAIN_TYPE + ",name=" + p.getName());
}
if (nonHeapPool == null
&& p.getType() == MemoryType.NON_HEAP
&& p.isUsageThresholdSupported()) {
nonHeapPool = new ObjectName(MEMORY_POOL_MXBEAN_DOMAIN_TYPE + ",name=" + p.getName());
}
}
// Check notification emitters
MyListener listener = new MyListener();
server.addNotificationListener(memory, listener, null, null);
server.removeNotificationListener(memory, listener);
checkEnum();
checkList();
checkMap();
checkMemoryUsage();
checkThreadInfo();
checkOS();
checkSunGC();
System.out.println("Test passed.");
}