JvmPauseMonitor (Alluxio Core - Common Utilities 295 API)

java.lang.Object
- alluxio.util.JvmPauseMonitor

```
@NotThreadSafe
public class JvmPauseMonitor
extends java.lang.Object
```
Class to monitor JVM with a daemon thread, the thread sleep period of time and get the true time the sleep takes. If it is longer than it should be, the JVM has paused processing. Then log it into different level.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class JvmPauseMonitor.GarbageCollectorMXBeanView
An unmodifiable view of a garbage collector MX Bean.

Constructor Summary

Constructors
Constructor Description

JvmPauseMonitor(long gcSleepIntervalMs, long warnThresholdMs, long infoThresholdMs)
Constructs JvmPauseMonitor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`long`	`getInfoTimeExceeded()`
`long`	`getTotalExtraTime()`
`long`	`getWarnTimeExceeded()`
`boolean`	`isStarted()`
`void`	`start()`	Starts jvm monitor thread.
`void`	`stop()`	Stops jvm monitor.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - JvmPauseMonitor
```
public JvmPauseMonitor(long gcSleepIntervalMs,
                       long warnThresholdMs,
                       long infoThresholdMs)
```
    Constructs JvmPauseMonitor.
    
    Parameters:
    
    gcSleepIntervalMs - The time in milliseconds to sleep for in checking for GC pauses
    
    warnThresholdMs - when gc pauses exceeds this time in milliseconds log WARN
    
    infoThresholdMs - when gc pauses exceeds this time in milliseconds log INFO
- Method Detail
  - start
```
public void start()
```
    Starts jvm monitor thread.
  - stop
```
public void stop()
```
    Stops jvm monitor.
  - isStarted
```
public boolean isStarted()
```
    Returns:
    
    true if thread started, false otherwise
  - getWarnTimeExceeded
```
public long getWarnTimeExceeded()
```
    Returns:
    
    time exceeds WARN threshold in milliseconds
  - getInfoTimeExceeded
```
public long getInfoTimeExceeded()
```
    Returns:
    
    time exceeds INFO threshold in milliseconds
  - getTotalExtraTime
```
public long getTotalExtraTime()
```
    Returns:
    
    Total extra time in milliseconds