June 2002
Intermediate to advanced
312 pages
9h 18m
English
Content preview from Java Management ExtensionsBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Gauge Monitors
As we mentioned in the beginning of this chapter, a gauge monitor is used to monitor an MBean attribute that is:
Arbitrarily changing in any direction (i.e., up or down)
One of the Java floating-point types (
floatordouble) or one of the corresponding JDK wrapper classes (FloatorDouble)
In this section, we will look at the agent code that shows how to use
a gauge monitor. When using a gauge monitor, the first thing to do is
to create a new instance of the GaugeMonitor
class:
GaugeMonitor monitor = new GaugeMonitor( );
After that, the following attributes of the gauge monitor must be set:
ObservedObjectObservedAttributeNotifyHigh(must be set totrueif a notification is to be sent when the derived gauge exceeds the high threshold)NotifyLow(must be set totrueif a notification is to be sent when the derived gauge drops below the low threshold)HighThresholdLowThresholdGranularityPeriod
We discussed these attributes earlier in this chapter. Recall that a
notification is sent when the derived gauge exceeds the value of
HighThreshold (if NotifyHigh
has been explicitly set to true) or when the
derived gauge drops below the value of
LowThreshold (if NotifyLow is
set to true). The following example shows how to
create an instance of the gauge monitor, set its properties, register
the gauge monitor MBean with the MBean server, and start the
monitor’s thread of execution:
ObjectName queueObjName = new ObjectName(":name=Queue"); GaugeMonitor monitor = new GaugeMonitor( ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.