...
The
...
purpose
...
of
...
this
...
article
...
is
...
to
...
show
...
the
...
possibilities
...
of
...
server-side
...
monitoring
...
using
...
Geronimo,
...
a
...
Java
...
TM 2
...
Platform
...
Enterprise
...
Edition
...
(J2EE)
...
application
...
server.
...
Monitoring
...
an
...
application
...
server
...
from
...
inside
...
saves
...
network
...
traffic,
...
since
...
monitored
...
information
...
can
...
be
...
analyzed,
...
filtered,
...
summarized,
...
and
...
set
...
into
...
an
...
application
...
specific
...
context
...
inside
...
the
...
server.
...
For
...
example
...
an
...
application
...
server
...
could
...
send
...
an
...
...
when
...
the
...
response
...
time
...
of
...
our
...
online
...
shop
...
gets
...
unacceptable
...
big.
...
A
...
simple
...
web
...
application
...
has
...
been
...
used
...
to
...
develop
...
a
...
server-side
...
monitoring
...
component
...
that
...
monitors
...
three
...
servlets
...
and
...
gives
...
alarm
...
when
...
the
...
overall
...
average
...
processing
...
time
...
exceeds
...
a
...
certain
...
given
...
threshold.
...
What
...
is
...
needed
...
Anchor | ||||
---|---|---|---|---|
|
- JDK 5.0
...
- (because
...
- of
...
- the
...
- used
...
- JConsole
...
- tool;
...
- it
...
- is
...
- not
...
- included
...
- in
...
- JDK1.4):
...
...
- Standard Geronimo:
...
...
- Sample
...
- Code:
...
...
- (Contents:
...
- Sources,
...
- shell
...
- scripts,
...
- archives,
...
- README,
...
- etc.)
...
Introduction
A lot of articles can be found in managing application servers with remote clients using the Java Management Extensions (JMX; http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/
...
).
...
These
...
management
...
client
...
applications
...
describe
...
how
...
to
...
connect
...
management
...
clients
...
to
...
a
...
server
...
and
...
how
...
to
...
retrieve
...
information
...
from
...
the
...
server
...
applications.
...
While
...
much
...
attention
...
has
...
been
...
given
...
to
...
the
...
client-side
...
aspects
...
of
...
JMX,
...
very
...
little
...
consideration
...
has
...
been
...
given
...
to
...
the
...
server-side
...
challenges
...
of
...
developing
...
and
...
deploying
...
management
...
beans
...
(MBeans).
...
The
...
reason
...
lays
...
in
...
the
...
difficulties
...
of
...
development
...
and
...
integration
...
of
...
such
...
components.
...
Often
...
it
...
is
...
not
...
possible
...
at
...
all.
...
With
...
the
...
appearance
...
of
...
Geronimo
...
the
...
server-side
...
monitoring
...
by
...
implementing
...
MBeans
...
for
...
monitoring
...
servlets
...
or
...
EJBs
...
is
...
simplified.
...
This
...
article
...
shows
...
how
...
to
...
monitor
...
the
...
application
...
server
...
Geronimo
...
from
...
inside
...
and
...
how
...
detailed
...
information
...
querying
...
the
...
MBeans
...
can
...
be
...
analyzed,
...
grouped
...
and
...
generated
...
to
...
meta
...
data
...
inside
...
the
...
server.
...
This
...
saves
...
bandwidth
...
between
...
the
...
management
...
client
...
and
...
the
...
server
...
and
...
allows
...
to
...
build
...
a
...
more
...
efficient
...
controlled
...
application
...
server
...
with
...
the
...
monitor
...
component
...
inside.
...
To
...
keep
...
it
...
simple
...
the
...
Geronimo
...
monitoring
...
component
...
is
...
investigating
...
the
...
processing
...
time
...
of
...
three
...
servlets.
...
The
...
average
...
of
...
all
...
three
...
processing
...
times
...
is
...
built
...
and
...
an
...
alarm
...
is
...
generated
...
if
...
the
...
overall
...
processing
...
time
...
is
...
greater
...
then
...
a
...
pre-defined
...
value.
...
How
...
the
...
developed
...
monitoring
...
component
...
is
...
integrated
...
into
...
the
...
Geronimo
...
architecture
...
and
...
how
...
it
...
is
...
deployed
...
and
...
managed
...
by
...
the
...
JConsole
...
http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/
...
is
...
content
...
of
...
this
...
paper.
...
Overview
...
about
...
MBeans
...
and
...
GBeans
...
This
...
section
...
gives
...
a
...
short
...
introduction
...
of
...
the
...
management
...
standard
...
JMX
...
(
...
http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/
...
)
...
with
...
its
...
fundamental
...
beans,
...
the
...
MBeans.
...
It
...
explains
...
that
...
Geronimo
...
can
...
be
...
extended
...
by
...
new
...
components,
...
if
...
they
...
are
...
GBeans.
...
Java
...
Management
...
Extension
...
Java
...
Management
...
eXtension
...
(JMX)
...
(
...
http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/
...
)
...
standardizes
...
the
...
managing
...
and
...
monitoring
...
of
...
applications
...
and
...
services.
...
It
...
enables
...
developers
...
to
...
write
...
management
...
programs
...
for
...
their
...
applications
...
in
...
a
...
vendor/neutral
...
fashion.
...
Another
...
important
...
standard
...
in
...
the
...
area
...
of
...
J2EE
...
is
...
JSR-77
...
(
...
http://jcp.org/en/jsr/detail?id=77
...
).
...
JSR-77
...
is
...
a
...
standard
...
model
...
for
...
managing
...
the
...
J2EE
...
platform
...
and
...
allows
...
application
...
server
...
vendors
...
to
...
present
...
performance
...
metrics
...
in
...
a
...
standard
...
way.
...
It
...
defines
...
a
...
set
...
of
...
standard
...
metric
...
types
...
that
...
can
...
be
...
used
...
to
...
monitor
...
J2EE
...
platforms.
...
The
...
following
...
types
...
of
...
metrics
...
are
...
defined
...
in
...
JSR-77:
...
range
...
statistics,
...
boundary
...
statistics,
...
bounded
...
range
...
statistics,
...
count
...
statistics,
...
and
...
time
...
statistics.
...
Fundamental
...
to
...
JMX
...
is
...
the
...
management
...
bean,
...
MBean.
...
There
...
are
...
four
...
types
...
of
...
MBeans
...
(Standard,
...
Dynamic,
...
Model,
...
Open),
...
and
...
each
...
provide
...
a
...
different
...
level
...
of
...
sophistication
...
for
...
management
...
and
...
monitoring
...
(see
...
http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/
...
for
...
more
...
details).
...
In
...
this
...
paper,
...
MBeans
...
are
...
used
...
for
...
the
...
monitoring
...
of
...
servlets
...
and
...
for
...
controlling
...
the
...
GBean
...
monitor
...
component.
...
Geronimo
...
hosting
...
our
...
Monitor
...
Component
...
Geronimo
...
is
...
in
...
the
...
first
...
place
...
a
...
Java
...
TM 2
...
Platform
...
Enterprise
...
Edition
...
(J2EE)
...
application
...
server,
...
but
...
can
...
be
...
seen
...
as
...
a
...
general
...
service
...
container.
...
The
...
main
...
focus
...
of
...
developing
...
Geronimo
...
was
...
the
...
managing
...
and
...
scaling
...
of
...
application
...
servers.
...
Geronimo's
...
intention
...
was
...
never
...
to
...
re-implement
...
a
...
servlet
...
or
...
an
...
EJB
...
container,
...
but
...
to
...
use
...
existing
...
open
...
source
...
applications
...
(mainly
...
from
...
Apache
...
...
)
...
whenever
...
possible,
...
plug
...
it
...
together
...
and
...
build
...
a
...
new
...
application
...
server.
...
Anchor | ||||
---|---|---|---|---|
|
The standard Geronimo distribution comes with Apache Tomcat http://tomcat.apache.org/
...
and
...
EJB
...
container
...
(OpenEJB
...
http://incubator.apache.org/openejb/
...
)
...
component.
...
Extending
...
Geronimo
...
by
...
a
...
monitoring
...
component,
...
developed
...
for
...
this
...
paper,
...
is
...
like
...
Tomcat,
...
or
...
any
...
other
...
component
...
as
...
long
...
as
...
they
...
are
...
GBeans,
...
as
...
shown
...
in
...
the
...
Figure:
...
...
...
...
...
...
...
.
...
The
...
fundamental
...
entity
...
within
...
Geronimo
...
are
...
Geronimo
...
Beans
...
(GBeans).
...
Geronimo
...
Beans
...
Anchor | ||||
---|---|---|---|---|
|
Everything in Geronimo is basically a Geronimo Bean (GBean).
...
Geronimo's
...
kernel
...
handles
...
these
...
GBeans
...
and
...
stores
...
them
...
in
...
it
...
s
...
repository.
...
By
...
default
...
Geronimo
...
uses
...
not
...
a
...
database
...
but
...
a
...
file
...
directory
...
named
...
repository
...
.
...
Anchor | ||||
---|---|---|---|---|
|
Users can install their own GBeans by describing them with a deployment plan and deploy them into Geronimo by using the GBeanBuilder (see Fig. #Geronimo GBeans). Every GBean must implement the
GBeanLifecycle
interface. This interface defines three methods: doStart()
, doStop()
, doFail()
as you see in the class diagram (Fig. #Class diagram of the management component example). The GBeanLifecycle
interface is the contract between the Geronimo plug-in framework and our application, the GBean. The Geronimo framework uses dependency injection (see Fowler: Inversion of control containers and the dependency injection pattern, Frod: Dependency injection in apache geronimo, part 1, Dependency injection in apache geronimo, part 2) to set GBean parameters during the deployment process. There are two ways to inject information during the deployment process of GBeans:- getter/setter injection: framework injects information using the setter and getter methods of the GBean.
- constructor injection: framework injects information using the constructor of the GBean, when it is instantiated.
The example of this article is using constructor injection to pass the servlet MBean names and the MBean server reference to the monitor GBean.
The Server-Side Monitor Component
Subject of the section is a detailed architecture description of how the GBeans and MBeans are interacting. Discussed are the developed monitor classes and how to deploy the monitor component into Geronimo. Finally the monitor component is tested using the JConsole.
Geronimo Architecture Overview
First an overview about the integration of the monitor component into Geronimo's architecture is given in Figure #Geronimo architecture with integrated monitor component. It shows the JMX-Layer with the MBeanServer and the MBeans, the Tomcat component and the monitor component.
Anchor | ||||
---|---|---|---|---|
|
Geronimo registers each GBean as a MBean with the MBean Server, when the server is started. Tomcat http://tomcat.apache.org/
...
,
...
for
...
example,
...
consists
...
of
...
several
...
GBeans
...
and
...
therefore
...
consists
...
of
...
several
...
MBeans
...
(TomcatWebContainer,
...
TomcatWebConnector,
...
TomcatEngine,
...
TomcatJAASRealm,
...
etc.).
...
For
...
each
...
servlet
...
(S1,
...
S2,
...
S3)
...
in
...
Fig.
...
...
...
...
...
...
...
there
...
exists
...
a
...
MBean
...
(MB
...
S1,
...
MB
...
S2,
...
MB
...
S3)
...
with
...
information
...
defined
...
in
...
the
...
JSR-77
...
specification.
...
The
...
dashed
...
line
...
objects
...
are
...
instantiated,
...
when
...
the
...
sample
...
monitor
...
component
...
(Servlet
...
Monitor
...
GBean)
...
is
...
deployed
...
into
...
Geronimo
...
using
...
the
...
"GBean
...
Builder".
...
The
...
MBeanServerKernelBridge
...
registers
...
each
...
loaded
...
GBean
...
as
...
a
...
MBean
...
(MB
...
MC)
...
at
...
the
...
MBean
...
server.
...
The
...
instantiated
...
thread
...
(T
...
C)
...
retrieves
...
information
...
from
...
the
...
servlet
...
MBeans
...
(MB
...
S1,
...
MB
...
S2,
...
MB
...
S3).
...
Servlets
...
under
...
observation
...
It
...
is
...
not
...
the
...
content
...
of
...
this
...
article
...
to
...
show
...
how
...
to
...
develop
...
and
...
deploy
...
servlets.
...
There
...
is
...
a
...
simple
...
security
...
servlet
...
example
...
in
...
Geronimo's
...
user
...
guide
...
http://cwiki.apache.org/GMOxDOC11/apache-geronimo-v11-users-guide.html
...
,
...
if
...
you
...
want
...
to
...
know
...
more
...
about
...
web
...
application
...
in
...
Geronimo.
...
When
...
you
...
unpack
...
the
...
sources
...
(found
...
in
...
Section
...
...
...
...
)
...
and
...
follow
...
the
...
included
...
Readme
...
file
...
you
...
can
...
deploy
...
a
...
web
...
application
...
consisting
...
of
...
3
...
simple
...
servlets
...
(ServletStatistic,
...
ServeletData,
...
ServletSystemTime).
...
Now
...
you
...
should
...
be
...
able
...
to
...
call
...
the
...
servlets.
...
For
...
example:
...
http://localhost:8080/mysample/app1/ServletSystemTime
...
.
...
Server-Side
...
Monitor
...
Component
...
The
...
server-side
...
monitor
...
component
...
consists
...
of
...
2
...
classes
...
(see
...
Fig.
...
...
...
...
...
...
...
...
):
...
- the
...
- \verb+ServletMonitorGBean+,
...
- which
...
- implements
...
- the
...
GBeanLifecyle
...
- interface
...
- and
...
- the
...
- \verb+AverageBuilder
...
- +
...
- thread,
...
- which
...
- is
...
- doing
...
- the
...
- actual
...
- collection
...
- of
...
- data
...
- from
...
- the
...
- servlet
...
- MBeans.
...
- If
...
- the
...
- calculated
...
- average
...
- processing
...
- time
...
- is
...
- above
...
- the
...
- threshold
...
- an
...
- alarm
...
- is
...
- generated.
...
- The
...
- alarming
...
- function
...
- is
...
- not
...
- sending
...
- an
...
- e-mail,
...
- it
...
- is
...
- only
...
- logging
...
- "ALARM"
...
- to
...
- keep
...
- the
...
- code
...
- simple.
Anchor | ||||
---|---|---|---|---|
|
The Monitor GBean
The Geronimo framework is injecting information about the MBean server reference and the MBean servlet object names into the constructor during deployment. Listing {#Listing 1] shows you how to inform the Geronimo kernel about the ability of the GBean. The GBeanInfoBuilder
is used to tell Geronimo the name of the GBean class. Then the constructor injection is defined by addAttribute
to specify the three servlet MBean names, addReference
to specify the MBean server reference, and setConstructor
to specify the constructor call.
Anchor | ||||
---|---|---|---|---|
|
Code Block | ||||
---|---|---|---|---|
| ||||
{anchor:Class diagram of the management component example} !ClassDiagram.jpg! h3. The Monitor GBean The Geronimo framework is injecting information about the MBean server reference and the MBean servlet object names into the constructor during deployment. Listing {#Listing 1\] shows you how to inform the Geronimo kernel about the ability of the GBean. The {{GBeanInfoBuilder}} is used to tell Geronimo the name of the GBean class. Then the constructor injection is defined by {{addAttribute}} to specify the three servlet MBean names, {{addReference}} to specify the MBean server reference, and {{setConstructor}} to specify the constructor call. {anchor:Listing 1} {code:title=ServletMonitorGBean.java (cutout)|borderStyle=solid} public static final GBeanInfo GBEAN_INFO; static { GBeanInfoBuilder infoB = GBeanInfoBuilder.createStatic("ServletMonitorGBean", ServletMonitorGBean.class); infoB.addAttribute("servletName1", String.class, true); infoB.addAttribute("servletName2", String.class, true); infoB.addAttribute("servletName3", String.class, true); infoB.addReference("MBeanServerReference", MBeanServerReference.class); infoB.setConstructor(new String[] { "MBeanServerReference", "servletName1", "servletName2", "servletName3"}); {code} |
Further
...
we
...
want
...
the
...
methods,
...
startCalcAverage
...
,
...
stopCalcAverage
...
,
...
defineThreshold
...
and
...
defineUpdateInterval
...
to
...
be
...
available
...
by
...
an
...
JMX
...
management
...
client.
...
This
...
allows
...
us
...
to
...
interact
...
with
...
the
...
monitor
...
component
...
through
...
a
...
MBean
...
using
...
the
...
JConsole
...
as
...
shown
...
in
...
Section
...
...
...
...
...
.
...
Publishing
...
GBean
...
methods
...
through
...
a
...
MBean
...
is
...
done
...
by
...
the
...
addOperation
...
of
...
the
...
GBeanInfoBuilder
...
by
...
specifying
...
the
...
method
...
names
...
and
...
parameters,
...
as
...
seen
...
in
...
Listing
...
...
...
:
Anchor | ||||
---|---|---|---|---|
|
Code Block | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
|
|
| |
| =
| |||||||
} infoB.addOperation("startCalcAverage"); infoB.addOperation("stopCalcAverage"); infoB.addOperation("defineThreshold",new Class[]{int.class}); infoB.addOperation("defineUpdateInterval",new Class[]{int.class}); {code} |
The
...
MBean
...
configuration
...
process
...
is
...
finished
...
by
...
setting
...
the
...
variable
...
GBEAN_INFO
...
.
...
Thus
...
the
...
MBeanServerKernelBridge
...
can
...
use
...
getGBeanInfo()
...
to
...
get
...
a
...
GBeanInfo
...
object
...
(Listing
...
...
...
)
...
with
...
the
...
MBean
...
configuration
...
and
...
builds
...
the
...
appropriate
...
MBean
...
MB
...
MC Figure:
...
...
...
...
...
...
Anchor | ||||
---|---|---|---|---|
|
Code Block | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
|
|
| |
| =
| |||||||
} GBEAN_INFO = infoB.getBeanInfo(); public static GBeanInfo getGBeanInfo() { return GBEAN_INFO; } {code} h3. The AverageBuilder Thread The {{AverageBuilder}} class |
The AverageBuilder Thread
The AverageBuilder
class (Fig.
...
...
...
...
...
...
...
...
)
...
is
...
a
...
thread
...
which
...
is
...
querying
...
the
...
servlet
...
MBeans.
...
To
...
query
...
information
...
from
...
servlet
...
MBeans,
...
like
...
the
...
requestCounter
...
,
...
you
...
have
...
to
...
know
...
the
...
object
...
name
...
of
...
the
...
MBean.
...
You
...
can
...
find
...
out
...
about
...
the
...
object
...
name
...
using
...
a
...
JMX
...
management
...
client.
...
In
...
the
...
section,
...
...
...
...
...
...
,
...
it
...
is
...
shown
...
how
...
to
...
find
...
out
...
about
...
the
...
object
...
names
...
of
...
the
...
servlet
...
MBeans.
...
Since
...
we
...
injected
...
this
...
information
...
during
...
the
...
deployment
...
process
...
of
...
the
...
GBean,
...
we
...
are
...
not
...
to
...
worry
...
about
...
that
...
at
...
the
...
moment.
...
Having
...
the
...
MBean
...
object
...
name
...
we
...
get
...
the
...
information
...
precessingTime
...
and
...
requestCount
...
as
...
follows
...
(see
...
Listing
...
...
...
):
Anchor | ||||
---|---|---|---|---|
|
Code Block | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
|
|
| |
| =
| |||||||
} ObjectName objNameStatisticServlet = ObjectName.getInstance(statisticServlet); ObjectName objNameDataServlet=ObjectName.getInstance(dataServlet); ObjectName objNameSystemTimeServlet = ObjectName.getInstance(systemTimeServlet); long pt1=((Long)mbserver.getAttribute(objNameStatisticServlet, "processingTime")).longValue(); int rc1=((Integer)mbserver.getAttribute(objNameStatisticServlet, "requestCount")).intValue(); {code} |
Doing
...
this
...
for
...
all
...
3
...
servlets
...
and
...
building
...
the
...
average
...
can
...
be
...
seen
...
in
...
the
...
source
...
code.
...
Deploying
...
the
...
Server-Side
...
Monitor
...
Component
...
When
...
the
...
GBean
...
monitor
...
component
...
is
...
compiled,
...
it
...
has
...
to
...
be
...
deployed
...
into
...
Geronimo.
...
For
...
deploying
...
the
...
monitor
...
component
...
everything
...
has
...
to
...
be
...
packaged
...
according
...
to
...
Geronimo
...
(see
...
Geronimo's
...
User
...
Guide
...
http://cwiki.apache.org/GMOxDOC11/apache-geronimo-v11-users-guide.html
...
).
...
That
...
means
...
you
...
have
...
to
...
pack
...
your
...
GBeans
...
with
...
a
...
deployment-plan
...
into
...
a
...
jar
...
file,
...
e.g.
...
SimpleServletMonitor-1.0.jar
...
and
...
deploy
...
it.
...
For
...
the
...
deployment,
...
we
...
have
...
chosen
...
the
...
java
...
deployment
...
program,
...
deployer:
Code Block |
---|
} java -jar $GERONIMOHOME/bin/deployer.jar --user system --password manager deploy SimpleServletMonitor-1.0.jar {code}jar |
It
...
is
...
a
...
lot
...
faster
...
using
...
the
...
deployer
...
program,
...
then
...
doing
...
all
...
the
...
clicking
...
using
...
Geronimo's
...
browser
...
based
...
management
...
tool
...
(
...
...
).
...
With
...
the
...
example
...
code,
...
there
...
comes
...
also
...
some
...
simple
...
Linux
...
shell
...
scripts
...
supporting
...
deployment,
...
un-deployment,
...
listing,
...
etc.
...
Anchor | ||||
---|---|---|---|---|
|
...
|
...
Deployment
...
Plans
...
for
...
Geronimo's
...
GBeans
...
Geronimo's
...
deployment
...
plans
...
(
...
geronimo-service.xml
...
)
...
state
...
information
...
about
...
GBean
...
names,
...
references
...
and
...
dependencies.
...
For
...
a
...
more
...
detailed
...
description
...
about
...
the
...
deployment
...
descriptor,
...
see
...
http://cwiki.apache.org/GMOxDOC11/apache-geronimo-v11-users-guide.html
...
.
...
Our
...
deployment
...
descriptor
...
(Listing
...
...
...
)
...
consists
...
of
...
an
...
<environment>
...
and
...
and
...
<gbean>
...
part:
Anchor | ||||
---|---|---|---|---|
|
Code Block | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
| |
| =
| ||||||
} <?xml version="1.0" encoding="UTF-8"?> <module xmlns="http://geronimo.apache.org/xml/ns/deployment-1.1"> <environment>...</environment> <gbean ...>...</gbean> </module> {code} h4. The |
The ``environment''
...
part:
...
We
...
have
...
to
...
give
...
our
...
monitor
...
GBean
...
an
...
unique
...
name
...
inside
...
Geronimo
...
by
...
defining
...
its
...
groupId
...
,
...
artifactId
...
,
...
version
...
and
...
type
...
.
...
Furthermore
...
we
...
have
...
to
...
define
...
<dependencies>
...
(see
...
Listing:
...
...
).
...
Because
...
we
...
want
...
to
...
inject
...
the
...
object
...
reference
...
for
...
MBeanServerReference
...
to
...
the
...
GBean
...
constructor
...
our
...
deployment
...
process
...
depends
...
on
...
the
...
geronimo/rmi-naming
...
defined
...
as
...
the
...
artifactId
...
in
...
the
...
geronimo-service.xml
...
.
...
The
...
serialized
...
version
...
of
...
that
...
reference
...
is
...
found
...
in
...
the
...
repository
...
under:
...
geronimo/rmi-naming
...
.
Anchor | ||||
---|---|---|---|---|
|
Code Block | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
| |
| =
| ||||||
} <environment> <moduleId> <groupId>mysample</groupId> <artifactId>SimpleServletMonitor</artifactId> <version>1.0</version> <type>car</type> </moduleId> <dependencies> <dependency> <groupId>geronimo</groupId> <artifactId>rmi-naming</artifactId> <type>car</type> </dependency> </dependencies> </environment> {code} h4. The |
The ``gbean''
...
part:
...
First
...
you
...
have
...
to
...
define
...
the
...
name
...
of
...
the
...
GBean
...
and
...
the
...
exact
...
class
...
name
...
as
...
XML
...
attributes
...
of
...
the
...
element
...
<gbean>
...
(see
...
Listing:
...
...
).
...
Then
...
you
...
define
...
all
...
the
...
references
...
and
...
attributes,
...
which
...
should
...
be
...
injected
...
during
...
deployment.
Anchor | ||||
---|---|---|---|---|
|
Code Block | |||||||||
---|---|---|---|---|---|---|---|---|---|
|
| |
| =
| ||||||
} <gbean name="ServletMonitorGBean" class="de.hsfurtwangen.informatik.ServletMonitorGBean"> <reference name="MBeanServerReference"> <name>MBeanServerReference</name> </reference> <attribute name="servletName1" type="java.lang.String"> Geronimo:j2eeType=Servlet,name=ServletStatistic,WebModule=//localhost/mysample,J2EEApplication=none,J2EEServer=none </attribute> <attribute name="servletName2" type="java.lang.String"> Geronimo:j2eeType=Servlet,name=ServletData,WebModule=//localhost/mysample,J2EEApplication=none,J2EEServer=none </attribute> <attribute name="servletName3" type="java.lang.String"> Geronimo:j2eeType=Servlet,name=ServletSystemTime,WebModule=//localhost/mysample,J2EEApplication=none,J2EEServer=none </attribute> </gbean> {code} |
As
...
seen
...
in
...
our
...
example
...
above
...
(Listing:
...
...
),
...
the
...
following
...
parameters
...
are
...
injected
...
by
...
constructor
...
injection
...
of
...
the
...
Geronimo
...
framework:
...
- MBeanServerReference:
...
- The
...
- corresponding
...
- source
...
- code
...
- in
...
- the
...
- GBean
...
- class
...
- is:
...
GBeanInfoBuilder.addReference("MBeanServerReference",MBeanServerReference.class)
...
- servleteName1:
...
- The
...
- corresponding
...
- source
...
- code
...
- in
...
- the
...
- GBean
...
- class
...
- is:
...
GBeanInfoBuilder.addAttribute("servletName1",String.class)
...
- servletName2:
...
- The
...
- corresponding
...
- source
...
- code
...
- in
...
- the
...
- GBean
...
- class
...
- is:
...
GBeanInfoBuilder.addAttribute("servletName2",String.class)
...
- servletName3:
...
- The
...
- corresponding
...
- source
...
- code
...
- in
...
- the
...
- GBean
...
- class
...
- is:
...
GBeanInfoBuilder.addAttribute("servletName3",String.class)
...
Testing the Monitor Component
Accessing Geronimo using JConsole
We want to use JConsole http://java.sun.com/j2se/1.5.0/docs/guide/management/jconsole.html
...
,
...
http://java.sun.com/j2se/1.5.0/docs/tooldocs/share/jconsole.html
...
,
...
which
...
is
...
a
...
JMX-compliant
...
GUI
...
tool
...
that
...
connects
...
to
...
a
...
running
...
JVM.
...
If
...
the
...
JAVA_HOME
...
environment
...
variable
...
is
...
set
...
to
...
a
...
JDK
...
5.0,
...
you
...
only
...
have
...
to
...
type
...
in:
...
Anchor | ||||
---|---|---|---|---|
|
To connect to your Geronimo server you have to use the following settings in your JConsole (see Fig. #JConsole):
- JMX URL:
service:jmx:rmi:///jndi/rmi://localhost:1099/JMXConnector
...
- User Name:
...
-
system
- Password:
manager
After the management client is connected to Geronimo you switch to the MBean view (see Fig. #Servlet MBean view) and navigate to one of the deployed servlets, e.g. ServletStatistic
(1st and 2nd figure of Fig. #Servlet MBean view).
Anchor | ||||
---|---|---|---|---|
|
One interesting information is the object name (3rd figure of Fig. #Servlet MBean view)) that is used in the deployment descriptor for Geronimo's GBean deployment plan (see section #Deployment Plans for Geronimo's GBeans).
Anchor | ||||
---|---|---|---|---|
|
Interacting with the Monitor Component: ServletMonitorGBean
First, navigate to the GBean (see Fig. #GBean Operations). Then you switch to the operations view. Now you have access to all the methods you defined in the GBean with \verb+GBeanInfoBuilder+. Let's start the process by calculating the average processing time of the 3 servlets. Just click on \verb+startCalcAverage()+
...
and
...
you
...
can
...
see
...
in
...
the
...
\verb+GERONIMO_HOME/var/log/geronimo.out+
...
file
...
that
...
the
...
averages
...
are
...
calculated.
...
Now
...
reload
...
the
...
servlets
...
several
...
times,
...
so
...
that
...
you
...
can
...
see
...
changes
...
in
...
the
...
output.
...
You
...
could
...
also
...
change
...
the
...
update
...
time
...
for
...
the
...
information
...
polling
...
of
...
the
...
servlets.
...
Click
...
first
...
on
...
\verb+parameter0+
...
and
...
set
...
the
...
value
...
to
...
5000
...
and
...
then
...
on
...
\verb+defineUpdateInterval+.
...
Now
...
every
...
5s
...
the
...
data
...
is
...
collected
...
from
...
the
...
servlets.
...
Play
...
around
...
and
...
have
...
fun.
...
Anchor | ||||
---|---|---|---|---|
|
Conclusion
An overview of the used technologies, Geronimo's GBeans and JMX has been given. You should now have an idea how to develop and deploy a monitor component inside Geronimo application server and how to improve the monitoring. The developed example shows a server's ability to do its own monitoring and application specific alarming. There are a lot more possibilities what can be done. For example a server could monitor the number of servlet requests and if there are more then, e.g. 20 per seconds, there might be a denial of service attack. Analyze the monitored data inside the server and optimize Geronimo's configuration, e.g. thread pool size. etc.
References
- Sun's java management extensions (JMX) page. http://java.sun.com/javase/technologies/core/mntr-mgmt/javamanagement/
...
- .
...
- JConsole
...
- reference.
...
...
- .
...
- JConsole
...
- manual.
...
...
- .
...
- JSR-77:
...
- J2EE
...
- management
...
- specification.
...
...
- .
...
- Apache
...
- home
...
- page.
...
...
- .
...
- Tomcat
...
- home
...
- page.
...
...
- .
...
- OpenEJB
...
- home
...
- page.
...
...
- .
...
- Martin
...
- Fowler;
...
- Inversion
...
- of
...
- control
...
- containers
...
- and
...
- the
...
- dependency
...
- injection
...
- pattern.
...
- ;
...
...
- ;
...
- January;
...
- 2004.
...
- Niel
...
- Frod;
...
- Dependency
...
- injection
...
- in
...
- apache
...
- geronimo,
...
- part
...
- 1:
...
- A
...
- new
...
- way
...
- to
...
- look
...
- at
...
- decoupling
...
- in
...
- j2ee
...
- applications.
...
- ;
...
...
- ;
...
- February;
...
- 2006.
...
- Niel
...
- Frod;
...
- Dependency
...
- injection
...
- in
...
- apache
...
- geronimo,
...
- part
...
- 2:
...
- The
...
- next
...
- generation.
...
- ;
...
...
- ;
...
- February;
...
- 2006.