------------Original Message------------
From: "Ron Bodkin" <rbodkin@xxxxxxxxxxxxxx>
To: aspectj-users@xxxxxxxxxxx
Date: Wed, Sep-6-2006 10:56 AM
Subject: RE: [aspectj-users] Overriding
pointcuts
Savita you can significantly reduce the
overhead by dynamically enabling and disabling your aspects. This can be as
simple as using the if pointcut like so
public aspect
FlightRecorder {
private static boolean enabled; // can be controlled through JMX, for example
public pointcut flightMethod():
execution(!@PrimitiveDataLoggerAnnotation public * *.Method*(..));
private pointcut recordedMethod(): if(enabled) && flightMethod();
before() : recordedMethod() { … }
after() : recordedMethod() { … }
}
AspectJ constructs join points lazily when
they are guarded like this, so you should see the runtime overhead as simply
the time for a single (inlined) if test. This is often desirable, especially if
you would like to be able to enable and disable recording at runtime. You can
also allow more dynamic scoping e.g., by package and class like with logging
frameworks, possibly also with a global enabled switch. AspectJ been tuned
significantly over the years to support efficiently running when aspects like
this are disabled, but certainly you should benchmark the overhead in your
case.
Ron
From: aspectj-users-bounces@xxxxxxxxxxx
[mailto:aspectj-users-bounces@xxxxxxxxxxx] On
Behalf Of Chandan, Savita
Sent: Wednesday, September 06,
2006 10:22 AM
To: aspectj-users@xxxxxxxxxxx
Subject: RE: [aspectj-users]
Overriding pointcuts
Mathew,
Thanks for your response. That's a bummer.
Lets look at the problem from a different vantage point.
What Iam trying to accomplish here
is turn off the flight recorder logging with some configuration, without
recompiling. I can do this by turning it off in the flight recorder, but then I
will be taking the hit of AspectJ framework ( creating JoinPoints etc), which I
dont want.
Rephrasing the question, Is it possible to
turnoff AspectJ framework in the code without recompiling, by an off/on switch?
Thanks,
Savita
From:
aspectj-users-bounces@xxxxxxxxxxx [mailto:aspectj-users-bounces@xxxxxxxxxxx] On Behalf Of Matthew Webster
Sent: Wednesday, September 06,
2006 3:18 AM
To: aspectj-users@xxxxxxxxxxx
Subject: Re: [aspectj-users]
Overriding pointcuts
Savita,
Unfortunately this won't work because you can
only extend abstract aspects so you cannot override the behaviour of an
existing woven concrete aspect. You can override a pointcut but only in a
sub-aspect:
public abstract aspect AbstractPrimitiveFlightRecorder {
protected pointcut myMethod() :
PrimitiveFlightRecorderPointcutLibrary.recordedMethod();
}
public aspect PrimitiveFlightRecorderAspect extends AbstractPrimitiveFlightRecorder
{
protected pointcut myMethod()
: execution(!@PrimitiveDataLoggerAnnotation public * *.Method*(..));
before (): myMethod()
{
System.out.println(">
PrimitiveFlightRecorderAspect.before() " + thisJoinPoint);
}
after (): myMethod()
{
System.out.println("<
PrimitiveFlightRecorderAspect.before() " + thisJoinPoint);
}
}
However one solution is to use a separate
pointcut library which is used to weave at compile-time:
public aspect PrimitiveFlightRecorderPointcutLibrary {
protected pointcut recordedMethod() :
execution(@PrimitiveDataLoggerAnnotation public *
*.Method*(..));
}
public aspect PrimitiveFlightRecorderAspect
{
protected pointcut myMethod() :
PrimitiveFlightRecorderPointcutLibrary.recordedMethod();
before (): myMethod()
{
System.out.println(">
PrimitiveFlightRecorderAspect.before() " + thisJoinPoint);
}
after (): myMethod()
{
System.out.println("<
PrimitiveFlightRecorderAspect.before() " + thisJoinPoint);
}
}
Then for LTW substitute an alternative
implementation of the library. Because _all_ aspects must be woven, including
those woven previously, you will pick up the new pointcut definition.
Unfortunately you cannot define pointcut libraries using XML.
Matthew Webster
AOSD Project
Java Technology Centre, MP146
IBM Hursley
Park, Winchester, SO21 2JN,
England
Telephone: +44 196 2816139 (external) 246139 (internal)
Email: Matthew Webster/UK/IBM @ IBMGB, matthew_webster@xxxxxxxxxx
http://w3.hursley.ibm.com/~websterm/[1]
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"Chandan,
Savita" <Savita.Chandan@xxxxxxxxxxxxxx>
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06/09/2006 02:43
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[aspectj-users]
Overriding pointcuts
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Hi,
I want to override pointcuts inserted in the
aspect code during compile, at run time. What would I do to achieve this? If I
created a pointcut in aop.xml that contradicts the pointcut inserted in the
code, what would happen?
For ex.
In my aspect class
public aspect PrimitiveFlightRecorderAspect
{
pointcut myMethod():
execution(@ PrimitiveDataLoggerAnnotation public * *.Method*(..)) );
before (): myMethod() {
}
after (): myMethod() {}
}
Now if in the aop.xml if I were to do this.
(pardon me for any mistakes in the aop.xml, this is the first time I creating
one) what would happen?
<aspectj>
<aspects>
<aspect name="PrimitiveFlightRecorderAspect"/>
pointcut myMethod(): execution(! @ PrimitiveDataLoggerAnnotation public * *.Method*(..)) );
</aspects>
</aspectj>
Thanks,
Savita _______________________________________________
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