Hi Harsha,
Not a review either (at least not a complete one).
PlatformMBeanProviderImpl:
281 @Override
282 public Set<Class<? extends DynamicMBean>>
mbeanInterfaces() {
283 return Collections.emptySet();
284 }
For future maintainers, I think it would be good to copy
the comment at line 250 and insert it before line 283 too:
250 // DynamicMBean cannot be used to find an
MBean by ManagementFactory
HotSpotPerfCounterMBean:
Exception handling: I have the feeling that this part might
be a bit over-engineered. If you look at javax.management.StandardMBean
(which is a canonical implementation of DynamicMBean) and
then transitively at MBeanSupport and PerInterface where this class
eventually delegates to, you will see that:
1. You can throw NPE in setAttribute when attribute == null (no need for
all the wrapping)
2. You should throw AttributeNotFoundException when attempting to read
a write-only attribute or write a read-only attribute
3. You can throw NPE if AttributeList is null
179 String typeName = "java.lang.String";
That looks like a hack.
What if at some point the value of that attribute becomes non null,
and its class is *not* java.lang.String?
Then MBeanAttributeInfo would be lying.
If that ever happens - then it would be more consistent to coerce
the value to its declared type (String) before sending it as a
a result for getAttribute.
Or better, find a way to figure out what should be the class name
of the value even if the value is null (isn't there some metadata
available for these perf counters somewhere?).
PerfCounterMBeanTest:
testGetAttribute should verify that class of the returned value
corresponds to what was declared in the MBeanAttributeInfo for the
corresponding attribute.
cheers,
-- daniel
On 26/02/17 16:50, Harsha Wardhana B wrote:
Hi All,
Please review the below RFE,
JDK-8007141 <http://JDK-8007141> : Introduce Dynamic MBean exposing the
perf counters.
with webrev at,
http://cr.openjdk.java.net/~hb/8007141/webrev.00/
Appreciate if I can get inputs for below.
1. Location of HotSpotPerfCounterMBean. It is located at
src/jdk.management/share/classes/com/sun/management/internal. It can be
moved to src/jdk.management/share/classes/com/sun/management if required.
2. Javadoc comments for HotSpotPerfCounterMBean. Not sure if it is adequate.
3. Description for each attribute of MBean. I am using getUnits(),
getVariability(), and getFlags() for description. I am not sure if that
is the right description. Appreciate inputs from someone who knows perf
counters well.
Thanks
Harsha
