RFR: 7506: Incorrect numeric formatting of PID by JMC [v3]

[Brice Dutheil]

On Fri, 29 Mar 2024 02:57:30 GMT, Suchita Chaturvedi <schaturvedi at openjdk.org> wrote:

>> This PR is to fix the formatting issue of the JVM PID on JVM information screen. JVM PID attribute is received as NUMBER from JFR and hence the JMC application is treating is as number. When the number is smaller , the PID is displayed using commas and when the number is larger, its converted to exponential format. This is a long pending bug in product. 
>> 
>> As part of this PR we have introduced a new aggregator JVM_PID_ID which will contain the value of Identifier in plain text format instead of number format. This new aggregator is displayed on JVM Information page so that formatting is not applied as per NUMBER formatting rules.
>> 
>> JVM PID before the change:
>> <img width="359" alt="image" src="https://github.com/openjdk/jmc/assets/11155712/2e2a238c-8160-4bd1-8285-fb2a7a4fb85c">
>> 
>> JVM PID after the change:
>> <img width="355" alt="image" src="https://github.com/openjdk/jmc/assets/11155712/92668a9d-6053-4fa1-bcd0-7face596bc15">
>> 
>> The issue is more prominent when the identifier value is converted to exponential.
>
> Suchita Chaturvedi has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Used changed pid datatype from NUMBER to LONG as per review comment

This mostly looks good to me. Maybe add a log when the pid is encountered twice and if it changes.

core/org.openjdk.jmc.common/src/main/java/org/openjdk/jmc/common/item/Aggregators.java line 1068:

> 1066: 					Iterator<?> itr = source.iterator();
> 1067: 					while (itr.hasNext()) {
> 1068: 						value = (Long) itr.next();

**question:** Should there be at least a log if the value is seen more than once ?

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Marked as reviewed by bdutheil (Committer).

PR Review: https://git.openjdk.org/jmc/pull/557#pullrequestreview-2063119965
PR Review Comment: https://git.openjdk.org/jmc/pull/557#discussion_r1604832497