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https://issues.apache.org/jira/browse/AMQ-6252?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Timothy Bish resolved AMQ-6252.
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Resolution: Fixed
Assignee: Timothy Bish
Fix Version/s: 5.13.3
5.14.0
Fixed thread safety issues and added new method healthStatus that will return a
health status string after calling healthList. This preserves the existing
behavior so we don't break anyone while giving you a better entry into the
health information in a poller use case.
> HealthView has a variety of weaknesses
> --------------------------------------
>
> Key: AMQ-6252
> URL: https://issues.apache.org/jira/browse/AMQ-6252
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.9.1, 5.13.2
> Reporter: james
> Assignee: Timothy Bish
> Priority: Minor
> Fix For: 5.14.0, 5.13.3
>
>
> The HealthView utility has a variety of weaknesses.
> * The currentState field should be volatile to ensure correct visibility in a
> multi-threaded environment
> * the assignment to the currentState field at the end of the healthList
> method should only happen once the _final_ string has been built. the
> current code could expose a caller to a partially built string (since the
> field is continually re-assigned as the string is built).
> On a separate note, the semantics of this class are non-obvious. We were
> monitoring our broker via jmx using the CurrentState attribute for a year or
> so now and i only just realized that the value is useless. The value is
> useless because _it is only updated if you call the healthList() method
> first_. The CurrentState attribute is the one someone would most likely
> monitor using an external automated management product, yet it is not useful
> by itself. I would recommend one of the following approaches:
> * at the very least, the current behavior should be _clearly documented_ so
> that users know they have to call one of the other methods first in order to
> get a valid CurrentState
> * Alternately, it would be nice if calling the getCurrentState() by itself
> were sufficient. this could be accomplished via one of the following
> approaches:
> ** Have the BrokerService schedule a periodic task to invoke the healthList()
> method in order to ensure that the CurrentState attribute gets updated.
> ** Track a "last updated" field within the HealthView class and have the
> getCurrentState() method itself invoke the healthList() method first if the
> currentState is too old.
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