[jira] [Commented] (GEODE-7531) PoolManagerImpl.unregister(:Pool) naively assumes all Pool object instances are PoolImpls

["John Blum (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GEODE-7531?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16988096#comment-16988096 ] 

John Blum commented on GEODE-7531:
----------------------------------

This [change|https://github.com/apache/geode/blob/rel/v1.10.0/geode-core/src/main/java/org/apache/geode/internal/cache/PoolManagerImpl.java#L169-L174] (from this [commit|https://github.com/apache/geode/commit/51dd01cf309f1fccea9fe41e08fab42ed9759e52#diff-8d7c80296713855c7f737671ad251e9a]) would have been better designed and implemented with something like the following:

1) On the {{Pool}} interface, declare a {{isInUse():boolean}} method.

{code:java}
interface Pool {

  boolean isInUse();

  ...
}
{code}


Then, in the {{PoolManagerImpl}} class, rather than exposing the internal implementation of {{PoolImpl}} for "how" a {{Pool's}} usage is tracked (i.e. with an {{attacheCount}} property and an {{AtomicInteger}}, as seen [here|https://github.com/apache/geode/blob/rel/v1.10.0/geode-core/src/main/java/org/apache/geode/cache/client/internal/PoolImpl.java#L1113-L1141] and [here|https://github.com/apache/geode/blob/rel/v1.10.0/geode-core/src/main/java/org/apache/geode/cache/client/internal/PoolImpl.java#L1102-L1108]),  the {{PoolManagerImpl}} can strictly adhere to the interface (this is what is referred to as "_programming to interfaces_", the "contract", and not the implementation).

{code:java}
if (pool.isInUse()) {
    throw new IllegalStateException("Pool could not be destroyed because it is still in use!");
}
{code}

I'd also argue that the original message stating "how many" Regions is useless information actually:

{code:java}
 throw new IllegalStateException(String.format("Pool could not be destroyed because it is still in use by %s regions", attachCount));
{code}

For debugging purposes, I'd rather know which Regions (by "name") were still use the `Pool`.

Furthermore, it is NOT only Regions that use a Pool.  It is also CQs and Functions, etc.

Also, 1 could argue that registering and unregistering a {{Pool}} to be "managed" by a {{PoolManager}} is an independent concern of whether the {{Pool}} is in use or not.  However, "closing" a {{Pool}} (especially, prematurely) is certainly a "management" concern for {{Pools}} that are registered (i.e should be "managed") with a manager (a.k.a. {{PoolManager}}).

> PoolManagerImpl.unregister(:Pool) naively assumes all Pool object instances are PoolImpls
> -----------------------------------------------------------------------------------------
>
>                 Key: GEODE-7531
>                 URL: https://issues.apache.org/jira/browse/GEODE-7531
>             Project: Geode
>          Issue Type: Bug
>          Components: client/server
>    Affects Versions: 1.10.0
>         Environment: Apache Geode based applications on the JVM.
>            Reporter: John Blum
>            Priority: Blocker
>
> A recent [change|https://github.com/apache/geode/blob/rel/v1.10.0/geode-core/src/main/java/org/apache/geode/internal/cache/PoolManagerImpl.java#L169-L174] to the {{o.a.g.internal.cache.PoolManagerImpl}} class expects all {{o.a.g.cache.client.Pools}} registered with the {{o.a.g.cache.client.PoolManager}} to be {{o.a.g.cache.client.internal.PoolImp}} objects.
> This is certainly not going to be the case for Unit Tests that properly "mock" 1 or more {{Pool}} instances and additionally needs to register the mock {{Pool}} instances with the {{PoolManager}}.  While the later may not be as common for application code, it is more certainly common, and in some cases necessary, for framework or tooling code.



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