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https://issues.apache.org/jira/browse/MRESOLVER-278?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17617860#comment-17617860
]
ASF GitHub Bot commented on MRESOLVER-278:
------------------------------------------
cstamas commented on code in PR #201:
URL: https://github.com/apache/maven-resolver/pull/201#discussion_r995932176
##########
maven-resolver-api/src/main/java/org/eclipse/aether/DefaultRepositorySystemSession.java:
##########
@@ -873,4 +888,41 @@ public Collection<FileTransformer>
getTransformersForArtifact( Artifact artifact
}
}
+ private final CopyOnWriteArrayList<Consumer<RepositorySystemSession>>
onCloseHandlers
+ = new CopyOnWriteArrayList<>();
+
+ @Override
+ public void addOnCloseHandler( Consumer<RepositorySystemSession> handler )
+ {
+ verifyStateForMutation();
+ requireNonNull( handler, "handler cannot be null" );
+ onCloseHandlers.add( 0, handler );
Review Comment:
It is FILO, or what do you mean? List is populated in "reverse" order while
processed (handlers triggered) in "normal" order (from apsect of the List) =>
FILO - last triggered handler is first added.
> BREAKING: Make Session extend AutoCloseable (and introduce onCloseHandlers)
> ---------------------------------------------------------------------------
>
> Key: MRESOLVER-278
> URL: https://issues.apache.org/jira/browse/MRESOLVER-278
> Project: Maven Resolver
> Issue Type: New Feature
> Components: Resolver
> Reporter: Tamas Cservenak
> Assignee: Tamas Cservenak
> Priority: Major
> Fix For: 1.9.0
>
>
> So far, in (vanilla) Maven, the lifecycle of session was on par with
> lifecycle of SISU container, as Maven does something like this:
> * boot, create container
> * create session
> * work
> * destroy container
> * exit JVM
> So, Maven execution is 1 session 1 container, are on par.
> This is not true for cases where container (and resolver components) are
> reused across several sessions, like mvnd does. Also, current code on master
> (named locks adapter) uses {{@PreDestroy}} to shut down adapters, that is
> invoked when container is shut down, while the adapters are created
> per-session. This means that long-living mvnd daemons will shut down the
> unused adapter only when daemon itself is shut down, even is session for
> which adapter was created is long gone/done.
> While Maven has "session scoped" notion, resolver has not. Hence, simplest
> and cleanest solution is to make RepositorySystemSession have a method to
> "close", denoting that "this session is done". Also, if we can provide hooks
> for "onSessionClose", this resolves all the problems, as for example the
> adapter, that is created per session, could be now cleanly shut down at
> session end.
> One gotcha: this change implies a {*}breaking change for integrators of
> resolver{*}: integrator should make sure they close the session after they
> are done with it.
> Example changes needed for resolver users:
> [https://github.com/apache/maven/pull/822]
> The "pattern" to make use of this feature in resolver is following:
> * stuff something into session data, ideally using computeWhenAbsent
> * if absent, register a callback hook as well
> * in callback, get the stuffed thing from session and if present, do
> something with it
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