[jira] [Commented] (KAFKA-20958) Introduce internal accessor pattern to encapsulate cross-package APIs

["Chia-Ping Tsai (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-20958?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18105573#comment-18105573 ] 

Chia-Ping Tsai commented on KAFKA-20958:
----------------------------------------


{code:java}
@InterfaceAudience.Public
public final class Metrics implements Closeable {

    // ...

    /**
     * @deprecated Since x.x.x. This constructor leaks the internal Time object. 
     *             Please use the public constructors that do not accept a Time object.
     *             Internal Kafka components should use {@link MetricsInternalFactory#create(Time)}.
     *             This constructor will be reduced to package-private visibility in version 5.0.
     */
    @Deprecated
    @SuppressKafkaInternalApiUsage("KIP-1311: Deprecated and will be hidden in 5.0")
    public Metrics(Time time) {
        this(new MetricConfig(), new ArrayList<>(0), time);
    }
{code}


{code:java}
// Some comments here
public String getFoo()
{
    return foo;
}
{code}



> Introduce internal accessor pattern to encapsulate cross-package APIs
> ---------------------------------------------------------------------
>
>                 Key: KAFKA-20958
>                 URL: https://issues.apache.org/jira/browse/KAFKA-20958
>             Project: Kafka
>          Issue Type: Improvement
>            Reporter: Chia-Ping Tsai
>            Assignee: Chia-Ping Tsai
>            Priority: Critical
>              Labels: need-kip
>
> Currently, to allow cross-package instantiation or state access for internal Kafka components, we either:
> # Leak internal classes (like Time) in public constructors.
> # Expose properties as protected.
> We should introduce the Internal Accessor / Factory Pattern (using package-private scopes and `@InterfaceAudience.Private` helper classes) to cleanly encapsulate these. 
> Subsequently, we will deprecate the leaked public constructors/methods to ensure we can remove them in 5.0.
> related discussion:
> https://lists.apache.org/thread/1kmyqody36dhnzj5ph858zsfpl4qhm7l
> https://github.com/apache/kafka/pull/21337#discussion_r3574009798



--
This message was sent by Atlassian Jira
(v8.20.10#820010)