BewareMyPower opened a new pull request, #20800: URL: https://github.com/apache/pulsar/pull/20800
### Motivation When I reviewed https://github.com/apache/pulsar/pull/20597, the unrelated changes in `PersistentTopicsBase` are hard to read. The logic could be simplified to: ```java PersistentSubscription sub = null; PersistentReplicator repl = null; if (metSomeCondition()) { repl = /* ... */; if (repl == null) { /* ... */ return; } } else { sub = /* ... */; if (repl == null) { /* ... */ return; } } final PersistentSubscription finalSub = sub; final PersistentReplicator finalRepl = repl; future.thenAccept(__ -> { if (metSomeCondition()) { repl.expireMessages(/* ... */); } else { sub.expireMessages(/* ... */); } }); ``` The code above is such a mess. It adds two final variables because the lambda can only capture final variables. The `metSomeCondition` check is performed unnecessarily twice. The original code is more hard to read because the logic in `/* ... */` takes a few lines so that the two calls of `metSomeCondition()` are not near. From the code search I see all these classes implement two `expireMessages` methods that accept an integer or a position. - PersistentMessageExpiryMonitor - PersistentSubscription - PersistentReplicator - NonPersistentSubscription The code can be simplified to introduce a new interface. ### Modifications Introduce a `MessageExpirer` interface and change the class hierarchy to: ``` // [I] is interface, [C] is class [I] MessageExpirer [I] Subscription [C] PersistentSubscription [C] NonPersistentSubscription [C] PersistentReplicator [C] PersistentMessageExpiryMonitor ``` The method invocation can be simplified much as shown in this patch. P.S. Inserting such an interface in the type hierarchy does not even break the ABI compatibility, see https://docs.oracle.com/javase/specs/jls/se7/html/jls-13.html ### Does this pull request potentially affect one of the following parts: <!-- DO NOT REMOVE THIS SECTION. CHECK THE PROPER BOX ONLY. --> *If the box was checked, please highlight the changes* - [ ] Dependencies (add or upgrade a dependency) - [x] The public API - [ ] The schema - [ ] The default values of configurations - [ ] The threading model - [ ] The binary protocol - [ ] The REST endpoints - [ ] The admin CLI options - [ ] The metrics - [ ] Anything that affects deployment ### Documentation - [ ] `doc` <!-- Your PR contains doc changes. --> - [ ] `doc-required` <!-- Your PR changes impact docs and you will update later --> - [] `doc-not-needed` <!-- Your PR changes do not impact docs --> - [ ] `doc-complete` <!-- Docs have been already added --> ### Matching PR in forked repository PR in forked repository: -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
