singhvishalkr opened a new pull request, #1125:
URL: https://github.com/apache/pulsar-site/pull/1125
### Motivation
Fixes apache/pulsar#24007.
The `TableView` documentation shows `forEach` and `forEachAndListen`
side-by-side but does not describe how a tombstone (a message with a `null`
payload) flows through either API. The reporter asked specifically whether
`forEach` sees tombstoned keys, and whether the listener registered via
`forEachAndListen` is invoked for tombstones.
The Java implementation at
`pulsar-client/src/main/java/org/apache/pulsar/client/impl/TableViewImpl.java`
is the source of truth:
```java
if (null == cur) {
data.remove(key);
} else {
data.put(key, cur);
}
for (BiConsumer<String, T> listener : listeners) {
try {
listener.accept(key, cur);
} catch (Throwable t) {
log.error().exception(t).log("Table view listener raised an
exception");
}
}
```
So the behaviour is:
* `forEach(action)` iterates only over the current map snapshot --
tombstoned keys are not surfaced.
* `forEachAndListen(action)` first runs `forEach` over the non-tombstoned
entries, then registers the action. Every subsequent update (tombstones
included) is delivered to the listener as `accept(key, null)`.
### Modifications
Added a `:::note Tombstone (null-value) messages` block under the **Register
listeners** section in:
* `docs/client-libraries-tableviews.md`
* `versioned_docs/version-4.2.x/client-libraries-tableviews.md`
* `versioned_docs/version-4.1.x/client-libraries-tableviews.md`
* `versioned_docs/version-3.3.x/client-libraries-tableviews.md`
The note names the backing behaviour and tells users to check `value ==
null` inside their listener if they need to react to deletions.
### Verifying this change
* Manual review of the added Markdown renders as the intended note block.
* No code paths changed.
### Does this pull request potentially affect one of the following parts:
- [x] Documentation
### Documentation
- [x] `doc-label-required` -- Your PR contains documentation changes.
### Matching PR in forked repository
PR in forked repository: singhvishalkr/pulsar-site#1
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