satishd commented on a change in pull request #10848:
URL: https://github.com/apache/kafka/pull/10848#discussion_r648768897
##########
File path:
storage/api/src/main/java/org/apache/kafka/server/log/remote/storage/LogSegmentData.java
##########
@@ -33,31 +34,32 @@
private final Path logSegment;
private final Path offsetIndex;
private final Path timeIndex;
- private final Path txnIndex;
+ private final Optional<Path> transactionIndex;
private final Path producerSnapshotIndex;
private final ByteBuffer leaderEpochIndex;
/**
* Creates a LogSegmentData instance with data and indexes.
- * @param logSegment actual log segment file
+ *
+ * @param logSegment actual log segment file
* @param offsetIndex offset index file
* @param timeIndex time index file
- * @param txnIndex transaction index file
+ * @param transactionIndex transaction index file, which can be null
* @param producerSnapshotIndex producer snapshot until this segment
* @param leaderEpochIndex leader-epoch-index until this segment
*/
public LogSegmentData(Path logSegment,
Path offsetIndex,
Path timeIndex,
- Path txnIndex,
+ Path transactionIndex,
Review comment:
Passing `Optional` as arguments is not considered as a good practice. We
still need to do null check for that Optional instance.
[SO answer from Brian
Goetz](https://stackoverflow.com/questions/26327957/should-java-8-getters-return-optional-type/26328555#26328555)
mentioned the right usage of `Optional`. I have also updated PR not to use it
as a field.
```
You should almost never use it as a field of something or a method parameter.
```
[Javadoc of Optional
](https://docs.oracle.com/javase/10/docs/api/java/util/Optional.html)suggests
returning as an argument mentioned below.
```
API Note:
Optional is primarily intended for use as a method return type where there
is a clear need to represent "no result," and where using null is likely to
cause errors. A variable whose type is Optional should never itself be null; it
should always point to an Optional instance.
```
Having said that, I do not have strong opinions on the above. I am fine with
the conventions that we are following in this project if we have any on
`Optional` usage.
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