[KAFKA-6673] Segment and Stamped implement Comparable, but don't override equals.

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Component/s: streams
• Assignee: Asutosh Pandya
• Reporter: Koen De Groote
• Created: 16/Mar/18 22:01
• Updated: 09/May/18 17:35
• Resolved: 09/May/18 17:35

Description

The classes in question:

https://github.com/apache/kafka/blob/trunk/streams/src/main/java/org/apache/kafka/streams/state/internals/Segment.java

and

https://github.com/apache/kafka/blob/trunk/streams/src/main/java/org/apache/kafka/streams/processor/internals/Stamped.java

This came up while doing static analysis on the codebase on the trunk branch.

As described by the analysis tool built into Intellij:

Reports classes which implement java.lang.Comparable which do not override equals(). If equals() is not overridden, the equals() implementation is not consistent with the compareTo() implementation. If an object of such a class is added to a collection such as java.util.SortedSet, this collection will violate the contract of java.util.Set, which is defined in terms of equals().

 

Implementing an equals for an object is generally a best practice, especially considering this caveat, where it's not the compareTo that will be used but the equals method.