[ISSUE #7788] Refactor AllocateMachineRoomNearby

[wyyl1]

Which Issue(s) This PR Fixes

Refactor

Fixes #7788

Brief Description

1. Consistency in abstraction levels
2. Use method names instead of comments
3. Make the code more concise: inline the result returned by a successful condition into a block of code

How Did You Test This Change?

AllocateMachineRoomNearByTest ran successfully

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 95.00000% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 42.89%. Comparing base (88e6447) to head (23c5fa9).

Files	Patch %	Lines
.../consumer/rebalance/AllocateMachineRoomNearby.java	95.00%	1 Missing :warning:

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #7789      +/-   ##
=============================================
+ Coverage      42.86%   42.89%   +0.02%     
- Complexity     10348    10357       +9     
=============================================
  Files           1270     1270              
  Lines          88666    88677      +11     
  Branches       11397    11395       -2     
=============================================
+ Hits           38009    38036      +27     
+ Misses         45963    45945      -18     
- Partials        4694     4696       +2     

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[BitoAgent]

PR Run Status

• AI Based Review: Successful
• Static Analysis: Failure - Build failed prior to static code analysis using FBinfer.

PR Analysis

• Main theme: Refactoring of AllocateMachineRoomNearby for better abstraction, clarity, and efficiency.
• PR summary: This PR introduces a significant refactor of the AllocateMachineRoomNearby class, aiming to improve the code's readability, maintainability, and efficiency. Key changes include parameter validation at construction, leveraging Java's Collections utility for empty lists, and restructuring the allocation logic into more granular, understandable methods.
• Type of PR: Refactoring
• Score (0-100, higher is better): 85
• Relevant tests added: No
• Estimated effort to review (1-5, lower is better): 2 The refactor is straightforward with clear improvements in code structure and readability, though careful review is needed to ensure logic consistency and performance implications.

PR Feedback

• General suggestions: The PR successfully achieves its goal of refactoring the AllocateMachineRoomNearby class for better readability and maintainability. The changes make the code more modular, easier to understand, and potentially easier to test. However, there are opportunities to further enhance the code, particularly in terms of efficiency and scalability. It's also important to ensure that all new methods have corresponding unit tests to maintain coverage and ensure functionality correctness. Additionally, considering the potential impact of these changes on the overall system's behavior, it would be beneficial to perform more extensive testing, including integration and performance tests, to ensure that the refactor does not introduce regressions or significantly affect the system's performance.

Code feedback

file: client/src/main/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMachineRoomNearby.java

• Suggestions:

1. Consider using more specific exceptions rather than NullPointerException for null checks in checkParams method. IllegalArgumentException might be more appropriate, providing more context about the error. [important] Relevant line:In client/src/main/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMachineRoomNearby.java at line 24

+ checkParams(allocateMessageQueueStrategy, machineRoomResolver);

2. For better scalability and performance, consider parallelizing the groupMqByMachineRoom and groupConsumerByMachineRoom methods if the size of mqAll and cidAll lists is expected to be large. [medium] Relevant line:In client/src/main/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMachineRoomNearby.java at line 74

+ private Map<String, List<MessageQueue>> groupMqByMachineRoom(List<MessageQueue> mqAll) {

3. In the allocateQueues method, consider checking if mr2Mq and mr2c maps are empty before proceeding with allocation logic to avoid unnecessary processing. [medium] Relevant line:In client/src/main/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMachineRoomNearby.java at line 98

+ private List<MessageQueue> allocateQueues(String consumerGroup, String currentCID, List<String> cidAll,

4. Ensure that the new methods introduced (e.g., allocateSameRoomQueues, allocateRestQueues) are covered by unit tests to verify their behavior independently. [important] Relevant line:In client/src/main/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMachineRoomNearby.java at line 82

+ private List<MessageQueue> allocateSameRoomQueues(String consumerGroup, String currentCID, Map<String, List<MessageQueue>> mr2Mq,

5. Consider the impact of removing entries from mr2Mq map on line 125. If the method is called multiple times or expected to be reused, this could lead to unexpected behavior. [medium] Relevant line:In client/src/main/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMachineRoomNearby.java at line 125

+ List<MessageQueue> mqInThisMachineRoom = mr2Mq.remove(currentMachineRoom);

6. Review the necessity of TreeMap for mr2Mq and mr2c. If ordering is not essential for the logic, using HashMap could offer better performance. [medium] Relevant line:In client/src/main/java/org/apache/rocketmq/client/consumer/rebalance/AllocateMachineRoomNearby.java at line 74

+ Map<String/*machine room */, List<MessageQueue>> mr2Mq = new TreeMap<>();