docs: align microservices-messaging README with actual Kafka-based implementation

[1wu-davy-2]

Description

The "Programmatic Example" section documented an in-memory MessageBroker class with subscribe/publish methods, an OrderService(MessageBroker) constructor and a matching console output block. None of that exists in the module.

The actual implementation uses Apache Kafka:

• There is no MessageBroker class. KafkaMessageProducer wraps a Kafka Producer, serializes each Message to JSON and publishes it to a topic.
• OrderService takes a KafkaMessageProducer in its constructor and publishes to the order-topic constant.
• App connects to localhost:9092, creates three KafkaMessageConsumers (inventory-group, payment-group, notification-group) on order-topic, and runs them in a thread pool.
• The console output block was replaced with the log statements the code actually emits (abridged; message ids are omitted because they are random UUIDs).

The "How to Run" section was left unchanged: it already describes the Docker Compose / helper-script Kafka setup correctly.

Checklist

• Only documentation change (microservices-messaging/README.md)
• Snippets and log strings verified against App.java, OrderService.java, KafkaMessageProducer.java and the three consumer services
• No remaining references to MessageBroker

Assisted by AI tools for initial analysis; all changes manually verified and tested.

[github-actions]

PR Summary

Updates the README to reflect the Kafka-based messaging implementation. Replaces the in-memory MessageBroker with Kafka-based producer/consumer concepts, shows KafkaMessageProducer, OrderService using the producer for order-topic, and App wiring KafkaMessageConsumer instances. Adjusts the console output to reflect the Kafka flow and removes references to MessageBroker.

Changes

File	Summary
microservices-messaging/README.md	Replaced in-memory MessageBroker example with Kafka-based producer/consumer code. Documented KafkaMessageProducer wrapping a Kafka Producer, OrderService using it to publish to order-topic, and App wiring three KafkaMessageConsumers for inventory-group, payment-group, and notification-group. Updated console/log outputs to reflect actual Kafka-based flow and removed references to MessageBroker.

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autogenerated by presubmit.ai

[github-actions]

✅ LGTM!

Review Summary

Commits Considered (1)

• 8df5f64: docs: align microservices-messaging README with actual Kafka-based implementation

Files Processed (1)

• microservices-messaging/README.md (3 hunks)

Actionable Comments (0)

Skipped Comments (4)

• microservices-messaging/README.md [74-87]

  best_practice: "KafkaMessageProducer snippet lacks self-contained initialization and resource management."

• microservices-messaging/README.md [93-109]

  enhancement: "Clarify Kafka-based wiring in OrderService."

• microservices-messaging/README.md [140-168]

  readability: "Document App wiring and lifecycle behavior."

• microservices-messaging/README.md [173-189]

  readability: "Document console output expectations and IDs."

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.01%. Comparing base (4cabb20) to head (8df5f64).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3625      +/-   ##
============================================
- Coverage     84.06%   84.01%   -0.05%     
+ Complexity     4353     4350       -3     
============================================
  Files          1133     1133              
  Lines         15400    15400              
  Branches        739      739              
============================================
- Hits          12946    12939       -7     
- Misses         2158     2162       +4     
- Partials        296      299       +3     

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