AsyncAPI Template for Java

[JEFFLUFC]

Our code for this proposal can be seen here

Background

We are a team of graduate developers from IBM working on an onboarding project. Our work has been to create an AsyncAPI Java Template. Our template allows a user to take an AsyncAPI document and use the AsyncAPI Generator to create Java producer/consumer code.
It currently supports AsyncAPI documents that describe:

• IBM MQ queues/topics
• Apache Kafka topics

The template is structured to make it easy to add support for additional protocols in future.
Our goal is to provide an alternative to the current Java Spring template for AsyncAPI users who aren't using the Spring framework and would prefer to generate "vanilla" Java code.

Key Files

This non-exhaustive list shows the key files in our work with brief descriptions of what they contain.

Generator Code

Path	Description
template/index.js	Entry point for the application
components/Common.js	Common/helper functions used across the generator
utils/*	Contains all filters
components/*	Contains reusable components

Generated Code

Note: Files in the output directory are created by the AsyncAPI Generator.

Path	Description
output/env.json	Used for setting environmental variables such as username and password
output/com/ibm/mq/samples/jms/PubSubBase.java	The base used for generated publishers and subscribers

Video Demo

Please click here for a video of our code in action.

Testing

Our project utilises both unit and integration testing. Our testing is accomplished using the JavaScript JEST testing framework, this follows the standard laid out in other templates. Unit testing covers almost all React components, and all string manipulation helper functions. Integration tests cover assertions at a more abstract level, namely checking the presence of files that should be generated dynamically for a given yaml definition.

An example unit test:

An example integration test:

Testing output:

Readme and Tutorial

With our contribution, we provide a README which builds on the template-for-generator-templates README, adding information specific to our template. This includes information on additional parameters that may be added to the ag command such as package which allows a user to specify the Java package that the generated code will be stored in.

We also provide a Tutorial (./template/tutorial.md) that allows a user to follow step-by-step instructions to go from having only an IBM MQ instance, to having a JMS publisher/subscriber working with a topic on their IBM MQ instance.

Future Progression of the Project

Once our work is contributed to AsyncAPI our intention, as a team, is to continue to maintain and promote further development of this template under AsyncAPI.
We would also be very happy to see contributions for supporting other AsyncAPI protocols, and have plans to add support for MQTT next.
We also want the template to make more use of the ibmmq AsyncAPI binding, such as support for queues. Some of our other thoughts on works we would like to complete include:

• Improve the mapping from channels to messages
• Add support for more JMS Types alongside JMS Text
• Add support for TLS connections
• Provide capabilities for the generated consumers to extend the Java Event Listener system if preferred by the user

Authors

• Tom Jefferson: https://github.com/JEFFLUFC
• Lewis Relph: https://github.com/lewis-relph
• Dan Raper: https://github.com/dan-r
• Kieran Murphy: https://github.com/KieranM1999
• Akshaya Gurlhosur: https://github.com/AGurlhosur
• Dale Lane: https://github.com/dalelane