Refactor: Improve readability, maintainability, and reusability

[saikumarmamidala]

This pull request includes multiple refactoring changes to enhance code quality:

Extract sequence logic into getNextSequence:

Improves readability by isolating sequence calculation logic into a dedicated method.
Rename getNextSequence to calculateNextSequence:

Provides a more descriptive name for the method, reflecting its purpose of performing calculations rather than simple retrieval.
Decompose onEvent switch-case into separate methods:

Enhances clarity and modularity by breaking down the switch-case logic into smaller, focused methods.
Pull down variable to improve encapsulation and readability:

Moves a variable to the appropriate scope to better align with its usage and improve encapsulation.
Replace magic literal with named constant RUNNING:

Enhances maintainability by replacing the true literal with a descriptive constant, improving code clarity.
Move common fields to AbstractQueueProcessor superclass:

Promotes reusability and maintainability by centralizing shared fields in the superclass, simplifying subclass implementations.
These changes collectively improve the code's modularity, readability, and scalability while adhering to clean code principles.

[SamBarker]

Personally I don't think the refactoring add any meaningful value. The methods extracted don't hide much in the way of complexity or aid in understanding in the calling code.

[jonaskahn]

This line of code looks so interested to me. It takes me back to 2014 when I saw my friend create a constant ZERO = 0. So, in my point of view, we can keep this running = true following KISS