version-processor/README.md

A simple annotation processing example

This project demonstrates a simple annotation processor that is built with Kobalt. The annotation processor allows you to generate a Version class containing a version number that is either read from a Properties file or directly defined in the annotation.

There are two modules in this project:

• The processor (processor/)
• The example using the processor (example/)

The processor project defines an annotation @Version that lets you specify a version number in two ways:

• Either provide a value for the version.
• Or you provide a fileName pointing to a Properties file. This file contains the version number either with the default key version or with your own key, which you can specify with the propertyName attribute.

For example:

@Version(fileName = "example/src/main/properties/version.properties",
    propertyName = "example.version")
public class A {
// ...

And the content of the version.properties file:

example.version=1.4

When the annotation processor is run, it generates a source file GeneratedVersion.java with a static field containing that version number.

The example project has a single class Example which is annotated with @Version and which then displays the value of the version from the GeneratedVersion generated class.

To build and run the example:

./kobaltw run