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Building & Running Your Codemod

There are 2 steps for turning our codemod type into a runnable codemod artifact:

  • Creating the CLI entry point code
  • Configuring our build tool to add that entry point to the manifest

Create the CLI Entry Point​

Codemodder is a library for building codemods. We need to write a small piece of code to enable our codemods to be invoked using a CLI entry point. Let's create a new type, App.java:

package io.codemodder.sample;

import io.codemodder.Runner;

public final class App {
  public static void main(String[] args) {
    Runner.run(
      List.of(ReadLinesCodemod.class), // the codemods to run
      args // the arguments
    );  
  }
}

The Runner type will handle supporting all the supported command line arguments, so you don't have to worry about any of that -- just point your Main-Class in your packaged MANIFEST.MF to MyCodeRunner, usually done with some code like this:

description = ""
val main = "io.codemodder.sample.App"
application {
    mainClass.set(main)
}

Running​

It doesn't really matter if you created a Gradle distribution zip, or a fatjar with Maven -- your project has some packaged up artifact. We can now invoke it with the standard CLI parameters and watch it work!

$ cd build/distributions/
$ unzip app.zip
$ app/bin/app /my-project-that-needs-updating