These instructions are for using the base hooks library by itself. Under most circumstances, it is advised to use the Kotlin compiler plugin with the DSL to limit the code overhead. However, if your project is Java-only or doesn't easily support Kotlin compiler plugins, it is still possible to utilize the hooks library.


Add dependency to your build.gradle(.kts):


Creating a hook

Each type of hook is exposed as an abstract class that can be subclassed to create a hook. Generally, the only additional functionality required for a hook is a public, typed call and tap method. These methods will effectively serve as the public API for your hook. Additionally, each of the base classes require a type parameter that represents the function signature for the tap method.

For example, consider a basic synchronous hook that doesn't take any parameters. This essentially could represent a simple eventing pub-sub model.

class SimpleHook : SyncHook<(HookContext) -> Unit>() {
    fun call() = super.call { f, context -> f(context) }

Note here that the type parameter for SyncHook requires HookContext as the first parameter even though this use case doesn't merit a parameter. This is the case for all hooks, regardless of the hooks' arity.

SimpleHook can then be used directly to tap and call:

fun main() {
    val hook = SimpleHook()
    hook.tap("logging") { context ->
        println("my hook was called")

You can get the full code here.

We should expect the tapped function to be executed once the hook is called, which would print the following:

my hook was called

API Documentation: