Kontainer

A simple DI container written in Kotlin available in maven central repository.

Why I implemented Kontainer myself?

I wanted to understand how DI containers work under the hood. I also wanted to understand how to implement a simple DI container in Kotlin.

Features

• Bean registration
• Dependency resolution
• Resolving beans by name and type
• Circular dependency detection

Building

• gradle 8.5+
• jvm 21+

Setup

Add the plugin to your build.gradle.kts file.

plugins {
    implementation("io.github.aryumka:kontainer:0.0.1")
    implementation(kotlin("reflect"))
}

Usage

class HelloDao {
    fun save(message: String) {
        println("Saving message: $message")
    }
}

class HelloService(dao: HelloDao) {
    fun sayHello() {
        dao.save("Hello, World!")
    }
}

// register a service
fun main() {
    val kontainer = Kontainer()
    //register beans 
    kontainer.register(HelloService::class)
    kontainer.register(HelloDao::class)
    
    // start the kontainer
    kontainer.start()
    
    // resolve an instance
    val helloService = kontainer.getBean<HelloService>("HelloService")
    helloService.sayHello() // prints "Saving message: Hello, World!"
}

**Note: This is inspired by DI containers such as Spring and Koin and is created for educational purposes. It may not cover all edge cases and optimizations present in production-ready libraries.

License

MIT