AutoMultiBind

My simple KSP processor that generates dagger modules with multibindings

Setup

repositories {
    maven { url = uri("https://oss.sonatype.org/content/repositories/releases/") }
}

dependencies {
    implementation("ru.fredboy:automultibind-annotations:1.0.4")
    ksp("ru.fredboy:automultibind-ksp:1.0.4")
}

How It Works

For usage example see sample module

Instead of manually writing:

@Module
abstract class MyInterfaceIntoSetModule {

    @Binds @IntoSet
    abstract fun bindMyImplementation1(impl: MyImplementation1): IMyInterface

    @Binds @IntoSet
    abstract fun bindMyImplementation2(impl: MyImplementation2): IMyInterface
}

You can simply annotate your implementations:

@BindMyInterfaceIntoSet
@BindMyInterfaceIntoMap(stringKey = MyImplementation1.KEY)
class MyImplementation1 @Inject constructor() : IMyInterface {

    override fun getString() = "My implementation #1"

    companion object {
        const val KEY = "MyImplementation1_Key"
    }
}

The processor scans for these annotations and generates all the necessary Dagger modules.

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Step-by-Step Usage

1. Create Your Interface

interface IMyInterface {
    fun getString(): String
}

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2. Create Binding Annotations

For example, for IntoSet bindings:

@BindsIntoSet(
    interfaceClass = IMyInterface::class,
    modulePackage = AutomultibindConfig.MODULE_PACKAGE,
    moduleName = "MyInterfaceIntoSetModule"
)
annotation class BindMyInterfaceIntoSet

For IntoMap bindings with StringKey:

@BindsIntoMapStringKey(
    interfaceClass = IMyInterface::class,
    modulePackage = AutomultibindConfig.MODULE_PACKAGE,
    moduleName = "MyInterfaceIntoMapModule"
)
annotation class BindMyInterfaceIntoMap(val stringKey: String)

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3. Annotate Your Implementations

@BindMyInterfaceIntoSet
@BindMyInterfaceIntoMap(stringKey = MyImplementation2.KEY)
class MyImplementation2 @Inject constructor() : IMyInterface {

    override fun getString() = "My implementation #2"

    companion object {
        const val KEY = "MyImplementation2_Key"
    }
}

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4. Use the Generated Modules in Your Component

The processor will generate modules like:

@Module
@Generated(value = ["ru.fredboy.automultibind.processor.BindsIntoSetSymbolProcessor"])
abstract class MyInterfaceIntoSetModule {

    @Binds @IntoSet
    abstract fun bindMyImplementation1(impl: MyImplementation1): IMyInterface

    @Binds @IntoSet
    abstract fun bindMyImplementation2(impl: MyImplementation2): IMyInterface
}

@Module
@Generated(value = ["ru.fredboy.automultibind.processor.BindsIntoMapStringKeySymbolProcessor"])
abstract class MyInterfaceIntoMapModule {

    @Binds @IntoMap @StringKey("MyImplementation1_Key")
    abstract fun bindMyImplementation1(impl: MyImplementation1): IMyInterface

    @Binds @IntoMap @StringKey("MyImplementation2_Key")
    abstract fun bindMyImplementation2(impl: MyImplementation2): IMyInterface
}

Then you just include them in your Dagger component:

@Component(
    modules = [
        MyInterfaceIntoSetModule::class,
        MyInterfaceIntoMapModule::class
    ]
)
interface MyComponent {
    fun getMyClass(): MyClass
}

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Benefits

• Zero boilerplate: Just annotate your implementation, and modules are generated.
• Type-safe: Module signatures are generated based on your actual types.
• Consistent: All modules follow the same style and conventions.
• Flexible: Works for both IntoSet and IntoMap bindings (string keys).

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