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Kotlin, a type safe CommandHandler repository

Elegant Elephant answered on January 11, 2023 Popularity 1/10 Helpfulness 1/10

answer Kotlin, a type safe CommandHandler repository

Kotlin, a type safe CommandHandler repository

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class CommandHandlerRegistry(
    handlers: List<CommandHandler<out Command, *>>,
) {
    private val handlersMap: Map<Class<out Command>, CommandHandler<Command, *>>

    init {
        handlersMap = handlers.map {
            @Suppress("UNCHECKED_CAST")
            it as CommandHandler<Command, *>
        }.associateBy { it.commandClass() }
    }

    fun get(authCommand: Class<out Command>): CommandHandler<Command, *> = handlersMap[authCommand]!!
    suspend inline fun <reified R> handle(cmd: Command): R = get(cmd::class.java).handle(cmd) as R

}

// tests:
internal class CommandHandlerRegistryTest : StringSpec({
    val tested = CommandHandlerRegistry(buildList { add(TestCommandHandler()) })

    beforeTest {
        clearAllMocks()
    }

    "Should retrieve registered command handler" {
        shouldNotThrow<ClassCastException> {
            val result = tested.handle<UUID>(TestCommand())
            result shouldBe UUID.fromString(uuid)
        }
    }

    "Should fail if there is no commandHandler registered" {
        shouldThrow<NullPointerException> {
            tested.get(UnknownCommand::class.java)
        }
    }
})

interface UnknownCommand : Command
class TestCommand : Command

class TestCommandHandler : CommandHandler<TestCommand, UUID> {
    override suspend fun handle(command: TestCommand): UUID {
        return UUID.fromString(uuid)
    }

    override fun commandClass() = TestCommand::class.java
}

Popularity 1/10 Helpfulness 1/10 Language java

Source: Grepper

Tags: java repository

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Contributed on Jan 11 2023

Elegant Elephant

0 Answers Avg Quality 2/10

Kotlin, a type safe CommandHandler repository

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