CODEWITHSUNDEEP
kotlincasting
NeverSleeps
NeverSleeps

Reputation: 1902

Why does the casting of classes not work in kotlin?

I send such list to the function: listOf(IncomeVerificationType::class, IncomeType::class), but function returns the map only with "id". Why is is not working? What am I doing wrong?

Function:

    fun sendUpdatedEvent(model: Model, updatedFields: List<Any>): Map<String, Any> {
        val fieldToValueMap = mapOf("id" to model.identity.id)
        updatedFields.forEach {
            when (it) {
                is IncomeVerificationType -> fieldToValueMap.plus("incomeVerification" to model.incomeVerification)
                is IncomeType -> fieldToValueMap.plus("incomeTypeId" to model.incomeTypeId)
            }
        }
        return fieldToValueMap
    }

Upvotes: 0

Views: 79

Answers (1)

RobCo
RobCo

Reputation: 6495

Because IncomeType::class is not an instance of IncomeType.
The type of IncomeType::class is KClass<IncomeType>. It references the class itself, not an instance of the class.

To correctly match those class objects in a when statement you can use the regular equality checks instead of the 'is' check:

    val list = listOf(IncomeVerificationType::class, IncomeType::class)
    list.forEach {
        when (it) {
           IncomeVerificationType::class -> println("IncomeVerificationType")
           IncomeType::class -> println("IncomeType")
        }
    }

Upvotes: 2

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