Runtime polymorphism in Kotlin

问题

Is there any elegant way to apply polymorphism in this case? The parser provides the following classes at runtime:

class io.swagger.v3.oas.models.media.Schema //is parent of the rest :

class io.swagger.v3.oas.models.media.ComposedSchema
class io.swagger.v3.oas.models.media.ArraySchema
class io.swagger.v3.oas.models.media.StringSchema
class io.swagger.v3.oas.models.media.ObjectSchema

I'd like to have function for each class with the same name and simple, short method which will cast and call necessary function at runtime. Which is actually happening, but I hope there is more brief solution, without necessity of making this kind of duplicates:

fun main() {

    val parser = OpenAPIV3Parser()
    val asList = listOf(pathYaml3, pathYml2)
    val map = asList.map(parser::read)
            .flatMap { it.components.schemas.values }
            .forEach(::parseRawSchema)
}


fun parseRawSchema(schema: Schema<Any>) {

    if (schema is ComposedSchema) {
        parseSchema(schema)
    }
    if (schema is StringSchema) {
        parseSchema(schema)
    }
...
}

fun parseSchema(schema: ComposedSchema) {
    println("Compose-schema")
}

fun parseSchema(schema: StringSchema) {
    println("Sting-schema")
}

...

回答1:

Try use extension. For example:

fun ComposedSchema.parseSchema() {
    println("Compose-schema")
}

fun StringSchema.parseSchema() {
    println("Sting-schema")
}

And than:

fun parseRawSchema(schema: Schema<Any>) {
    schema.parseSchema()
}

来源：https://stackoverflow.com/questions/57228391/runtime-polymorphism-in-kotlin