Kotlinと図で学んでみるデザインパターン -6章 Prototypeパターン-

Prototypeパターン

prototype == 原型／模範

abstract class Product : Cloneable {
    abstract fun use(s: String)
    fun createClone(): Product {
        var p: Product? = null
        try {
            p = clone() as Product
        } catch (e: CloneNotSupportedException) {
            e.printStackTrace()
        }
        return requireNotNull(p, { "product must not be null" })
    }
}

class Manager {
    private val showCase = hashMapOf<String, Product>()

    fun register(name: String, product: Product) {
        showCase[name] = product
    }

    fun create(photoName: String): Product {
        val p = showCase[photoName] as Product
        return p.createClone()
    }
}

class MessageBox(private var decoChar: String) : Product() {
    override fun use(s: String) {
        val length = s.toByteArray().size
        repeat(length + 3) {
            print(decoChar)
        }
        println("")
        println("""$decoChar $s $decoChar""")
        repeat(length + 3) {
            print(decoChar)
        }
        println("")
    }
}

class UnderLinePen(private var ulchar: String) : Product() {
    override fun use(s: String) {
        val length = s.toByteArray().size
        println("¥\"" + s + "¥\"")
        print(" ")
        repeat(length - 1) {
            print(ulchar)
        }
        println("")
    }
}

fun main() {
    val manager = Manager()
    val upen = UnderLinePen("~")
    val mbox = MessageBox("*")
    val sbox = MessageBox("/")

    manager.run {
        register("strong message", upen)
        register("warning box", mbox)
        register("slash box", sbox)
        create("strong message").use("Hello World")
        create("warning box").use("Hello World")
        create("slash box").use("Hello World")
    }
}

MEMO

データクラス - Kotlin Programming Language コピー