TemplateMethod:kotlin

気を付けたこと

• kotlinでは複数のクラスを一つのファイルにまとめることが出来るのでまとめた
• 文字列リテラル内に”${式}”で直接変数や値を埋め込める

fun main(args: Array<String>) {
    val d1: AbstractDisplay = CharDisplay('H')
    val d2: AbstractDisplay = StringDisplay("Hello,world.")
    val d3: AbstractDisplay = StringDisplay("こんにちは")
    d1.display()
    d2.display()
    d3.display()
}
abstract class AbstractDisplay {
    abstract fun open()
    abstract fun print()
    abstract fun close()
    fun display() {
        open()
        for (i in 0 until 5) {
            print()
        }
        close()
    }
}
class CharDisplay(private val ch:Char) : AbstractDisplay() {
    override fun open() {
        print("<<")
    }

    override fun close() {
        println(">>")

    }

    override fun print() {
        print(ch)
    }

}
class StringDisplay(private val string:String):AbstractDisplay(){
    private val width:Int
    init {
        width = string.toByteArray().size
    }

    override fun open() {
        printLine()
    }

    override fun print() {
        println("|${string}|")
    }

    override fun close() {
        printLine()
    }
    private fun printLine() {

        print("+")
        for (i in 0 until width) {
            print("-")
        }
        println("+")
    }
}

元のコードは以下の本からの引用です。サンプルコードは著者さんのサイトで配布されています。リンクはAmazonアソシエイトを使用しています。

増補改訂版Java言語で学ぶデザインパターン入門

ライセンス表記

Copyright (C) 2001,2004 Hiroshi Yuki.

Java言語で学ぶデザインパターン入門 第3版

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