Javaの本を見ながらKotlinでThreadでの排他制御の練習をしていたやつ。

Main.kt

package com.rhizome.KotlinThreadChallenge

import kotlin.concurrent.thread
import java.util.concurrent.locks.Lock
import java.util.concurrent.locks.ReentrantLock
import kotlin.concurrent.withLock


fun main(args: Array<String>) {
    val bottle = Bottle()
    val yield = {
        while (bottle.drink(200)) {
            println(Thread.currentThread().getName() + " did drink water")
            Thread.sleep(200)
        }
    }

    val yamada = thread(name="yamada", block=yield)
    val tanaka = thread(name="tanaka", block=yield)
    yamada.join()
    tanaka.join()
    println("water: " + bottle.water)
}

class Bottle {
    var water = 1000

    class object {
        val lock = ReentrantLock()
    }

    private fun contains(amount : Int) : Boolean = amount <= water

    public fun drink(amount : Int) : Boolean {
        return lock.withLock {
            if (contains(amount)) {
                println("before water: " + water)
                water -= amount
                println("after water: " + water)
                true
            } else {
                false
            }
        }
    }
}