Java講義 サンプル (すれっど?)

BadBank.java

public class BadBank {
    // 預金残高
    private int value = 0;

    // 預け入れ・引き出し
    public void addMoney(int money) {
        // 現在残高を保存
        int currentValue = value;
        // 状況表示
        System.out.println(Thread.currentThread() + " がaddMoneyに入りました");
        // 現在残高を変更
        value += money;
        // 矛盾がないかどうかチェック
        if (currentValue + money != value) {
            System.out.println(Thread.currentThread() + " で矛盾が発生！");
            System.exit(-1);
        }
        // 状況表示
        System.out.println(Thread.currentThread() + " がaddMoneyから出ました");
    }
}

BadBankTest.java

public class BadBankTest {
    public static void main(String...args) {
        BadBank bank = new BadBank();
        new Tester(bank).start();
        new Tester(bank).start();
    }
}

class Tester extends Thread {
    BadBank bank;

    public Tester(BadBank bank) {
        this.bank = bank;
    }

    @Override
    public void run() {
        while (true) {
            // 100円預け入れ
            bank.addMoney(100);
            // 100円引き出し
            bank.addMoney(-100);
        }
    }
}

ParallelA.java

public class ParallelA {
    public static void main(String...args) {
        ParallelASub sub = new ParallelASub();
        sub.start();

        for (int a = 0; a < 10000; a++) {
            System.out.println("main: " + a);
        }
    }
}

class ParallelASub extends Thread {
    @Override
    public void run() {
        for (int a = 0; a < 10000; a++) {
            System.out.println("-sub: " + a);
        }
    }
}

ParallelB.java

public class ParallelB {
    public static void main(String...args) {
        ParallelBSub sub = new ParallelBSub();
        Thread t = new Thread(sub);
        t.start();

        for (int b = 0; b < 1000; b++) {
            System.out.println("main: " + b);
        }
    }
}

class ParallelBSub implements Runnable {
    @Override
    public void run() {
        for (int b = 0; b < 1000; b++) {
            System.out.println("+sub: " + b);
        }
    }
}

ParallelC.java

public class ParallelC {
    public static void main(String...args) {

        new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int c = 0; c < 1000; c++) {
                        System.out.println("anon: " + c);
                    }
                }
        }).start();

        for (int c = 0; c < 1000; c++) {
            System.out.println("main: " + c);
        }
    }
}