Hibernate.java

public class Hibernate {

    public static void main(String[] args) throws Exception {
        // 次の状態を起動して、終わったらその次の状態を保存
        save(restore().call());
    }

    @MakeCallable
    static Callable<?> start() {
        System.out.println("最初");
        return HibernateDefer.next();
    }

    @MakeCallable
    static Callable<?> next() {
        System.out.println("次");
        return HibernateDefer.loop();
    }

    @MakeCallable
    static Callable<?> loop() {
        System.out.println("繰り返し");
        return HibernateDefer.next();
    }

    private static File file = new File("hibernate.bin");

    private static Callable<?> restore() {
        try {
            // ファイルから次の状態を復元
            FileInputStream in = new FileInputStream(file);
            try {
                ObjectInputStream ois = new ObjectInputStream(in);
                return (Callable<?>) ois.readObject();
            }
            finally {
                in.close();
            }
        }
        catch (IOException e) {
            // 読み出すのに失敗したらstart()から
            return HibernateDefer.start();
        }
        catch (Exception e) {
            throw new AssertionError(e);
        }
    }

    private static void save(Object object) throws IOException {
        FileOutputStream out = new FileOutputStream(file);
        try {
            // 次の状態を書き出す
            ObjectOutputStream oos = new ObjectOutputStream(out);
            oos.writeObject(object);
            oos.close();
        }
        finally {
            out.close();
        }
    }
}