来自适配器的访问片段

// 旧系统接口
interface OldSystem {
    void oldMethod();
}

// 新系统接口
interface NewSystem {
    void newMethod();
}

// 旧系统实现类
class OldSystemImpl implements OldSystem {
    @Override
    public void oldMethod() {
        System.out.println("Old system method called");
    }
}

// 适配器类
class SystemAdapter implements NewSystem {
    private OldSystem oldSystem;

    public SystemAdapter(OldSystem oldSystem) {
        this.oldSystem = oldSystem;
    }

    @Override
    public void newMethod() {
        oldSystem.oldMethod();
    }
}

// 客户端代码
public class Client {
    public static void main(String[] args) {
        OldSystem oldSystem = new OldSystemImpl();
        NewSystem newSystem = new SystemAdapter(oldSystem);
        newSystem.newMethod(); // 输出: Old system method called
    }
}