java - 如何将一个列表中所做的更改反射(reflect)到另一个列表中？

Question

本质上，我想做的是有一个支持列表，它可以获取从其他“子列表”反射(reflect)到它的所有更改。更详细地说，这就是我正在尝试做的事情:

public abstract class User
{

    protected List<UserHandler> defaultHandlers
}

public class Customer extends User
{

    // All changes made to this list should the one from the parent class
    private List<CustomerHandler> userHandlers
}

public class Admin extends User
{

    // Similarily with this one
    private List<AdminHandler> adminHandlers
}

public interface UserHandler
public interface CustomerHandler extends UserHandler
public interface AdminHandler extends UserHandler

这样的功能可能吗？

Answer 1

显而易见的答案是只使用 defaultHandlers在Customer和Admin ，因为它已经设置为 protected .

但是，如果您正在寻找 defaultHandlers 的子列表这将修改 defaultHandlers ，您可以使用List#subList ;来自其documentation :

List<E> subList(int fromIndex, int toIndex)

Returns a view of the portion of this list between the specified fromIndex, inclusive, and toIndex, exclusive. (If fromIndex and toIndex are equal, the returned list is empty.) The returned list is backed by this list, so non-structural changes in the returned list are reflected in this list, and vice-versa. The returned list supports all of the optional list operations supported by this list.

请记住，如果您的程序是多线程的，则需要处理同步。