Question

假设我有一个课程如下：

private class ComparableElement extends Element implements Comparable<ComparableElement> {

        @Override
        public int compareTo(ComparableElement o) {
            return getName().compareTo(o.getName());
        }
    }

其中Elements的定义如下：

public class Element {

    protected String name;

    protected String category;

    public Element() {
        super();
    }

    public Element(String _name, String _category) {
        super();
        this.name = _name;
        this.category = _category;
    }

    public String getName() {
        return name; 
    }
}

然后，如果我有一个Element对象，最好的做法是将该Element对象转换为ComparableElement实例吗？类似的东西：

Element e;
...
ComparableElement ce = (ComparableElement)e;

只是这不起作用......

Answer 1

您可以制作新约束器ComparableElement：

public ComparableElement (Element element )
{

     //Here you get all the data from the element and set it to this object.

}

将父类实例对象转换为子类实例对象

1 个答案: