使用泛型参数扩展类

Question

I need to derive from the following class:

public abstract class MyTool<VIEW extends MyView>
  implements LookupListener, MouseListener, MouseMotionListener, KeyListener {}

The following does not work:

public abstract class MySubTool<VIEW> extends MyTool<VIEW> {}

Thanks !

Answer 1

MySubTool中的编译器无法知道MySubTool中的VIEW是MyView的子类，您必须再次指定它：

public abstract class MySubTool<VIEW extends MyView> extends MyTool<VIEW> {}

Answer 2

这应该：

public abstract class MySubTool<VIEW extends MyView> extends MyTool<VIEW> {}