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Possible Duplicate:
Why is super.super.method(); not allowed in Java?

Let's assume I have 3 classes A, B and C, each one extending the previous one.

How do I call the code in A.myMethod() from C.myMethod() if B also implements myMethod?

class A
{
  public void myMethod()
  {
    // some stuff for A
  }
}

class B extends A
{
  public void myMethod()
  {
    // some stuff for B
    //and than calling A stuff
    super.myMethod();
  }
}

class C extends B
{
  public void myMethod()
  {
    // some stuff for C
    // i don't need stuff from b, but i need call stuff from A
    // something like: super.super.myMethod(); ?? how to call A.myMethod(); ??
  }
}
Community
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Arkaha
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3 Answers3

20

You can't. This is deliberate.

Class B provides an interface (as in the concept, not the Java keyword) to subclasses. It has elected not to give direct access to the functionality of A.myMethod. If you require B to provide that functionality, then use a different method for it (different name, make it protected). However, it is probably better to "prefer composition over inheritance".

Tom Hawtin - tackline
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  • Arkaha, see my answer to your question. It is syntactically possible to call a method defined by a superclass that it is not your immediate ancestor (your *super*). But you need to have a valid reason for doing so. – luis.espinal Apr 06 '10 at 12:05
2

You can't, and you shouldn't.

This is a sign of bad design. Either rename a method or include the required common functionality in another method or an utility class.

Bozho
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    Reflection *also* doesn't provide a way to do this, the normal rules of runtime polymorphism will **still apply**. You can't even implement `super.myMethod()` using reflection, let alone the theoretical `super.super.myMethod()`. – Joachim Sauer Apr 06 '10 at 11:33
  • Not necessarily, you need to do that when you define inner classes (for example, defining action listeners in Swing or call back classes.) Outside of such situations, yes, it is bad design, but *by itself* it is not. Java syntax supports it anyhow (see my response to Arkaha's question.) – luis.espinal Apr 06 '10 at 11:50
0

I'm not sure you can. Java makes all methods virtual by default. This means that the most simple solution will not work: Declare a variable of type A, assign your C instance to it and call myMethod will result in C.myMethod being called.

You could try to reflect type A and invoke its methods directly. It would be interesting to see what happens in this case, but I'd be surprised if the virtual dispatch wouldn't happen...

Daren Thomas
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