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Calling a Class

Posted on 2004-09-01
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Last Modified: 2013-11-23

I have 3 Classes, Class A, Class B and Class C.

Class A has makes calls to 2 methods func1() which is found in Class B and func2() found in Class C.

Class A extends Class B, so now func1() is accessable.

but How does Class A Call func2() which is in class c without, as java does not support multiple inheritance.

also i don't want multi-level inheritance, where in Class B extends Class C, that's not advisable.

how do i solve the problem?
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Question by:astonMarton
  • 4
  • 3
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  • +4
15 Comments
 
LVL 18

Expert Comment

by:armoghan
Comment Utility
instantiate the class c in Class A and call the method
0
 
LVL 18

Expert Comment

by:armoghan
Comment Utility
Implement interfaces
0
 
LVL 8

Expert Comment

by:thomas908
Comment Utility
class A extends B {
   new C().func2();
}

class B {
   func1() {}
}

class C {
   func2() {}
}
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LVL 6

Expert Comment

by:expertmb
Comment Utility
have an object of Class c in your Class A.
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LVL 8

Expert Comment

by:thomas908
Comment Utility
or
class A extends B {
  C c = new C();
   c.func2();
}
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LVL 12

Expert Comment

by:Giant2
Comment Utility
abstract Class D
func2 //here the body of the method

Class B extends D
func1 //here the body of the method

Class C extends D

Class A extends B
//here you can use both func1 and func2

Hope this help you.
Bye, Giant.
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Expert Comment

by:expertmb
Comment Utility
>>where in Class B extends Class C, that's not advisable
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LVL 92

Expert Comment

by:objects
Comment Utility
> How does Class A Call func2() which is in class c without, as java does not support multiple inheritance.

It can't, without having an instance of class C.
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LVL 12

Expert Comment

by:Giant2
Comment Utility
expertmb,

I told:
Class B extends D
and not: Class B extends Class C
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LVL 6

Expert Comment

by:expertmb
Comment Utility
giant2,

>>and not: Class B extends Class C
i guess he dont want to extend B from anyother class.
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LVL 12

Expert Comment

by:Giant2
Comment Utility
expertmb,

>>>and not: Class B extends Class C
>i guess he dont want to extend B from anyother class.

following what astonMarton told in the request, the only restriction is not on anyother, but only on C.
So, astonMarton must say what is the correct interpretation (I believe).

;-)
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LVL 3

Expert Comment

by:RuadRauFlessa
Comment Utility
If your solution prohibits it try looking at static methods. It allows you to call the method without having an instance of the class. However you will only be able to read and or write static variables within the class which the static method resides.

public class A {
  public void M1 () {
    //now call the methods directly through the class name rather than an instance of B or C
    //however if you have an instance of B or C you can also call it from the instance.
    B.M2 ();
    C.M3 ();
  }
}

public class B {
  private int count; // you cannot address this in M2
  private static int count2; //you can address this in M2

  public static void M2 () {
    //do whatever method needs to do
  }
}

public class C {
  private int count; // you cannot address this in M3
  private static int count2; //you can address this in M3

  public static void M3 () {
    //do whatever method needs to do
  }
}

Is there a specific reason why you need to extend from Class B???
0
 
LVL 6

Accepted Solution

by:
valipotor earned 125 total points
Comment Utility
use a inner class that extends C
in the inner class you can calll any methods from B and C
then create a wrapper method for the methods of the inner class

public class A extends B
{
   class innerA exends C
   {
      public void execute()
     {
        func1();
        func2();
     }
   }
   public void execute()
   {
    innerA a=new innerA();
    innerA.execute();
   }
}

valipotor
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LVL 6

Expert Comment

by:valipotor
Comment Utility
my mistake ;)

  public void execute()
   {
    innerA a=new innerA();
    a.execute();
   }
0
 
LVL 12

Expert Comment

by:Giant2
Comment Utility
???
0

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