inner classes

[ashok khetan]

If a non-static inner class has a member variable that has exactly same name as of its enclosing class then how can we access the member variable of the enclosing class in a method of inner-class?
If we write this.x or simply x then it displays the x of inner class both the times.

[Gaja Venkat]

Hi:
If the enclosing class' member variable, say x, is static then it can be referred to in the inner class' method by enclosingclassname.x
If the enclosing class' member variable x is not static, then guess, its instance must be used to refer to x.
In the following code, both x and y appear in both Outer & Inner. But in Outer, y is static and x is not static. So in inner class, o.x and Outer.y are used to refer to x and y of the Outer class respectively. The variable z appears in Outer only, so it can be referred to as just z in inner class' method.

public class Outer{
    int x=10;
    static int y=10;
    int z=10;
    public static void main(String args[]){
        Outer.Inner i= new Outer().new Inner();
        i.display();
    }
    class Inner{
        int x=20;
        int y=20;
        public void display(){
            Outer o= new Outer();
            System.out.println("x "+x);
            System.out.println("this.x "+this.x);
            System.out.println("o.x "+o.x);
            System.out.println("y "+y);
            System.out.println("Outer.y "+Outer.y);
            System.out.println("z "+z);
         }
    }
}

The output is as follows:
x 20
this.x 20
o.x 10
y 20
Outer.y 10
z 10
Hope this helps,
Gaja.

[Guy Reynolds]

The only way I know of is to pass the inner class a reference to the outer class like:
<code>
class OuterClass
{
class InnerClass
{
void method()
{
System.out.println( outer.memberVariable );
}

String memberVariable = "Inner";

public InnerClass( OuterClass outer )
{
this.outer = outer;
}

private OuterClass outer;
}

String memberVariable = "Outer";
public static void main( String[] args )
{
OuterClass outer = new OuterClass();
outer.new InnerClass( outer ).method();

}
}
</code>
This will print out "Outer".

[Christy Smith]

The easy answer is :
enclosingClassName.this.x

[Guy Reynolds]

I guess that is easier.

[Ashik Uzzaman]

Guy, very tricky example but without explanation...
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azaman