java

[pardhasaradhy]

How can I create an instance of an inner class?

[Phill]

Hi
This is one way:

public class Outer {
public static void main(String[] args){
new outer();
}
public outer(){
Inner in = new Inner();//create instance and "in" is a reference to this instance
}
class Inner { //start Inner class
}//end class Inner
}//end class Outer




another common way is in the parameter of
a constructor calling another class.
For example if you create a JTable and
you want to do specific things with it
that arent standard, you have to make a
"TableModel" so you can do this by making
an inner class extending AbstractTableModel.
Then to make an instance of this Model you
can simply go:

JTable jt = new JTable(new MyModel());

These examples have both been calling
"no-args" constructors. If the inner class
has a constructor with arguments you may
have to call it instead as there may
not be a no-args constructor ie:
If the inner class has a constructor
asking for a Vector you would do
somthing like this:

Vector v = new Vector();
v.add("astring");
v.add("anotherstring");
then after adding these Objects to the
Vector you can send it to MyModel:

JTable jt = new JTable(new MyModel(v));

This creates an instance and sends info
with it.
If you want to refer to the instance later,
then the first way is best as you had a
reference variable pointing to the instance.
ie:
Inner in = new Inner();
Then to call a method in the inner class:
in.amethod();

You could have a lesson that lasted
for a week on this topic.
Hope this has helped.
Phill.