Auto-shift of focus between JTextFields

Question

Greetings.
I have an array of 50 JTextFields which I restricted to a four-character entry limit. The limit works just fine, but I would like the focus to shift to the next JTextField when the limit is reached. Currently, I'm watching for the limit via an extended PlainDocument called CharLimitDocument. (*code included below) I know that Java offers the function FocusManager.focusNextComponent(Component aComp), but I'm not sure how to retrieve the current component. Can anyone help?
Thanks in advance,
Liz
*CharLimitDocument Code
import javax.swing.text.*;
import java.awt.*;
//This class overloads the Document so that a JTextField can be designed to accept only a specific number of characters.
class CharLimitDocument extends PlainDocument
private int limit;
public CharLimitDocument(int limit)
{  this.limit = limit;  }
public void insertString(int offs, String str, AttributeSet a) throws BadLocationException
if((str.length() + getLength()) <= limit)
{     super.insertString(offs, str, a);     }
else
{     Toolkit.getDefaultToolkit().beep();     }
}//end class CharLimitDocument

Answer 1

Maybe you were talking about this function in javax.swing.JComponent?
hasFocus() (returns boolean)
You could test each component to see if it hasFocus() and then you'd be able to retrieve the 'current' component (pseudo code below). Even though you have fifty fields, this still woudn't be memory/processor intensive.
Hope that helps,
H
int compindex=0;
while((compindex)<=(getComponentCount()))
     if(getComponent(compindex).hasFocus()==true)
     {this is the current component... do whatever;}
     else
     {compindex++;}
}