As changes Are done on the JtextArea show graphics,How ?

[taptaptill]

Hello Everyone and thx in advance.
So my problem is I want to draw on a JPanel something on condition on what's been inserted in the JtextArea is this correct? :
DocumentListener to check on the insert operation

    protected class MyDocumentListener  extends JPanel implements javax.swing.event.DocumentListener {
        @Override
   public void changedUpdate(javax.swing.event.DocumentEvent e) {
            // text has been altered in the textarea
            
            }
        @Override
   public void insertUpdate(javax.swing.event.DocumentEvent e) 
        {
                // text has been added to the textarea 
                      
            try { 
               //if not prompt Line
                if (!Traffic.getText(Traffic.getLineStartOffset(Traffic.getLineCount()-1),
                  Traffic.getLineEndOffset(Traffic.getLineCount()-1)-Traffic.getLineStartOffset(Traffic.getLineCount()-1)).contains(">>"))
          {//if a line after a replace has been inserted
              
              if (Traffic.getLineCount()  == (lastreplace + 2) ) 
              {
System.err.println(Traffic.getText(Traffic.getLineStartOffset(lastreplace),
                                Traffic.getLineEndOffset(lastreplace) - 
                                        Traffic.getLineStartOffset(lastreplace)));
                   PortArchitecture (Traffic.getText(Traffic.getLineStartOffset(lastreplace),
                                Traffic.getLineEndOffset(lastreplace) - 
                                        Traffic.getLineStartOffset(lastreplace)));
                      
                   lastreplace +=1;

              }
              
           
                else//last line when it's not detected by the previous condition it'll be consumed here
              {
                 System.err.println(Traffic.getText(Traffic.getLineStartOffset(lastreplace),
                                Traffic.getLineEndOffset(lastreplace) - 
                                        Traffic.getLineStartOffset(lastreplace)));
                 PortArchitecture (Traffic.getText(Traffic.getLineStartOffset(lastreplace),
                                Traffic.getLineEndOffset(lastreplace) - 
                                        Traffic.getLineStartOffset(lastreplace))); 
              }
          }
            Traffic.setCaretPosition(Traffic.getDocument().getLength());
            
            } catch (BadLocationException ex) {
                Logger.getLogger(TrafficSerialPort.class.getName()).log(Level.SEVERE, null, ex);
            }

        }
        
        @Override
   public void removeUpdate(javax.swing.event.DocumentEvent e) {
      // text has been removed from the textarea
           
   }
    }

Methode to check the condition and draw on the JPanel :

public void PortArchitecture (String line) throws BadLocationException 
{
    
  Graphics2D gfx = (Graphics2D)graphicPanel.getGraphics();
        String [] valuesId = new String [2];
        valuesId = line.split(":");
        /**switch (valuesId[0])
        {
            case "Port Number" : draw();
        }*/
        if(valuesId[0].contains("Port number"))
        {
            
         gfx.drawString("(PN)", 30, 10);
         gfx.drawString(valuesId[1],30, 140);
    }
        if(valuesId[0].contains("Port Extension"))
        {
            gfx.drawString("(EXT)", 100, 10);
            gfx.drawString(valuesId[1], 100, 140);
          //  draw(g);
    }
        if(valuesId[0].contains("Forward Extension"))
        {
            gfx.drawLine(140,80,140,110);
          //  draw(g);
    }
        if(valuesId[0].contains("ON-HOOK"))
        {
          //  draw(g);
    }
        if(valuesId[0].contains("OFF-HOOK"))
        {
           // draw(g);
    }
        if(valuesId[0].contains("Forward status"))
        {
            if(valuesId[1].contains("FORWARDED"))
            {
               // draw(g);
            }
            else
            {
               // draw(g);
            }
    }
        if(valuesId[0].contains("Dialing"))
        {
            //get dialed number
            //draw(g);
    }

}

And another thing : I have some result concerning Showing some drawings but when I minimize the application all the graphics are gone.I know I need to call the repaint() but I don't know when and how.
Help please!

[DarrylBurke]

Never use getGraphics() of a Component. Learn the correct approach to Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing)

db

[taptaptill]

really it's making me crazy!!
now I want on the event of INSERT then draw how do I do that ?!!! please help
I tried to add the paintComponent(Graphics g) methods & I did override it and still dosn't work.
I undrestand that I need to call the class containing the paintComponent like this : frame.add(new MyPanel());
well I can't do that cause I need to get the event from the DocumentListener and I can't get it outside that Class, but still the paintComponent dosn't (I think) where to draw that's why nothing shows !!