2 columns working together to return one value

Question

I'm creating an expense reimbursement form. I have 2 columns that need to "work together." There are approx. 10 rows. The first column is a drop down list of account numbers (12 #s). The second column is a dollar amount (user entered). I need 12 "fields" (one for each acct. #) that will look at all the fields in column 1 and add up the dollar amounts in column 2 if the column 1 data matches.
Example:
Column 1 Column 2
Acct. 12345 $10.00
Acct. 67890 $5.00
Acct. 12345 $20.00
Acct. 12345 Total: $30.00
Acct. 67890 Total: $5.00
Thanks for the help!

Answer 1

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TwoOfAKind extends JFrame implements AdjustmentListener {
  JScrollBar scrollBar1, scrollBar2;
  public TwoOfAKind() {
    JPanel panel1 = new JPanel();
    panel1.setPreferredSize(new Dimension(150,600));
    JPanel panel2 = new JPanel();
    panel2.setPreferredSize(new Dimension(150,600));
    JScrollPane scroll1 = new JScrollPane(panel1);
    scrollBar1 = scroll1.getVerticalScrollBar();
    scrollBar1.addAdjustmentListener(this);
    JScrollPane scroll2 = new JScrollPane(panel2);
    scrollBar2 = scroll2.getVerticalScrollBar();
    scrollBar2.addAdjustmentListener(this);
    getContentPane().setLayout(new GridLayout(1,2));
    getContentPane().add(scroll1);
    getContentPane().add(scroll2);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(400,300);
    setLocation(400,300);
    setVisible(true);
  public void adjustmentValueChanged(AdjustmentEvent e) {
    JScrollBar scrollBar = (JScrollBar)e.getAdjustable();
    int value = scrollBar.getValue();
    if(scrollBar == scrollBar1)
      scrollBar2.setValue(value);
    if(scrollBar == scrollBar2)
      scrollBar1.setValue(value);
  public static void main(String[] args) {
    new TwoOfAKind();
}