TaxGuiFile7.java

import java.awt.event.*;
import javax.swing.*;
import java.awt.GridLayout;
import java.io.FileInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Vector;

public class TaxGuiFile7 extends JFrame implements ActionListener {
 JLabel lblGrIncome;
 JTextField txtGrossIncome = new JTextField(15);
 JLabel lblDependents=new JLabel("Number of Dependents:");
 JTextField txtDependents = new JTextField(2);
 JLabel lblState = new JLabel("State: ");
 
 //Define a data model for the ComboBox chState
 Vector states = new Vector(50); 
 
 //Create a combobox to get data from the model 
 JComboBox chState = new JComboBox(states);

 JLabel lblTax = new JLabel("State Tax: ");
 JTextField txtStateTax = new JTextField(10);
 JButton bGo = new JButton("Go");
 JButton bReset = new JButton("Reset");
 
 TaxGuiFile7() {
 lblGrIncome = new JLabel("Gross Income: ");
 GridLayout gr = new GridLayout(5,2,1,1);
 setLayout(gr);

 add(lblGrIncome);
 add(txtGrossIncome);
 add(lblDependents);
 add(txtDependents);
 add(lblState);
 add(chState);
 add(lblTax);
 add(txtStateTax);
 add(bGo);
 add(bReset);

 // Populate states from a file
 populateStates();
 
 chState.setSelectedIndex(0);

 txtStateTax.setEditable(false);

 bGo.addActionListener(this);
 bReset.addActionListener(this);

 // Define, instantiate and register a WindowAdapter
 // to process windowClosing Event of this frame

	this.addWindowListener(new WindowAdapter() {
	 public void windowClosing(WindowEvent e) {
 System.out.println("Good bye!");
		 System.exit(0);
	 }});
 }

 public void actionPerformed(ActionEvent evt) {
 Object source = evt.getSource();
 if (source == bGo ){
 // The Button Go processing
 try{
 int grossInc =Integer.parseInt(txtGrossIncome.getText());
 int dependents = Integer.parseInt(txtDependents.getText());
 String state = (String)chState.getSelectedItem();

 Tax tax=new Tax(dependents,state,grossInc);
 String sTax =Double.toString(tax.calcTax());
 txtStateTax.setText(sTax);
 }catch(NumberFormatException e){
 txtStateTax.setText("Non-Numeric Data");
 }catch (Exception e){
 txtStateTax.setText(e.getMessage());
 }
 }
 else if (source == bReset ){
 // The Button Reset processing
		txtGrossIncome.setText("");
		txtDependents.setText("");
 chState.setSelectedIndex(0);
		txtStateTax.setText("");
 }
 }
 // The code below will read the file states.txt and 
 // populate the dropdown chStates
 private void populateStates(){
 
 states.add("Select State");
 
 try ( FileInputStream myFile = new FileInputStream("states.txt");
 	 InputStreamReader inputStreamReader = 
 new InputStreamReader(myFile, "UTF8");
 	 BufferedReader reader = new BufferedReader(inputStreamReader);) {
 	 
 String nextLine;
 boolean eof = false;
 while (!eof) {
 	 nextLine = reader.readLine();
 	 if (nextLine == null){
 eof = true; 
 	 } else {
 // Populate the model	
 states.add(nextLine);
 	 } 
 }
 
 }catch (IOException e){
 txtStateTax.setText("Can't read states.txt");
 }
 }

 public static void main(String args[]){
 TaxGuiFile7 taxFrame = new TaxGuiFile7();
 taxFrame.setSize(400,150);
 taxFrame.setVisible(true);
 }
}