public void actionPerformed(ActionEvent event)
	{
		String entry = entryField.getText().trim();
		
		if(entry.length() > 1 && entry.charAt(entry.length()-1) == '%')
			entry = entry.substring(0,entry.length()-1);
		
		if(event.getActionCommand().equals("Update"))
		{
			if(entry.equals(""))
				JOptionPane.showMessageDialog(null,"ERROR: Invalid Entry");
			else if(Tools.isNonNegativeNumber(entry))
			{
				discountAmount = Double.parseDouble(entry);
				saveDiscount();
				displayField.setText(String.valueOf(discountAmount) + "%");
				entryField.setText("");
			}
			else
				JOptionPane.showMessageDialog(null,"ERROR: Discount Amount Must Be a Non-negative Number");
		}
		
		if(event.getActionCommand().equals("5% Discount"))
		{
			discountAmount = 5.0;
			saveDiscount();
			displayField.setText(String.valueOf(discountAmount) + "%");
		}
		
		if(event.getActionCommand().equals("10% Discount"))
		{
			discountAmount = 10.0;
			saveDiscount();
			displayField.setText(String.valueOf(discountAmount) + "%");
		}
		
		if(event.getActionCommand().equals("50% Discount"))
		{
			discountAmount = 50.0;
			saveDiscount();
			displayField.setText(String.valueOf(discountAmount) + "%");
		}
		
	}