Untitled

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class PointTestBeale2
{
	public static void main(String[] args)
	{
		GUI window = new GUI();
		window.setVisible(true);
	}

	static class GUI extends JFrame
	{
		public GUI() {
			JFrame frame = new JFrame();
			JPanel content = new JPanel(new GridLayout(0,1));

			content.add(new JLabel("<html>Enter the X, Y coordinates of Line 1 and Line 2 <br>to calculate lengths and intersect points.</html>");

			JPanel linespanel = new JPanel(new GridLayout(1,2));

			line1.add(new JLabel("Line 1");
			line1.add(new JLabel("Line 2");

			content.add(linespanel);


			setContentPane(content);
			pack();

			setTitle("PointTestBeale");
			setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
			setLocationRelativeTo(null);
		}
	}

	class Calculate implements ActionListener
	{
		public void actionPerformed(ActionEvent submit)
		{

			double $d1, $d2;

			try
			{
				// Checking that input was type double
				Point line1p1 = new Point();
				Point line1p2 = new Point();
				Point line2p1 = new Point();
				Point line2p1 = new Point();

				line1p1.set(Double.parseDouble(jtf1X1.getText()),Double.parseDouble(jtf1Y1.getText()));
				line1p2.set(Double.parseDouble(jtf1X2.getText()),Double.parseDouble(jtf1Y2.getText()));
				line2p1.set(Double.parseDouble(jtf2X1.getText()),Double.parseDouble(jtf2Y1.getText()));
				line2p2.set(Double.parseDouble(jtf2X2.getText()),Double.parseDouble(jtf2Y2.getText()));

				// if the code gets to here, it was recognizable as a double
				d1 = getLength(line1p1.getX, line1p1.getY, line1p2.getX, line1p2.getY);
				d2 = getLength(line2p1.getX, line2p1.getY, line2p2.getX, line2p2.getY);
				Point.getIntersect(line1p1.getX, line1p1.getY, line1p2.getX, line1p2.getY, line2p1.getX, line2p1.getY, line2p2.getX, line2p2.getY);

				if (d1 == 0 || d2 == 0)
				{
					JOptionPane.showMessageDialog(null, "Your coordinates suggest a line of zero length. Please recheck.");
				}
				else
				{
					JOptionPane.showMessageDialog(null, Point.toString(d1, d2);
			}
			catch
			{
				JOptionPane.showMessageDialog(null, "You input improper values. Please try again.");
			}
		}

		public double getLength(double x1, double y1, double x2, double y2)
		{
			return Math.sqrt((Math.pow(x1 - x2, 2)) + (Math.pow(y1 - y2, 2)));
		}

		public void getIntersect(double l1x1, double l1y1, double l1x2, double l1y2, double l2x1, double l2y1, double l2x2, double l2y2)
		{
			double a1, a2, b1, b2, c1, c2, xint, yint;
			a1 = l1y2 - l1y1;
			b1 = l1x1 - l1x2;
			c1 = (l1y1 * l1x2) - (l1y2 * l1x1);

			a2 = l2y2 - l2y1;
			b2 = l2x1 - l2x2;
			c2 = (l2y1 * l2x2) - (l2y2 * l2x1);

			Point intersect = new Point();

			if (((a1 * b2) - (a2 * b1)) == 0)
			{
				intersect.set(null, null);
			}
			else
			{
				intersect.setX = ((b1 * c2) - (b2 * c1)) / ((a1 * b2) - (a2 * b1));
				intersect.setY = ((c1 * a2) - (c2 * a1)) / ((a1 * b2) - (a2 * b1));
			}
		}

	}
}