Complex Numbers Regex Application

package ComplexRegex;
/*
 * Lu Liu
 * CSC-112 Intermediate Java Programming
 * 03/01/2016
 * lliu0001@ student.stcc.edu
 *
 * #HW8
 * Complex Numbers Regex Application:
 * 1)test client;
 * 2)generate two Complex Number a and b;
 * 3)operate Complex Number a and b;
 * 4) one of the constructors takes a String such as "3+5i", or "17.5-21.3i", or "3.1416", or "99i";
 */

import java.util.regex.*;
import javax.swing.JOptionPane;

public class ComplexRegex {

    // test client
    public static void main(String[] args) {
        final String TITLE = "ComplexNumber Demo";
        JOptionPane.showMessageDialog(null, "Running " + TITLE + "\nHave Fun!!!", TITLE,
                JOptionPane.INFORMATION_MESSAGE);

        do {
            // generate two Complex Number a and b, and test them;
            final String TITLE1 = "ComplexNumber Demo";
            String temp;

            temp = JOptionPane.showInputDialog(null, "Enter Complex Number 1: ", TITLE1,
                    JOptionPane.INFORMATION_MESSAGE);
            Complex a = new Complex(temp);

            temp = JOptionPane.showInputDialog(null, "Enter Complex Number 2: ", TITLE1,
                    JOptionPane.INFORMATION_MESSAGE);
            Complex b = new Complex(temp);

            Complex ans = null;
            String options[] = { "Add", "Subtract", "Multiply", "Divide", "Distance", "Compare", "negate", "conjugate",
                    "abs", "Quit" };
            int option = JOptionPane.showOptionDialog(null, "Choose Operation", TITLE, JOptionPane.YES_NO_CANCEL_OPTION,
                    JOptionPane.PLAIN_MESSAGE, null, options, 4);
            String output = "";
            switch (option) {
            case 0:
                ans = a.add(b);
                output = " + ";
                break;
            case 1:
                ans = a.subtract(b);
                output = " - ";
                break;
            case 2:
                ans = a.multiply(b);
                output = " * ";
                break;
            case 3:
                ans = a.divide(b);
                output = " / ";
                break;
            default:
                break;
            }
            if (option == 4) {
                JOptionPane.showMessageDialog(null, a + " and " + b + " 's diatance = " + a.distance(b), TITLE,
                        JOptionPane.PLAIN_MESSAGE);
            } else if (option == 5) {
                if (a.equals(b))
                    JOptionPane.showMessageDialog(null, a + " is equals to " + b, TITLE, JOptionPane.PLAIN_MESSAGE);
                else if (a.greaterThan(b))
                    JOptionPane.showMessageDialog(null, a + " is greater than " + b, TITLE, JOptionPane.PLAIN_MESSAGE);
                else
                    JOptionPane.showMessageDialog(null, a + " is less than " + b, TITLE, JOptionPane.PLAIN_MESSAGE);

            } else if (option == 6) {
                Complex ans1 = a.negate();
                Complex ans2 = b.negate();
                JOptionPane.showMessageDialog(null,
                        a + " 's negation is " + ans1 + "\n" + b + " 's negation is " + ans2, TITLE,
                        JOptionPane.PLAIN_MESSAGE);
            } else if (option == 7) {
                Complex ans1 = a.conjugate();
                Complex ans2 = b.conjugate();
                JOptionPane.showMessageDialog(null,
                        a + " 's conjugate is " + ans1 + "\n" + b + " 's conjugate is " + ans2, TITLE,
                        JOptionPane.PLAIN_MESSAGE);
            }

            else if (option == 8) {
                double ans1 = a.abs();
                double ans2 = b.abs();
                JOptionPane.showMessageDialog(null,
                        a + " 's distance is " + ans1 + "\n" + b + " 's distance is " + ans2, TITLE,
                        JOptionPane.PLAIN_MESSAGE);
            } else if (option > 8)
                break;
            else {
                String sen = "(" + a + ")" + output + "(" + b + ") " + " = " + ans;
                JOptionPane.showMessageDialog(null, sen, TITLE, JOptionPane.PLAIN_MESSAGE);
            }

            // do this again?
            option = JOptionPane.showConfirmDialog(null, "Do you want to do this again?", TITLE,
                    JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
            if (option != JOptionPane.YES_OPTION)
                break;
        } while (true);
    }

}

class Complex {

    // define two doubles, known as the real part and the imaginary part.
    private double real;
    private double imag;

    // define 4 constructors
    public Complex(double real, double imag) {
        this.real = real;
        this.imag = imag;
    }

    public Complex(double real) {
        this.real = real;
        this.imag = 0;
    }

    public Complex() {
        this(0, 0);
    }

    // the constructor takes a String
    public Complex(String str) {
        String p1 = "\\.*[i]$";
        // Create a Pattern object
        Pattern r1 = Pattern.compile(p1);
        // Now create matcher object.
        Matcher m = r1.matcher(str);
        if (m.find()) {
            if (str.equalsIgnoreCase("i")) {
                this.imag = 1.0;
                this.real = 0.0;
            } else if (str.equalsIgnoreCase("-i")) {
                this.imag = -1.0;
                this.real = 0.0;
            }

            String p2 = "([+-]?(\\d+(\\.\\d+)?|\\.\\d+))[i]";
            Pattern r2 = Pattern.compile(p2);
            Matcher m2 = r2.matcher(str);
            if (m2.find()) {
                this.imag = Double.parseDouble(m2.group(1));
                this.real = 0.0;
            }

            String p3 = "([+-]?(\\d+(\\.\\d+)?|\\.\\d+))(([+-]((\\d+(\\.\\d+)?|\\.\\d+))?))[i]";
            Pattern r3 = Pattern.compile(p3);
            Matcher m3 = r3.matcher(str);
            if (m3.find()) {
                if (m3.group(4).equals("-")) {
                    this.real = Double.parseDouble(m3.group(1));
                    this.imag = -1.0;
                } else if (m3.group(4).equals("+")) {
                    this.real = Double.parseDouble(m3.group(1));
                    this.imag = -1.0;
                } else {
                    this.real = Double.parseDouble(m3.group(1));
                    this.imag = Double.parseDouble(m3.group(4));
                }
            }

        } else {
            this.real = Double.parseDouble(str);
            this.imag = 0.0;
        }
    }

    // define public methods
    public double getReal() {
        return real;
    }

    public double getImag() {
        return imag;
    }

    public Complex add(Complex c) {
        return new Complex((this.real + c.getReal()), (this.imag + c.getImag()));
    }

    public Complex subtract(Complex c) {
        return new Complex((this.real - c.getReal()), (this.imag - c.getImag()));
    }

    public Complex multiply(Complex c) {
        return new Complex((this.real * c.getReal() - this.imag * c.getImag()),
                (this.real * c.getImag() + c.getImag() * c.getImag()));
    }

    public Complex divide(Complex c) {
        double a = this.real;
        double b = this.imag;
        double x = c.getReal();
        double y = c.getImag();
        return new Complex((a * x + b * y) / (x * x + y * y), (b * x - a * y) / (x * x + y * y));
    }

    public double abs() {
        double a = this.getReal();
        double b = this.getImag();
        return Math.sqrt(a * a + b * b);
    }

    public Complex negate() {
        double a = this.getReal();
        double b = this.getImag();
        return new Complex(-a, -b);
    }

    public Complex conjugate() {
        return new Complex(this.getReal(), -this.getImag());
    }

    public double distance(Complex c) {
        double x = this.getReal() - c.getReal();
        double y = this.getImag() - c.getImag();
        return x * x + y * y;
    }

    public boolean equals(Complex c) {
        double minus = (this.abs() > c.abs()) ? (this.abs() - c.abs()) : -(this.abs() - c.abs());
        if (minus / this.abs() < 1E-6)
            return true;
        return false;
    }

    public boolean greaterThan(Complex c) {
        return (this.abs() > c.abs()) ? true : false;
    }

    public boolean lessThan(Complex c) {
        return !this.greaterThan(c);
    }

    public String toString() {
        if (this.getImag() > 0)
            return this.getReal() + "+" + (this.getImag() + "i");
        else if (this.getImag() == 0)
            return this.getReal() + "";
        else
            return this.getReal() + "" + (this.getImag() + "i");
    }
}