MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

import java.awt.Color;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;
import javax.swing.text.AttributeSet;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;

public class MainClass {
    public static void main(String argv[]) {

        ColorPane pane = new ColorPane();
        for (int n = 1; n <= 400; n += 1) {
            if (isPrime(n)) {
                pane.append(Color.red, String.valueOf(n) + ' ');
            } else if (isPerfectSquare(n)) {
                pane.append(Color.blue, String.valueOf(n) + ' ');
            } else {
                pane.append(Color.black, String.valueOf(n) + ' ');
            }
        }

        JFrame f = new JFrame("ColorPane example");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setContentPane(new JScrollPane(pane));
        f.setSize(600, 400);
        f.setVisible(true);
    }

    public static boolean isPrime(int n) {
        if (n < 2)
            return false;
        double max = Math.sqrt(n);
        for (int j = 2; j <= max; j += 1)
            if (n % j == 0)
                return false; // j is a factor
        return true;
    }

    public static boolean isPerfectSquare(int n) {
        int j = 1;
        while (j * j < n && j * j > 0)
            j += 1;
        return (j * j == n);
    }

}

class ColorPane extends JTextPane {

    public void appendNaive(Color c, String s) {
        SimpleAttributeSet aset = new SimpleAttributeSet();
        StyleConstants.setForeground(aset, c);

        int len = getText().length();
        setCaretPosition(len);
        setCharacterAttributes(aset, false);
        replaceSelection(s);
    }

    public void append(Color c, String s) {
        StyleContext sc = StyleContext.getDefaultStyleContext();
        AttributeSet aset = sc.addAttribute(SimpleAttributeSet.EMPTY, StyleConstants.Foreground, c);

        int len = getDocument().getLength();
        setCaretPosition(len);
        setCharacterAttributes(aset, false);
        replaceSelection(s);
    }

}