How do I create a Hello World Applet?

By Wayan in Applet, Core API 0 Comment

The code below demonstrate the very basic of Java applet. Applet is a small Java application that can be embedded on the web browser.

package org.kodejava.applet;

import java.applet.*;
import java.awt.*;

public class HelloWorldApplet extends Applet {
    public void init() {
    }

    public void start() {
    }

    public void stop() {
    }

    public void destroy() {
    }

    public void paint(Graphics g) {
        g.setColor(Color.GREEN);
        g.drawString("Hello World", 50, 100);
    }
}

To display the applet we need to create an HTML document. Here is a simple example of the document.

<!DOCTYPE html>
<html lang="en">
<head>
    <title>Hello World Applet</title>
</head>

<body>
<applet
        code="org.kodejava.applet.HelloWorldApplet"
        height="250"
        width="250">
</applet>
</body>
</html>

You can now load the applet in your browser or by using the appletviewer utility.

appletviewer.exe hello-world-applet.html
** Deprecated: The Applet API is deprecated since JDK 9, no replacement.

How do I get the available font family names?

By Wayan in AWT, Core API 0 Comment 
package org.kodejava.awt;

import java.awt.GraphicsEnvironment;

public class FontFamilyNameList {
    public static void main(String[] args) {
        // Get all available font family names from GraphicsEnvironment
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        String[] familyNames = ge.getAvailableFontFamilyNames();

        // Iterates familyNames array to display the available font's family names
        for (String familyName : familyNames) {
            System.out.println("Family name: " + familyName);
        }
    }
}

Some font family names are shown below:

Family name: Agency FB
Family name: Algerian
Family name: Arial
Family name: Arial Black
Family name: Arial Narrow
Family name: Arial Rounded MT Bold
Family name: Bahnschrift
Family name: Baskerville Old Face
Family name: Bauhaus 93
Family name: Bell MT
...

How do I get the available font names?

By Wayan in AWT, Core API 0 Comment 
package org.kodejava.awt;

import java.awt.Font;
import java.awt.GraphicsEnvironment;

public class FontNameList {
    public static void main(String[] args) {
        // Get all available fonts from GraphicsEnvironment
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        Font[] fonts = ge.getAllFonts();

        // Iterates all available fonts and get their name and family name
        for (Font font : fonts) {
            String fontName = font.getName();
            String familyName = font.getFamily();

            System.out.println("Font: " + fontName + "; family: " + familyName);
        }
    }
}

Here are some fonts name printed from the code snippet above:

Font: Agency FB; family: Agency FB
Font: Agency FB Bold; family: Agency FB
Font: Algerian; family: Algerian
Font: Arial; family: Arial
Font: Arial Black; family: Arial Black
Font: Arial Bold; family: Arial
Font: Arial Bold Italic; family: Arial
Font: Arial Italic; family: Arial
Font: Arial Narrow; family: Arial Narrow
Font: Arial Narrow Bold; family: Arial Narrow
...

How do I parse a number for a locale?

By Wayan in Core API, Text Package 0 Comment 
package org.kodejava.text;

import java.util.Locale;
import java.text.NumberFormat;
import java.text.ParseException;

public class LocaleNumberParse {
    public static void main(String[] args) {
        try {
            // In this example we are trying to parse a number string in a
            // defined format. Basically we want to covert the string for a
            // locale into a correct number value.
            Number number =
                NumberFormat.getNumberInstance(Locale.JAPAN).parse("25,000.75");

            // Just do some stuff with the number from the parse process
            if (number instanceof Long) {
                System.out.println("This number is instanceof Long and the " +
                    "value is: " + number.longValue());
            } else if (number instanceof Double) {
                System.out.println("This number is instanceof Double and the " +
                    "value is: " + number.doubleValue());
            }
        } catch (ParseException e) {
            e.printStackTrace();
        }

    }
}

The code snippet print out the following result:

This number is instanceof Double and the value is: 25000.75

How do I format a number for a locale?

By Wayan in Core API, Text Package 0 Comment 
package org.kodejava.text;

import java.util.Locale;
import java.text.NumberFormat;

public class LocaleNumberFormat {
    public static void main(String[] args)  {
        // Format number for Italy locale. In Italy locale the decimal point
        // symbol is a comma.
        NumberFormat formatter = NumberFormat.getNumberInstance(Locale.ITALY);
        try {
            String number = formatter.format(195325.75);
            System.out.println("Number in Italy: " + number);
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }

        // Format number for Japan locale. In Japan locale the decimal point
        // symbol is a dot.
        formatter = NumberFormat.getNumberInstance(Locale.JAPAN);
        try {
            String number = formatter.format(195325.75);
            System.out.println("Number in Japan: " + number);
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }
    }
}

The code snippet output:

Number in Italy: 195.325,75
Number in Japan: 195,325.75