How to define JRadioButton label position?

By I Wayan Saryada in Swing 0 Comment

In this code snippet you’ll see how to define JRadioButton label position. By default, the label will be displayed on the right side of the button. In the code below you will see some examples for placing the label on the left side, at the top and the bottom of the JRadioButton.

To define the label position we use the combination of the setHorizontalTextPosition() and setVerticalTextPosition() method and specified the position using one of the available constant in SwingConstants interface.

package org.kodejava.swing;

import javax.swing.*;

public class RadioButtonLabelPosition {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();

        // Create JRadioButton with label on the right
        JRadioButton button1 = new JRadioButton("Button One");
        button1.setHorizontalTextPosition(SwingConstants.RIGHT);

        // Create JRadioButton with label on the left
        JRadioButton button2 = new JRadioButton("Button Two");
        button2.setHorizontalTextPosition(SwingConstants.LEFT);

        // Create JRadioButton with label at the bottom centered.
        JRadioButton button3 = new JRadioButton("Button Three");
        button3.setVerticalTextPosition(SwingConstants.BOTTOM);
        button3.setHorizontalTextPosition(SwingConstants.CENTER);

        // Create JRadioButton with label at the top centered.
        JRadioButton button4 = new JRadioButton("Button Four");
        button4.setVerticalTextPosition(SwingConstants.TOP);
        button4.setHorizontalTextPosition(SwingConstants.CENTER);

        panel.add(button1);
        panel.add(button2);
        panel.add(button3);
        panel.add(button4);

        frame.add(panel);
        frame.setSize(500, 300);
        frame.setVisible(true);
    }
}

Here is a screen capture result of the code snippet above:

JRadioButton Label Position

How to truncate a string after n number of words?

By I Wayan Saryada in Regex 1 Comment 
package org.kodejava.regex;

public class GetNumberOfWordsFromString {
    public static void main(String[] args) {
        String text = "The quick brown fox jumps over the lazy dog.";

        String one = truncateAfterWords(1, text);
        System.out.println("1 = " + one);

        String two = truncateAfterWords(2, text);
        System.out.println("2 = " + two);

        String four = truncateAfterWords(4, text);
        System.out.println("4 = " + four);

        String six = truncateAfterWords(6, text);
        System.out.println("6 = " + six);
    }

    /**
     * Truncate a string after n number of words.
     *
     * @param words number of words to truncate after.
     * @param text  the text.
     * @return truncated text.
     */
    public static String truncateAfterWords(int words, String text) {
        String regex = String.format("^((?:\\W*\\w+){%s}).*$", words);
        return text.replaceAll(regex, "$1");
    }
}

The result of the snippet:

1 = The
2 = The quick
4 = The quick brown fox
6 = The quick brown fox jumps over

How to get random key-value pair from Hashtable?

By I Wayan Saryada in Core API, Util Package 0 Comment 
package org.kodejava.example.util;

import java.util.Hashtable;
import java.util.Random;

public class HashtableGetRandom {
    public static void main(String[] args) {
        // Create a hashtable and put some key-value pair.
        Hashtable<String, String> colors = new Hashtable<>();
        colors.put("black", "#000");
        colors.put("red", "#f00");
        colors.put("green", "#0f0");
        colors.put("blue", "#00f");
        colors.put("white", "#fff");

        // Get a random entry from the hashtable.
        String[] keys = colors.keySet().toArray(new String[colors.size()]);
        String key = keys[new Random().nextInt(keys.length)];
        System.out.println(key + " = " + colors.get(key));
    }
}

How to monitor file or directory changes?

By I Wayan Saryada in Core API, IO 2 Comments 
package org.kodejava.io;

import java.io.IOException;
import java.nio.file.*;

import static java.nio.file.StandardWatchEventKinds.*;

public class FileWatchDemo {
    public static void main(String[] args) {
        try {
            // Creates a instance of WatchService.
            WatchService watcher = FileSystems.getDefault().newWatchService();

            // Registers the logDir below with a watch service.
            Path logDir = Paths.get("F:/Temp/");
            logDir.register(watcher, ENTRY_CREATE, ENTRY_MODIFY, ENTRY_DELETE);

            // Monitor the logDir at listen for change notification.
            while (true) {
                WatchKey key = watcher.take();
                for (WatchEvent<?> event : key.pollEvents()) {
                    WatchEvent.Kind<?> kind = event.kind();

                    if (ENTRY_CREATE.equals(kind)) {
                        System.out.println("Entry was created on log dir.");
                    } else if (ENTRY_MODIFY.equals(kind)) {
                        System.out.println("Entry was modified on log dir.");
                    } else if (ENTRY_DELETE.equals(kind)) {
                        System.out.println("Entry was deleted from log dir.");
                    }
                }
                key.reset();
            }
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }
    }
}

To get the created, modified or deleted file you can see the following example: How to get the file name when using WatchService?.

How to get the file name when using WatchService?

By I Wayan Saryada in Core API, IO 3 Comments 
package org.kodejava.io;

import java.io.IOException;
import java.nio.file.*;

import static java.nio.file.StandardWatchEventKinds.*;

public class WatchServiceGetFilename {
    public static void main(String[] args) {
        try {
            // Create a WatchService and register the logDir path with the
            // WatchService for ENTRY_CREATE.
            WatchService watcher = FileSystems.getDefault().newWatchService();
            Path logDir = Paths.get("F:/Temp");
            logDir.register(watcher, ENTRY_CREATE);

            while (true) {
                WatchKey key;
                try {
                    key = watcher.take();
                } catch (InterruptedException e) {
                    return;
                }

                for (WatchEvent<?> event : key.pollEvents()) {
                    if (event.kind() == ENTRY_CREATE) {
                        // Get the name of created file.
                        WatchEvent<Path> ev = cast(event);
                        Path filename = ev.context();

                        System.out.printf("A new file %s was created.%n",
                                filename.getFileName());
                    }
                }
                key.reset();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @SuppressWarnings("unchecked")
    private static <T> WatchEvent<T> cast(WatchEvent<?> event) {
        return (WatchEvent<T>) event;
    }
}