Customizing Resource Bundle Loading : ResourceBundle « I18N « Java Tutorial

1. Java Tutorial
2. I18N
3. ResourceBundle

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.Properties;
import java.util.ResourceBundle;
import java.util.Set;

public class XMLResourceBundleControl extends ResourceBundle.Control {
  private static String XML = "xml";

  public List<String> getFormats(String baseName) {
    return Collections.singletonList(XML);
  }

  public ResourceBundle newBundle(String baseName, Locale locale, String format,
      ClassLoader loader, boolean reload) throws IllegalAccessException, InstantiationException,
      IOException {

    if ((baseName == null) || (locale == null) || (format == null) || (loader == null)) {
      throw new NullPointerException();
    }
    ResourceBundle bundle = null;
    if (!format.equals(XML)) {
      return null;
    }

    String bundleName = toBundleName(baseName, locale);
    String resourceName = toResourceName(bundleName, format);
    URL url = loader.getResource(resourceName);
    if (url == null) {
      return null;
    }
    URLConnection connection = url.openConnection();
    if (connection == null) {
      return null;
    }
    if (reload) {
      connection.setUseCaches(false);
    }
    InputStream stream = connection.getInputStream();
    if (stream == null) {
      return null;
    }
    BufferedInputStream bis = new BufferedInputStream(stream);
    bundle = new XMLResourceBundle(bis);
    bis.close();

    return bundle;
  }

  public static void main(String args[]) {
    ResourceBundle bundle = ResourceBundle.getBundle("Strings", new XMLResourceBundleControl());
    String string = bundle.getString("Key");
    System.out.println("Key: " + string);
  }
}

class XMLResourceBundle extends ResourceBundle {
  private Properties props;

  XMLResourceBundle(InputStream stream) throws IOException {
    props = new Properties();
    props.loadFromXML(stream);
  }

  protected Object handleGetObject(String key) {
    return props.getProperty(key);
  }

  public Enumeration<String> getKeys() {
    Set<String> handleKeys = props.stringPropertyNames();
    return Collections.enumeration(handleKeys);
  }
}