package at.gv.egovernment.moa.util;

import java.util.Locale;

/**
 * A singleton wrapper around a <code>Message</code> object.
 * 
 * Provides the messages used in the common project.
 * 
 * @author Patrick Peck
 * @version $Id$
 */
public class MessageProvider {
  /** The location of the default message resources. */
  private static final String[] DEFAULT_MESSAGE_RESOURCES =
    { "resources/properties/common_messages" };
  /** The locale of the default message resources. */
  private static final Locale[] DEFAULT_MESSAGE_LOCALES =
    new Locale[] { new Locale("de", "AT") };
  /** The single instance of this class. */
  private static MessageProvider instance;
  
  /** The messages provided by this <code>MessageProvider</code>. */
  private Messages messages;
  
  /**
   * Return the single instance of the <code>MessageProvider</code>.
   * 
   * Intialilizes the <code>MessageProvider</code> with the default message
   * locations: <code>/resources/properties/common_messages</code>.
   * 
   * @return The single <code>MessageProvider</code>.
   */
  public static synchronized MessageProvider getInstance() {
    if (instance == null) {
      instance =
        new MessageProvider(DEFAULT_MESSAGE_RESOURCES, DEFAULT_MESSAGE_LOCALES);
    }
    return instance;
  }

  /**
   * Create a <code>MessageProvider</code>.
   * 
   * @param resourceNames The names of the resources containing the messages.
   * @param locales The corresponding locales.
   */
  protected MessageProvider(String[] resourceNames, Locale[] locales) {
    this.messages = new Messages(resourceNames, locales);
  }

  /**
   * Get the message corresponding to a given message ID.
   *
   * @param messageId The ID of the message.
   * @param parameters The parameters to fill in into the message arguments.
   * @return The formatted message. 
   */
  public String getMessage(String messageId, Object[] parameters) {
    return messages.getMessage(messageId, parameters);
  }

}