package at.gv.egovernment.moa.logging;

/**
 * Provides each thread with a single instance of <code>LoggingContext</code>.
 * 
 * @author Patrick Peck
 * @version $Id$
 */
public class LoggingContextManager {
  /** The single instance of this class. */
  private static LoggingContextManager instance = null;
  
  /** The <code>LoggingContext</code> for each thread. */
  private ThreadLocal context;
  
  /**
   * Get the single instance of the <code>LoggingContextManager</code> class.
   * 
   * @return LoggingContextManager The single instance.
   */
  public static synchronized LoggingContextManager getInstance() {
    if (instance == null) {
      instance = new LoggingContextManager();
    }
    return instance;
  }
  
  /**
   * Creates a new <code>LoggingContextManager</code>.
   * 
   * Protected to disallow direct instantiation.
   */
  protected LoggingContextManager() {
    context = new ThreadLocal();
  }
  
  /**
   * Set the <code>LoggingContext</code> context for the current thread.
   * 
   * @param ctx The <code>LoggingContext</code> for the current thread.
   */
  public void setLoggingContext(LoggingContext ctx) {
    context.set(ctx);
  }
  
  /**
   * Return the <code>LoggingContext</code> for the current thread.
   * 
   * @return LoggingContext The <code>LoggingContext</code> for the current
   * thread, or <code>null</code> if none has been set.
   */
  public LoggingContext getLoggingContext() {
    return (LoggingContext) context.get();
  }

}