/**
    * The contents of this file are subject to the Mozilla Public License Version 1.1
    * (the "License"); you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at http://www.mozilla.org/MPL/
    * Software distributed under the License is distributed on an "AS IS" basis,
    * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for the
    * specific language governing rights and limitations under the License.
    *
    * The Original Code is ""  Description:
   * ""
   *
   * The Initial Developer of the Original Code is University Health Network. Copyright (C)
   * 2001.  All Rights Reserved.
   *
   * Contributor(s): ______________________________________.
   *
   * Alternatively, the contents of this file may be used under the terms of the
   * GNU General Public License (the  "GPL"), in which case the provisions of the GPL are
   * applicable instead of those above.  If you wish to allow use of your version of this
   * file only under the terms of the GPL and not to allow others to use your version
   * of this file under the MPL, indicate your decision by deleting  the provisions above
   * and replace  them with the notice and other provisions required by the GPL License.
   * If you do not delete the provisions above, a recipient may use your version of
   * this file under either the MPL or the GPL.
   */
  package ca.uhn.hl7v2.testpanel.util;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.ConcurrentLinkedQueue;
  
  import javax.swing.SwingUtilities;
  
  import org.apache.log4j.BasicConfigurator;
  import org.apache.log4j.PatternLayout;
  import org.apache.log4j.WriterAppender;
  import org.apache.log4j.spi.LoggingEvent;
  
  public class SwingLogAppender extends WriterAppender {
  
  	private static Map<String, ArrayList<ILogListener>> listeners = new HashMap<String, ArrayList<ILogListener>>();
  
  	private ConcurrentLinkedQueue<LoggingEvent> buf;
  
  	public SwingLogAppender() {
  		super();
  		this.buf = new ConcurrentLinkedQueue<LoggingEvent>();
  		setLayout(new PatternLayout(PatternLayout.TTCC_CONVERSION_PATTERN));
  		BasicConfigurator.configure(this);
  	}
  
  	@Override
  	public void append(LoggingEvent event) {
  		buf.offer(event);
  
  		// if (getLayout().ignoresThrowable()) {
  		// String[] exception = event.getThrowableStrRep();
  		// if (exception != null) {
  		// for (String line : exception) {
  		// buf.offer(line);
  		// }
  		// }
  		// }
  		display();
  	}
  
  	void display() {
  		SwingUtilities.invokeLater(new Runnable() {
  
  			public void run() {
  				while (!buf.isEmpty()) {
  					LoggingEvent next = buf.poll();
  					String formattedLine = getLayout().format(next);
  					String ndc = next.getNDC();
  					fireEvent("", next, formattedLine);
  					if (ndc != null) {
  						fireEvent(ndc, next, formattedLine);
  					}
  				}
  				buf.clear();
  			}
  
  		});
  	}
  
  	private void fireEvent(String theNdc, LoggingEvent theEvent, String theFormatted) {
  		ArrayList<ILogListener> list = listeners.get(theNdc);
  		if (list != null) {
  			for (ILogListener next : list) {
  				next.handle(theEvent, theFormatted);
  			}
  		}
  	}
  
  	public static void addListener(ILogListener theListener) {
  		addListener("", theListener);
  	}
  
 	public static void addListener(String theNdc, ILogListener theListener) {
 		if (!listeners.containsKey(theNdc)) {
 			listeners.put(theNdc, new ArrayList<ILogListener>());
 		}
 		listeners.get(theNdc).add(theListener);
 	}
 
 	public static void removeListener(ILogListener theListener) {
 		removeListener("", theListener);
 	}
 
 	public static void removeListener(String theNdc, ILogListener theListener) {
 		listeners.get(theNdc).remove(theListener);
 	}
 
 	public interface ILogListener {
 
 		void handle(LoggingEvent theEvent, String theFormattedLine);
 
 	}
 
 }