/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2009 by ELCA Informatique SA, Av. de la Harpe 22-24,
    * 1000 Lausanne, Switzerland, http://www.elca.ch
    *
    * EL4J is published under the GNU Lesser General Public License (LGPL)
    * Version 2.1. See http://www.gnu.org/licenses/
    *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU Lesser General Public License for more details.
   *
   * For alternative licensing, please contact info@elca.ch
   */
  package ch.elca.el4j.util.socketstatistics;
  
  import java.io.BufferedWriter;
  import java.io.FileWriter;
  import java.io.IOException;
  import java.util.Date;
  import java.util.Iterator;
  import java.util.Set;
  import java.util.SortedSet;
  import java.util.TreeSet;
  
  /**
   * Keeps statistics for all sockets / from all socket connections.
   *
   * @svnLink $Revision: 3990 $;$Date: 2009-11-13 16:36:10 +0100 (Fr, 13. Nov 2009) $;$Author: jonasha $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/socketstatistics/src/main/java/ch/elca/el4j/util/socketstatistics/SocketStatistics.java $
   *
   * @author Jonas Hauenstein (JHN)
   */
  public class SocketStatistics implements SocketStatisticsMXBean {
  
  	/**
  	 * Config: How many seconds to keep the statistics of sockets. Default is 600 seconds = 10 minutes
  	 */
  	private static int s_keepStats = 600;
  
  	/**
  	 * Internal unique id counter for sockets.
  	 */
  	private static long s_socketIdCounter = 0;
  
  	/**
  	 * Number of already closed sockets.
  	 */
  	private static long s_nrofclosedsockets = 0;
  
  	/**
  	 * List of all connections sorted by destruction / closed date (first order). and creation date (second order, if
  	 * not yet closed).
  	 */
  	private static SortedSet<ConnectionStatistics> s_statsbydate = new TreeSet<ConnectionStatistics>();
  
  	/**
  	 * Add a new ConnectionStatics for a socket.
  	 * 
  	 * @return the ConnectionsStatics added to the the set
  	 */
  	public static synchronized ConnectionStatistics addNewConStats() {
  		// explicitly synchronize on list
  		synchronized (s_statsbydate) {
  			long i = getNextID();
  			ConnectionStatistics cs = new ConnectionStatistics(i);
  			s_statsbydate.add(cs);
  			cleanupStats();
  			return cs;
  		}
  	}
  
  	/**
  	 * Fetch next id for socket and increment internal counter.
  	 * 
  	 * @return next unique id
  	 */
  	private static synchronized long getNextID() {
  		return ++s_socketIdCounter;
  	}
  
  	/** {@inheritDoc} */
  	public long getClosedSocketsCount() {
  		return s_nrofclosedsockets;
  	}
  
  	/** {@inheritDoc} */
  	public long getOpenSocketsCount() {
  		return s_socketIdCounter - s_nrofclosedsockets;
  	}
  
  	/** {@inheritDoc} */
  	public Set<ConnectionStatistics> getConnectionStatistics() {
  		return new TreeSet<ConnectionStatistics>(s_statsbydate);
  	}
  
  	/** {@inheritDoc} */
  	public int getKeepStats() {
 		return s_keepStats;
 	}
 
 	/** {@inheritDoc} */
 	public void setKeepStats(int ks) {
 		setKeepStatsS(ks);
 	}
 	
 	/**
 	 * Internal static setter for the keepStats property which defines how many seconds 
 	 * stats of closed sockets are kept.
 	 * 
 	 * @param ks how many seconds closed sockets will be kept in statistics
 	 */
 	private static void setKeepStatsS(int ks) {
 		s_keepStats = ks;
 	}
 
 	/** {@inheritDoc} */
 	public void exportStatisticsCSV(String filepath) {
 		BufferedWriter out = null;
 		try {
 			out = new BufferedWriter(new FileWriter(filepath));
 			out.write("Socket ID;Creation Date;Destruction Date;Remote Adress;Remote Port;Local Port;Bytes received;Bytes sent\n");
 			synchronized (s_statsbydate) {
 				for (ConnectionStatistics cs : s_statsbydate) {
 					out.write(cs.getStatisticsCSV());
 				}
 			}
 		} catch (IOException ex) {
 			ex.printStackTrace();
 		} finally {
 			try {
 				if (out != null) {
 					out.flush();
 					out.close();
 				}
 			} catch (IOException ex) {
 				ex.printStackTrace();
 			}
 		}
 	}
 
 	/** {@inheritDoc} */
 	public void deleteStatistics() {
 		synchronized (s_statsbydate) {
 			s_statsbydate.clear();
 		}
 	}
 
 	/**
 	 * Set a connection as destroyed / closed. Also sets the destruction date / close date of the connection to now
 	 * 
 	 * @param cs
 	 *            the corresponding ConnectionStatics object
 	 */
 	public static synchronized void setConnectionDestroyed(ConnectionStatistics cs) {
 		// explicitly synchronize on list
 		synchronized (s_statsbydate) {
 			// remove element from set
 			s_statsbydate.remove(cs);
 			// set the destruction date
 			cs.setDestroyedDateInt();
 			s_nrofclosedsockets++;
 			// re-enter element in set (to force reordering)
 			s_statsbydate.add(cs);
 		}
 	}
 
 	/**
 	 * Print statistics of all listed sockets to stdout.
 	 */
 	public void showSocketsStats() {
 		cleanupStats();
 		// explicitly synchronize on list
 		synchronized (s_statsbydate) {
 			if (s_statsbydate.isEmpty()) {
 				System.out.println("No statistics available");
 			} else {
 				for (ConnectionStatistics cs : s_statsbydate) {
 					System.out.println(cs.getStatistics());
 				}
 			}
 		}
 	}
 
 	/**
 	 * Get rid of the old ConnectionStatics. Purge those, which are closed longer ago then keepstats
 	 */
 	private static synchronized void cleanupStats() {
 
 		// explicitly synchronize on list
 		synchronized (s_statsbydate) {
 			ConnectionStatistics cs;
 			Date dd;
 			long timecheck = new Date().getTime() - (s_keepStats * 1000);
 			Iterator<ConnectionStatistics> i = s_statsbydate.iterator();
 			// remove elements until one does not match the condition in the
 			// sorted list
 			while (i.hasNext()) {
 				cs = i.next();
 				dd = cs.getDestroyedDateInt();
 				if (dd != null) {
 					if (dd.getTime() < timecheck) {
 						i.remove();
 					} else {
 						break;
 					}
 				} else {
 					break;
 				}
 			}
 		}
 
 	}
 
 }