/*
    * Copyright (c) 1998-2005 The Jgroup Team.
    *
    * This program is free software; you can redistribute it and/or modify
    * it under the terms of the GNU Lesser General Public License version 2 as
    * published by the Free Software Foundation.
    *
    * 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.
   *
   * You should have received a copy of the GNU Lesser General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   *
   */
  package jgroup.util.log;
  
  import static jgroup.util.log.ViewEvent.RecoveryState.FULLY_REPLICATED;
  import static jgroup.util.log.ViewEvent.RecoveryState.NEED_RECOVERY;
  import static jgroup.util.log.ViewEvent.RecoveryState.NEW_MEMBER;
  import static jgroup.util.log.ViewEvent.RecoveryState.NORMAL;
  import static jgroup.util.log.ViewEvent.RecoveryState.TOO_MANY_REPLICAS;
  import jgroup.core.MemberId;
  import jgroup.core.View;
  import jgroup.relacs.config.AppConfig;
  import jgroup.relacs.types.ViewId;
  import jgroup.util.Network;
  
  /**
   * A view event to be logged.
   * 
   * @author Rune Vestvik
   * @author Hein Meling
   */
  public final class ViewEvent
    extends Event
  {
  
    ////////////////////////////////////////////////////////////////////////////////////////////
    // Constants
    ////////////////////////////////////////////////////////////////////////////////////////////
  
    private static final long serialVersionUID = 4049640096401864757L;
  
    /**
     * Supported view change event types.
     */
    public enum Type implements EventType { ARM, Merge, Server, Client }
  
    enum RecoveryState { NEW_MEMBER, NORMAL, NEED_RECOVERY, FULLY_REPLICATED, TOO_MANY_REPLICAS }
  
  
    ////////////////////////////////////////////////////////////////////////////////////////////
    // Fields
    ////////////////////////////////////////////////////////////////////////////////////////////
  
    /**
     * The view event to be logged.
     */
    private final View view;
  
    private int minimalRedundancy;
  
    private int initialRedundancy;
  
    private RecoveryState state;
  
  
    ////////////////////////////////////////////////////////////////////////////////////////////
    // Constructor
    ////////////////////////////////////////////////////////////////////////////////////////////
  
    public ViewEvent(EventType type, View view)
    {
      super(type, "ViewChange");
      this.view = (View) view.clone();
      AppConfig thisApp = AppConfig.getApplication(this.view.getGid());
      try {
        this.minimalRedundancy = thisApp.getMinimalRedundancy();
        this.initialRedundancy = thisApp.getInitialRedundancy();
      } catch (IllegalStateException e) {
        /*
         * Ignored, since we may be running an application without a specified
         * redundancy, e.g. helloserver.
         */
      }
      computeState();
    }
  
  
    ////////////////////////////////////////////////////////////////////////////////////////////
    // Private Methods
    ////////////////////////////////////////////////////////////////////////////////////////////
  
    private void computeState()
    {
      int vsize = view.size();
     if (vsize == initialRedundancy) {
       state = FULLY_REPLICATED;
     } else if (vsize < minimalRedundancy) {
       if (isFirstView())
         state = NEW_MEMBER;
       else
         state = NEED_RECOVERY;
     } else if (vsize > initialRedundancy) {
       state = TOO_MANY_REPLICAS;
     } else if (vsize >= minimalRedundancy && vsize < initialRedundancy) {
       state = NORMAL;
     }
     assert state != null;
   }
 
 
   ////////////////////////////////////////////////////////////////////////////////////////////
   // Access Methods
   ////////////////////////////////////////////////////////////////////////////////////////////
 
   public int getViewSize()
   {
     return view.size();
   }
 
   public long getViewId()
   {
     return view.getVid();
   }
 
   public View getView()
   {
     return view;
   }
 
   public int getGroupId()
   {
     return view.getGid();
   }
 
   /**
    * @return True if this view is the first view installed by the member of this view.
    *   False is returned otherwise.  Meaning that if there is more than one member or
    *   if the single member view is not the first that the member has installed, then
    *   false will be returned.
    */
   public boolean isFirstView()
   {
     if (view.size() == 1) {
       MemberId memb = view.getMembers()[0];
       // Compute the initial vid for this single member
       long theInitialVid = ViewId.create(memb.getEndPoint(), 0);
       return theInitialVid == view.getVid();
     } else {
       return false;
     }
   }
 
   public boolean isFullyReplicated()
   {
     return state == FULLY_REPLICATED;
   }
 
   public boolean isOK()
   {
     return state == NORMAL || state == FULLY_REPLICATED;
   }
 
   public boolean needRecovery()
   {
     return state == NEED_RECOVERY;
   }
 
   public boolean hasTooManyReplicas()
   {
     return state == TOO_MANY_REPLICAS;
   }
 
 
   ////////////////////////////////////////////////////////////////////////////////////////////
   // Methods from Object
   ////////////////////////////////////////////////////////////////////////////////////////////
 
   public String toString()
   {
     StringBuilder buf = commonToString(true);
     commonToString(buf);
     return buf.toString();
   }
 
   /**
    *  Print the content of this view event without the host and time.
    */
   public String shortToString()
   {
     StringBuilder buf = new StringBuilder("ViewEvent");
     commonToString(buf);
     return buf.toString();
   }
 
   protected void commonToString(StringBuilder buf)
   {
     buf.append(" gid=");
     buf.append(view.getGid());
     buf.append(" view.size=");
     buf.append(view.size());
     buf.append(" (");
     buf.append(state);
     buf.append(") vid=");
     buf.append(view.getVid());
     buf.append(" members: ");
     MemberId[] members = view.getMembers();
     for (int i = 0; i < members.length; i++) {
       buf.append(Network.getMachineName(members[i].getCanonicalHostName()));
       buf.append(" ");
     }
   }
 
 
   ////////////////////////////////////////////////////////////////////////////////////////////
   // Serialization Methods
   ////////////////////////////////////////////////////////////////////////////////////////////
 
   /**
    * Override readObject to update the recovery state, given a particular 
    * redundancy configuration.
    */
 //  private void readObject(ObjectInputStream in)
 //    throws IOException, ClassNotFoundException
 //  {
 //    in.defaultReadObject();
 //    computeState();
 //  }
 
 } // END ViewEvent