code: /**
  Copyright (c) 2007-2013 Alysson Bessani, Eduardo Alchieri, Paulo Sousa, and the authors indicated in the @author tags
  
  Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  */
  package bftsmart.reconfiguration;
  
  import java.io.BufferedReader;
  import java.io.ByteArrayOutputStream;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.ObjectOutputStream;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Scanner;
  import java.util.StringTokenizer;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import bftsmart.communication.server.ServerConnection;
  import bftsmart.reconfiguration.views.View;
  
  /**
   *
   * @author eduardo
   */
  public class ViewManager {
      private final static org.apache.log4j.Logger logger = org.apache.log4j.Logger.getLogger(ViewManager.class);
  
      private int id;
      private Reconfiguration rec = null;
      //private Hashtable<Integer, ServerConnection> connections = new Hashtable<Integer, ServerConnection>();
      private ServerViewController controller;
      //Need only inform those that are entering the systems, as those already
      //in the system will execute the reconfiguration request
      private List<Integer> addIds = new LinkedList<Integer>();
  
      public ViewManager() {
          this("config");
      }
  
      public ViewManager(String configHome) {
          this.id = loadID(configHome);
          this.controller = new ServerViewController(id, configHome);
          this.rec = new Reconfiguration(id);
      }
  
      public void connect(){
          this.rec.connect();
      }
      
      private int loadID(String configHome) {
          try {
              String path = "";
              String sep = System.getProperty("file.separator");
              if (configHome == null || configHome.equals("")) {
                  path = "config" + sep + "system.config";
              } else {
                  path = configHome + sep + "system.config";
              }
              FileReader fr = new FileReader(path);
              BufferedReader rd = new BufferedReader(fr);
              String line = null;
              while ((line = rd.readLine()) != null) {
                  if (!line.startsWith("#")) {
                      StringTokenizer str = new StringTokenizer(line, "=");
                      if (str.countTokens() > 1
                              && str.nextToken().trim().equals("system.ttp.id")) {
                          fr.close();
                          rd.close();
                          return Integer.parseInt(str.nextToken().trim());
                      }
                  }
              }
              fr.close();
              rd.close();
              return -1;
          } catch (Exception e) {
  //            e.printStackTrace(System.out);
              logger.error(e);
              return -1;
          }
      }
  
      public void addServer(int id, String ip, int port) {
          this.controller.getStaticConf().addHostInfo(id, ip, port);
          rec.addServer(id, ip, port);
          addIds.add(id);
      }
  
      public void removeServer(int id) {
          rec.removeServer(id);
      }
  
      public void setF(int f) {
          rec.setF(f);
      }
  
      public void executeUpdates() {
          connect();
          ReconfigureReply r = rec.execute();
          View v = r.getView();
          logger.info("New view f: " + v.getF());
  
          VMMessage msg = new VMMessage(id, r);
  
          if (addIds.size() > 0) { 
              sendResponse(addIds.toArray(new Integer[1]), msg);
              addIds.clear();
          }
  
  
      }
  
      private ServerConnection getConnection(int remoteId) {
           return new ServerConnection(controller, null, remoteId, null, null);
      }
  
      public void sendResponse(Integer[] targets, VMMessage sm) {
          ByteArrayOutputStream bOut = new ByteArrayOutputStream();
  
          try {
              new ObjectOutputStream(bOut).writeObject(sm);
          } catch (IOException ex) {
              logger.error("", ex);
          }
  
          byte[] data = bOut.toByteArray();
  
          for (Integer i : targets) {
              //br.ufsc.das.tom.util.logger.info("(ServersCommunicationLayer.send) Sending msg to replica "+i);
              try {
                  if (i.intValue() != id) {
                      getConnection(i.intValue()).send(data, true);
                  }
              } catch (InterruptedException ex) {
                 // logger.error("", ex);
                  logger.warn(ex);
              }
          }
          //br.ufsc.das.tom.util.logger.info("(ServersCommunicationLayer.send) Finished sending messages to replicas");
      }
  
      public void close() {
          rec.close();
      }
  
      public static void main(String[] args) {
  
          ViewManager viewManager = null;
  
          if (args.length > 0) {
              viewManager = new ViewManager(args[0]);
          } else {
              viewManager = new ViewManager("");
          }
          
          Scanner scan = new Scanner(System.in);
          String str = null;
          do {
              str = scan.nextLine();
              String cmd = "";
              int arg = -1;
              try {
                  StringTokenizer token = new StringTokenizer(str);
                  cmd = token.nextToken();
                  arg = Integer.parseInt(token.nextToken());
              } catch (Exception e) {
              }
  
              if (arg >= 0) {
                  if (cmd.equals("add")) {
  
                      int port = (arg * 10) + 11000;
                      viewManager.addServer(arg, "127.0.0.1", port);
                  } else if (cmd.equals("rem")) {
                      viewManager.removeServer(arg);
                  }
  
                  viewManager.executeUpdates();
              }
  
          } while (!str.equals("exit"));
          viewManager.close();
          System.exit(0);
      }
      
  }
  