Improved code for shuting down the client if the servers are not available......

Improved code for shuting down the client if the servers are not available... additionally, exchanged Hastables by HashMaps

src/navigators/smart/communication/client/netty/NettyClientPipelineFactory.java

@@ -18,9 +18,9 @@
 
 package navigators.smart.communication.client.netty;
 
+import java.util.HashMap;
 import static org.jboss.netty.channel.Channels.pipeline;
 
-import java.util.Hashtable;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
@@ -41,7 +41,7 @@ public class NettyClientPipelineFactory implements ChannelPipelineFactory {
 
     NettyClientServerCommunicationSystemClientSide ncs;
     boolean isClient;
-    Hashtable sessionTable;
+    HashMap sessionTable;
     SecretKey authKey;
     int macLength;
     int signatureLength;
@@ -53,7 +53,7 @@ public class NettyClientPipelineFactory implements ChannelPipelineFactory {
     ReentrantReadWriteLock rl;
     ReentrantLock lock;
 
-    public NettyClientPipelineFactory(NettyClientServerCommunicationSystemClientSide ncs, boolean isClient, Hashtable sessionTable, SecretKey authKey, int macLength, ViewManager manager, ReentrantReadWriteLock rl, int signatureLength, ReentrantLock lock) {
+    public NettyClientPipelineFactory(NettyClientServerCommunicationSystemClientSide ncs, boolean isClient, HashMap sessionTable, SecretKey authKey, int macLength, ViewManager manager, ReentrantReadWriteLock rl, int signatureLength, ReentrantLock lock) {
         this.ncs = ncs;
         this.isClient = isClient;
         this.sessionTable = sessionTable;

src/navigators/smart/communication/client/netty/NettyClientServerCommunicationSystemClientSide.java

@@ -21,20 +21,17 @@ import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.io.ObjectOutputStream;
-import java.net.ConnectException;
-import java.nio.channels.ClosedChannelException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
 import java.security.PrivateKey;
 import java.security.Signature;
 import java.security.spec.InvalidKeySpecException;
 import java.util.Enumeration;
-import java.util.Hashtable;
+import java.util.HashMap;
+import java.util.Iterator;
 import java.util.concurrent.Executors;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 
 import javax.crypto.Mac;
 import javax.crypto.SecretKey;
@@ -45,6 +42,7 @@ import navigators.smart.communication.client.CommunicationSystemClientSide;
 import navigators.smart.communication.client.ReplyReceiver;
 import navigators.smart.reconfiguration.ViewManager;
 import navigators.smart.tom.core.messages.TOMMessage;
+import navigators.smart.tom.util.Logger;
 import navigators.smart.tom.util.TOMUtil;
 
 import org.jboss.netty.bootstrap.ClientBootstrap;
@@ -70,12 +68,10 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
     private static final String PASSWORD = "newcs";
     //private static final int BENCHMARK_PERIOD = 10000;
     protected ReplyReceiver trr;
-
     //******* EDUARDO BEGIN **************//
     private ViewManager manager;
     //******* EDUARDO END **************//
-
-    private Hashtable sessionTable;
+    private HashMap sessionTable = new HashMap();
     private ReentrantReadWriteLock rl;
     private SecretKey authKey;
     //the signature engine used in the system
@@ -92,7 +88,6 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
             authKey = fac.generateSecret(spec);
 
             this.manager = manager;
-            this.sessionTable = new Hashtable();
             //this.st = new Storage(BENCHMARK_PERIOD);
             this.rl = new ReentrantReadWriteLock();
             Mac macDummy = Mac.getInstance(manager.getStaticConf().getHmacAlgorithm());
@@ -110,10 +105,11 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
 
                     bootstrap.setOption("tcpNoDelay", true);
                     bootstrap.setOption("keepAlive", true);
+                    bootstrap.setOption("connectTimeoutMillis", 10000);
 
                     // Set up the default event pipeline.
                     bootstrap.setPipelineFactory(new NettyClientPipelineFactory(this, true, sessionTable,
-                        authKey, macDummy.getMacLength(), manager, rl, signatureLength, new ReentrantLock()));
+                            authKey, macDummy.getMacLength(), manager, rl, signatureLength, new ReentrantLock()));
 
                     //******* EDUARDO BEGIN **************//
 
@@ -126,92 +122,30 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
                     Mac macReceive = Mac.getInstance(manager.getStaticConf().getHmacAlgorithm());
                     macReceive.init(authKey);
                     NettyClientServerSession cs = new NettyClientServerSession(future.getChannel(), macSend,
-                        macReceive, currV[i], manager.getStaticConf().getRSAPublicKey(currV[i]), new ReentrantLock());
+                            macReceive, currV[i], manager.getStaticConf().getRSAPublicKey(currV[i]), new ReentrantLock());
                     sessionTable.put(currV[i], cs);
 
                     System.out.println("Connecting to replica " + currV[i] + " at " + manager.getRemoteAddress(currV[i]));
                     //******* EDUARDO END **************//
 
-
                     future.awaitUninterruptibly();
 
-                }catch (java.lang.NullPointerException ex){
-                    System.out.println("Deve resolver o problema, e acho que não trás outras implicações :-), " +
-                            "mas temos que fazer os servidores armazenarem as view em um lugar default.");
-
-                } catch (InvalidKeyException ex) {
-                    Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
-                }
-            }
-        } catch (InvalidKeySpecException ex) {
-            Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
-        } catch (NoSuchAlgorithmException ex) {
-            Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
-        }
-    }
-
-
-
-
-    /*public NettyClientServerCommunicationSystemClientSide(ViewManager manager) {
-        try {
-            SecretKeyFactory fac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
-            PBEKeySpec spec = new PBEKeySpec(PASSWORD.toCharArray());
-            authKey = fac.generateSecret(spec);
-
-            this.manager = manager;
-            this.sessionTable = new Hashtable();
-            //this.st = new Storage(BENCHMARK_PERIOD);
-            this.rl = new ReentrantReadWriteLock();
-            Mac macDummy = Mac.getInstance(manager.getStaticConf().getHmacAlgorithm());
-            signatureLength = TOMUtil.getSignatureSize(manager);
-
-
-            int[] currV = manager.getCurrentViewProcesses();
-            for (int i = 0; i < currV.length; i++) {
-                try {
-                    // Configure the client.
-                    ClientBootstrap bootstrap = new ClientBootstrap(
-                            new NioClientSocketChannelFactory(
-                            Executors.newCachedThreadPool(),
-                            Executors.newCachedThreadPool()));
-
-                    bootstrap.setOption("tcpNoDelay", true);
-                    bootstrap.setOption("keepAlive", true);
-
-                    // Set up the default event pipeline.
-                    bootstrap.setPipelineFactory(new NettyClientPipelineFactory(this, true, sessionTable, authKey, macDummy.getMacLength(), manager, rl, signatureLength, new ReentrantLock()));
-
-                    //******* EDUARDO BEGIN **************
-
-                    // Start the connection attempt.
-                    ChannelFuture future = bootstrap.connect(manager.getStaticConf().getRemoteAddress(currV[i]));
-
-                    //creates MAC stuff
-                    Mac macSend = Mac.getInstance(manager.getStaticConf().getHmacAlgorithm());
-                    macSend.init(authKey);
-                    Mac macReceive = Mac.getInstance(manager.getStaticConf().getHmacAlgorithm());
-                    macReceive.init(authKey);
-                    NettyClientServerSession cs = new NettyClientServerSession(future.getChannel(), macSend, macReceive, currV[i], manager.getStaticConf().getRSAPublicKey(currV[i]), new ReentrantLock());
-                    sessionTable.put(currV[i], cs);
-
-                    System.out.println("Connecting to replica " + currV[i] + " at " + manager.getStaticConf().getRemoteAddress(currV[i]));
-                    //******* EDUARDO END **************
-
-
-                    future.awaitUninterruptibly();
+                    if (!future.isSuccess()) {
+                        System.err.println("Impossible to connect to " + currV[i]);
+                    }
 
+                } catch (java.lang.NullPointerException ex) {
+                    //What the fuck is this??? This is not possible!!!
+                    System.err.println("Deve resolver o problema, e acho que não trás outras implicações :-), "
+                            + "mas temos que fazer os servidores armazenarem as view em um lugar default.");
 
                 } catch (InvalidKeyException ex) {
-                    Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
                 }
             }
         } catch (InvalidKeySpecException ex) {
-            Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
         } catch (NoSuchAlgorithmException ex) {
-            Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
         }
-    }*/
+    }
 
     //TODO: Falta fechar as conexoes para servidores q sairam
     public void updateConnections() {
@@ -234,6 +168,7 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
 
                         bootstrap.setOption("tcpNoDelay", true);
                         bootstrap.setOption("keepAlive", true);
+                        bootstrap.setOption("connectTimeoutMillis", 10000);
 
                         // Set up the default event pipeline.
                         bootstrap.setPipelineFactory(new NettyClientPipelineFactory(this, true, sessionTable, authKey, macDummy.getMacLength(), manager, rl, signatureLength, new ReentrantLock()));
@@ -254,27 +189,21 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
                         System.out.println("Connecting to replica " + currV[i] + " at " + manager.getRemoteAddress(currV[i]));
                         //******* EDUARDO END **************//
 
-
                         future.awaitUninterruptibly();
 
-
                     } catch (InvalidKeyException ex) {
-                        Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
                     }
                 }
             }
         } catch (NoSuchAlgorithmException ex) {
-            Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
         }
     }
 
     @Override
-    public void exceptionCaught(
-            ChannelHandlerContext ctx, ExceptionEvent e) {
-
-        if (!(e.getCause() instanceof ClosedChannelException) && !(e.getCause() instanceof ConnectException)) {
-            e.getCause().printStackTrace();
-        }
+    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {
+        //if (!(e.getCause() instanceof ClosedChannelException) && !(e.getCause() instanceof ConnectException)) {
+        e.getCause().getMessage();
+        //}
     }
 
     @Override
@@ -299,18 +228,17 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
         if (this.closed) {
             return;
         }
+
         try {
             //sleeps 10 seconds before trying to reconnect
             Thread.sleep(10000);
         } catch (InterruptedException ex) {
-            Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
         }
-        //System.out.println("Channel closed");
+
         rl.writeLock().lock();
-        //tries to reconnect the channel
-        Enumeration sessionElements = sessionTable.elements();
-        while (sessionElements.hasMoreElements()) {
-            NettyClientServerSession ncss = (NettyClientServerSession) sessionElements.nextElement();
+        Iterator sessions = sessionTable.values().iterator();
+        while (sessions.hasNext()) {
+            NettyClientServerSession ncss = (NettyClientServerSession) sessions.next();
             if (ncss.getChannel() == ctx.getChannel()) {
                 try {
 
@@ -331,9 +259,8 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
                     NettyClientServerSession cs = new NettyClientServerSession(future.getChannel(), macSend, macReceive, ncss.getReplicaId(), manager.getStaticConf().getRSAPublicKey(ncss.getReplicaId()), new ReentrantLock());
                     sessionTable.remove(ncss.getReplicaId());
                     sessionTable.put(ncss.getReplicaId(), cs);
-                //System.out.println("RE-Connecting to replica "+ncss.getReplicaId()+" at " + conf.getRemoteAddress(ncss.getReplicaId()));
+                    //System.out.println("RE-Connecting to replica "+ncss.getReplicaId()+" at " + conf.getRemoteAddress(ncss.getReplicaId()));
                 } catch (NoSuchAlgorithmException ex) {
-                    Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
                 }
             }
 
@@ -347,10 +274,12 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
         rl.writeLock().unlock();
     }
 
+    @Override
     public void setReplyReceiver(ReplyReceiver trr) {
         this.trr = trr;
     }
 
+    @Override
     public void send(boolean sign, int[] targets, TOMMessage sm, boolean serializeClassHeaders) {
         if (sm.serializedMessage == null) {
             //serialize message
@@ -374,7 +303,7 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
                 data = baos.toByteArray();
                 sm.serializedMessage = data;
             } catch (IOException ex) {
-                Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
+                Logger.println("Impossible to serialize message: " + sm);
             } finally {
                 try {
                     if (dos != null) {
@@ -384,7 +313,6 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
                         oos.close();
                     }
                 } catch (IOException ex) {
-                    Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
                 }
             }
         } else {
@@ -399,6 +327,7 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
             sm.serializedMessageSignature = data2;
         }
 
+        int sent = 0;
         for (int i = targets.length - 1; i >= 0; i--) {
             /**********************************************************/
             /********************MALICIOUS CODE************************/
@@ -420,27 +349,16 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
             if (channel.isConnected()) {
                 sm.signed = sign;
                 channel.write(sm);
+                sent++;
             } else {
-             //System.out.println("WARNING: channel is not connected");
+                Logger.println("Channel to " + targets[i] + " is not connected");
             }
+
+        }
+        
+        if (sent < manager.getCurrentViewF() + 1) {
+            throw new RuntimeException("Impossible to connect to servers!");
         }
-    /*
-    //statistics about signature execution time
-    count++;
-    if (count % BENCHMARK_PERIOD == 0) {
-    int myId = conf.getProcessId();
-    System.out.println("--Signature benchmark:--");
-    System.out.println("(" + myId + ")Average time for " + BENCHMARK_PERIOD + " signatures (-10%) = " + this.st.getAverage(true) / 1000 + " us ");
-    System.out.println("(" + myId + ")Standard desviation for " + BENCHMARK_PERIOD + " signatures (-10%) = " + this.st.getDP(true) / 1000 + " us ");
-    System.out.println("(" + myId + ")Average time for " + BENCHMARK_PERIOD + " signatures (all samples) = " + this.st.getAverage(false) / 1000 + " us ");
-    System.out.println("(" + myId + ")Standard desviation for " + BENCHMARK_PERIOD + " signatures (all samples) = " + this.st.getDP(false) / 1000 + " us ");
-    System.out.println("(" + myId + ")Maximum time for " + BENCHMARK_PERIOD + " signatures (-10%) = " + this.st.getMax(true) / 1000 + " us ");
-    System.out.println("(" + myId + ")Maximum time for " + BENCHMARK_PERIOD + " signatures (all samples) = " + this.st.getMax(false) / 1000 + " us ");
-    System.out.println("(" + myId + ")----------------------------------------------------------------------");
-    count = 0;
-    st.reset();
-    }
-     */
     }
 
     public void sign(TOMMessage sm) {
@@ -455,12 +373,10 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
             data = baos.toByteArray();
             sm.serializedMessage = data;
         } catch (IOException ex) {
-            Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
         } finally {
             try {
                 dos.close();
             } catch (IOException ex) {
-                Logger.getLogger(NettyClientServerCommunicationSystemClientSide.class.getName()).log(Level.SEVERE, null, ex);
             }
         }
 
@@ -470,23 +386,6 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
         //******* EDUARDO END **************//
 
         sm.serializedMessageSignature = data2;
-    /*
-    //statistics about signature execution time
-    count++;
-    if (count % BENCHMARK_PERIOD == 0) {
-    int myId = conf.getProcessId();
-    System.out.println("--Signature benchmark:--");
-    System.out.println("(" + myId + ")Average time for " + BENCHMARK_PERIOD + " signatures (-10%) = " + this.st.getAverage(true) / 1000 + " us ");
-    System.out.println("(" + myId + ")Standard desviation for " + BENCHMARK_PERIOD + " signatures (-10%) = " + this.st.getDP(true) / 1000 + " us ");
-    System.out.println("(" + myId + ")Average time for " + BENCHMARK_PERIOD + " signatures (all samples) = " + this.st.getAverage(false) / 1000 + " us ");
-    System.out.println("(" + myId + ")Standard desviation for " + BENCHMARK_PERIOD + " signatures (all samples) = " + this.st.getDP(false) / 1000 + " us ");
-    System.out.println("(" + myId + ")Maximum time for " + BENCHMARK_PERIOD + " signatures (-10%) = " + this.st.getMax(true) / 1000 + " us ");
-    System.out.println("(" + myId + ")Maximum time for " + BENCHMARK_PERIOD + " signatures (all samples) = " + this.st.getMax(false) / 1000 + " us ");
-    System.out.println("(" + myId + ")----------------------------------------------------------------------");
-    count = 0;
-    st.reset();
-    }
-     */
     }
 
     public byte[] signMessage(PrivateKey key, byte[] message) {
@@ -509,11 +408,12 @@ public class NettyClientServerCommunicationSystemClientSide extends SimpleChanne
         }
     }
 
+    @Override
     public void close() {
         this.closed = true;
-        Enumeration sessionElements = sessionTable.elements();
-        while (sessionElements.hasMoreElements()) {
-            NettyClientServerSession ncss = (NettyClientServerSession) sessionElements.nextElement();
+        Iterator sessions = sessionTable.values().iterator();
+        while (sessions.hasNext()) {
+            NettyClientServerSession ncss = (NettyClientServerSession) sessions.next();
             ncss.getChannel().close();
         }
     }

src/navigators/smart/communication/client/netty/NettyClientServerCommunicationSystemServerSide.java

@@ -27,7 +27,7 @@ import java.security.NoSuchAlgorithmException;
 import java.security.spec.InvalidKeySpecException;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -75,7 +75,7 @@ public class NettyClientServerCommunicationSystemServerSide extends SimpleChanne
 
     private static final String PASSWORD = "newcs";
     private RequestReceiver requestReceiver;
-    private Hashtable sessionTable;
+    private HashMap sessionTable;
     private ReentrantReadWriteLock rl;
     private SecretKey authKey;
     //private long numReceivedMsgs = 0;
@@ -94,7 +94,7 @@ public class NettyClientServerCommunicationSystemServerSide extends SimpleChanne
             authKey = fac.generateSecret(spec);
 
             this.manager = manager;
-            sessionTable = new Hashtable();
+            sessionTable = new HashMap();
             rl = new ReentrantReadWriteLock();
 
             //Configure the server.

src/navigators/smart/communication/client/netty/NettyServerPipelineFactory.java

@@ -18,6 +18,7 @@
 
 package navigators.smart.communication.client.netty;
 
+import java.util.HashMap;
 import static org.jboss.netty.channel.Channels.pipeline;
 
 import java.util.Hashtable;
@@ -39,7 +40,7 @@ public class NettyServerPipelineFactory implements ChannelPipelineFactory {
 
     NettyClientServerCommunicationSystemServerSide ncs;
     boolean isClient;
-    Hashtable sessionTable;
+    HashMap sessionTable;
     SecretKey authKey;
     int macLength;
     int signatureLength;
@@ -47,7 +48,7 @@ public class NettyServerPipelineFactory implements ChannelPipelineFactory {
     ReentrantReadWriteLock rl;
     ReentrantLock lock;
 
-    public NettyServerPipelineFactory(NettyClientServerCommunicationSystemServerSide ncs, boolean isClient, Hashtable sessionTable, SecretKey authKey, int macLength, ReconfigurationManager manager, ReentrantReadWriteLock rl, int signatureLength, ReentrantLock lock) {
+    public NettyServerPipelineFactory(NettyClientServerCommunicationSystemServerSide ncs, boolean isClient, HashMap sessionTable, SecretKey authKey, int macLength, ReconfigurationManager manager, ReentrantReadWriteLock rl, int signatureLength, ReentrantLock lock) {
         this.ncs = ncs;
         this.isClient = isClient;
         this.sessionTable = sessionTable;

src/navigators/smart/communication/client/netty/NettyTOMMessageDecoder.java

@@ -27,7 +27,7 @@ import java.security.NoSuchAlgorithmException;
 import java.security.PublicKey;
 import java.security.Signature;
 import java.util.Arrays;
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.logging.Level;
@@ -61,7 +61,7 @@ public class NettyTOMMessageDecoder extends FrameDecoder {
     //private final int BENCHMARK_PERIOD = 10000;
 
     private boolean isClient;
-    private Hashtable sessionTable;
+    private HashMap sessionTable;
     private SecretKey authKey;
     //private Storage st;
     private int macSize;
@@ -81,7 +81,7 @@ public class NettyTOMMessageDecoder extends FrameDecoder {
     private Signature signatureEngine;
     private boolean useMAC;
 
-    public NettyTOMMessageDecoder(boolean isClient, Hashtable sessionTable, SecretKey authKey, int macLength, ViewManager manager, ReentrantReadWriteLock rl, int signatureLength, boolean useMAC){
+    public NettyTOMMessageDecoder(boolean isClient, HashMap sessionTable, SecretKey authKey, int macLength, ViewManager manager, ReentrantReadWriteLock rl, int signatureLength, boolean useMAC){
         this.isClient = isClient;
         this.sessionTable = sessionTable;
         this.authKey = authKey;

src/navigators/smart/communication/client/netty/NettyTOMMessageEncoder.java

@@ -20,7 +20,7 @@ package navigators.smart.communication.client.netty;
 
 import static org.jboss.netty.buffer.ChannelBuffers.buffer;
 
-import java.util.Hashtable;
+import java.util.HashMap;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import javax.crypto.Mac;
@@ -39,13 +39,13 @@ import org.jboss.netty.channel.SimpleChannelHandler;
 public class NettyTOMMessageEncoder extends SimpleChannelHandler {
     
     private boolean isClient;
-    private Hashtable sessionTable;
+    private HashMap sessionTable;
     private int macLength;
     private int signatureLength;
     private ReentrantReadWriteLock rl;
     private boolean useMAC;
 
-    public NettyTOMMessageEncoder(boolean isClient, Hashtable sessionTable, int macLength, ReentrantReadWriteLock rl, int signatureLength, boolean useMAC){
+    public NettyTOMMessageEncoder(boolean isClient, HashMap sessionTable, int macLength, ReentrantReadWriteLock rl, int signatureLength, boolean useMAC){
         this.isClient = isClient;
         this.sessionTable = sessionTable;
         this.macLength = macLength;