replaced random printlns with strategically placed log statements, also added useful toString() for structs

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@582065 13f79535-47bb-0310-9956-ffa450edef68

16 files changed, 335 insertions, 63 deletions

diff --git a/java/common/src/main/java/org/apache/qpidity/transport/Channel.java b/java/common/src/main/java/org/apache/qpidity/transport/Channel.java
index b6b2ddbe7f..828d13d85a 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/Channel.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/Channel.java
@@ -20,11 +20,14 @@
  */
 package org.apache.qpidity.transport;
 
+import org.apache.qpidity.transport.util.Logger;
+
 import java.nio.ByteBuffer;
 
 import java.util.List;
 import java.util.ArrayList;
 
+
 import static org.apache.qpidity.transport.network.Frame.*;
 import static org.apache.qpidity.transport.util.Functions.*;
 
@@ -39,6 +42,8 @@ public class Channel extends Invoker
     implements Receiver<ProtocolEvent>, ProtocolDelegate<Void>
 {
 
+    private static final Logger log = Logger.get(Channel.class);
+
     final private Connection connection;
     final private int channel;
     final private MethodDelegate<Channel> delegate;
@@ -111,7 +116,7 @@ public class Channel extends Invoker
 
     public void closed()
     {
-        System.out.println("channel closed: " + this);
+        log.debug("channel closed: ", this);
         if (session != null)
         {
             session.closed();
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/ChannelDelegate.java b/java/common/src/main/java/org/apache/qpidity/transport/ChannelDelegate.java
index ec5cb74e5b..84621fbe25 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/ChannelDelegate.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/ChannelDelegate.java
@@ -37,21 +37,11 @@ class ChannelDelegate extends MethodDelegate<Channel>
         Session ssn = new Session();
         ssn.attach(channel);
         long lifetime = open.getDetachedLifetime();
-        System.out.println("Session Opened lifetime = " + lifetime);
         ssn.sessionAttached(UUID.randomUUID(), lifetime);
     }
 
-    public @Override void sessionAttached(Channel channel,
-                                          SessionAttached attached)
-    {
-        System.out.println("Session attached: " + attached.getSessionId() + ", " +
-                           attached.getDetachedLifetime());
-    }
-
     public @Override void sessionClosed(Channel channel, SessionClosed closed)
     {
-        System.out.println("Session closed: [" + closed.getReplyCode() + "]" +
-                           closed.getReplyText());
         channel.getSession().closed();
         // XXX: should we remove the channel from the connection? It
         // could have an external reference to it. Maybe we need a
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/Connection.java b/java/common/src/main/java/org/apache/qpidity/transport/Connection.java
index d29917afd5..c9299111a1 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/Connection.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/Connection.java
@@ -20,6 +20,8 @@
  */
 package org.apache.qpidity.transport;
 
+import org.apache.qpidity.transport.util.Logger;
+
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
@@ -42,6 +44,8 @@ public class Connection
     implements Receiver<ConnectionEvent>, Sender<ConnectionEvent>
 {
 
+    private static final Logger log = Logger.get(Connection.class);
+
     final private Sender<ConnectionEvent> sender;
     final private ConnectionDelegate delegate;
 
@@ -61,12 +65,14 @@ public class Connection
 
     public void received(ConnectionEvent event)
     {
+        log.debug("RECV: %s", event);
         Channel channel = getChannel(event.getChannel());
         channel.received(event.getProtocolEvent());
     }
 
     public void send(ConnectionEvent event)
     {
+        log.debug("SEND: %s", event);
         sender.send(event);
     }
 
@@ -94,7 +100,7 @@ public class Connection
 
     public void closed()
     {
-        System.out.println("connection closed: " + this);
+        log.debug("connection closed: %s", this);
         synchronized (channels)
         {
             for (Iterator<Channel> it = channels.values().iterator();
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/ConnectionDelegate.java b/java/common/src/main/java/org/apache/qpidity/transport/ConnectionDelegate.java
index 5c812042af..0d55dea7bd 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/ConnectionDelegate.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/ConnectionDelegate.java
@@ -20,6 +20,8 @@
  */
 package org.apache.qpidity.transport;
 
+import org.apache.qpidity.transport.util.Logger;
+
 import org.apache.qpidity.SecurityHelper;
 import org.apache.qpidity.QpidException;
 
@@ -49,6 +51,9 @@ import javax.security.sasl.SaslServer;
  */
 public abstract class ConnectionDelegate extends MethodDelegate<Channel>
 {
+
+    private static final Logger log = Logger.get(ConnectionDelegate.class);
+
     private String _username = "guest";
     private String _password = "guest";;
     private String _mechanism;
@@ -70,7 +75,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
 
     public void init(Channel ch, ProtocolHeader hdr)
     {
-        System.out.println(hdr);
         // XXX: hardcoded version
         if (hdr.getMajor() != 0 && hdr.getMinor() != 10)
         {
@@ -80,9 +84,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
         }
         else
         {
-
-            System.out.println("\n--------------------Broker Start Connection Negotiation -----------------------\n");
-
             ch.connectionStart(hdr.getMajor(), hdr.getMinor(), null, "PLAIN", "utf8");
         }
     }
@@ -92,9 +93,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
     //-----------------------------------------------
     @Override public void connectionStart(Channel context, ConnectionStart struct)
     {
-        System.out.println("\n--------------------Client Start Connection Negotiation -----------------------\n");
-        System.out.println("The broker has sent connection-start");
-
         String mechanism = null;
         String response = null;
         try
@@ -123,8 +121,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
 
     @Override public void connectionSecure(Channel context, ConnectionSecure struct)
     {
-        System.out.println("The broker has sent connection-secure with chanllenge " + struct.getChallenge());
-
         try
         {
             String response = new String(saslClient.evaluateChallenge(struct.getChallenge().getBytes()),_locale);
@@ -142,8 +138,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
 
     @Override public void connectionTune(Channel context, ConnectionTune struct)
     {
-        System.out.println("The broker has sent connection-tune " + struct.toString());
-
         // should update the channel max given by the broker.
         context.connectionTuneOk(struct.getChannelMax(), struct.getFrameMax(), struct.getHeartbeat());
         context.connectionOpen(_virtualHost, null, Option.INSIST);
@@ -153,8 +147,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
     @Override public void connectionOpenOk(Channel context, ConnectionOpenOk struct)
     {
         String knownHosts = struct.getKnownHosts();
-        System.out.println("The broker has opened the connection for use");
-        System.out.println("The broker supplied the following hosts for failover " + knownHosts);
         if(_negotiationCompleteLock != null)
         {
             _negotiationCompleteLock.lock();
@@ -167,7 +159,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
                 _negotiationCompleteLock.unlock();
             }
         }
-        System.out.println("\n-------------------- Client End Connection Negotiation -----------------------\n");
     }
 
     public void connectionRedirect(Channel context, ConnectionRedirect struct)
@@ -184,8 +175,6 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
         _locale = struct.getLocale();
         _mechanism = struct.getMechanism();
 
-        System.out.println("The client has sent connection-start-ok");
-
         //try
         //{
             //saslServer = Sasl.createSaslServer(_mechanism, "AMQP", "ABC",null,SecurityHelper.createCallbackHandler(_mechanism,_username,_password));
@@ -193,12 +182,10 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
             byte[] challenge = null;
             if ( challenge == null)
             {
-                System.out.println("Authentication sucessfull");
                 context.connectionTune(Integer.MAX_VALUE,maxFrame, 0);
             }
             else
             {
-                System.out.println("Authentication failed");
                 try
                 {
                     context.connectionSecure(new String(challenge,_locale));
@@ -221,26 +208,18 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
         }*/
     }
 
-    @Override public void connectionTuneOk(Channel context, ConnectionTuneOk struct)
-    {
-        System.out.println("The client has excepted the tune params");
-    }
-
     @Override public void connectionSecureOk(Channel context, ConnectionSecureOk struct)
     {
-        System.out.println("The client has sent connection-secure-ok");
         try
         {
             saslServer = Sasl.createSaslServer(_mechanism, "AMQP", "ABC",new HashMap(),SecurityHelper.createCallbackHandler(_mechanism,_username,_password));
             byte[] challenge = saslServer.evaluateResponse(struct.getResponse().getBytes());
             if ( challenge == null)
             {
-                System.out.println("Authentication sucessfull");
                 context.connectionTune(Integer.MAX_VALUE,maxFrame, 0);
             }
             else
             {
-                System.out.println("Authentication failed");
                 try
                 {
                     context.connectionSecure(new String(challenge,_locale));
@@ -267,9 +246,7 @@ public abstract class ConnectionDelegate extends MethodDelegate<Channel>
     @Override public void connectionOpen(Channel context, ConnectionOpen struct)
     {
        String hosts = "amqp:1223243232325";
-       System.out.println("The client has sent connection-open");
        context.connectionOpenOk(hosts);
-       System.out.println("\n-------------------- Broker End Connection Negotiation -----------------------\n");
     }
 
     public String getPassword()
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/ConnectionEvent.java b/java/common/src/main/java/org/apache/qpidity/transport/ConnectionEvent.java
index 6ed0df57a7..62d8f4d99d 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/ConnectionEvent.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/ConnectionEvent.java
@@ -48,4 +48,9 @@ public class ConnectionEvent
         return event;
     }
 
+    public String toString()
+    {
+        return String.format("[%d] %s", channel, event);
+    }
+
 }
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/Data.java b/java/common/src/main/java/org/apache/qpidity/transport/Data.java
index 72029d106e..602a7fbca1 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/Data.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/Data.java
@@ -26,6 +26,8 @@ import java.nio.ByteBuffer;
 
 import java.util.Collections;
 
+import static org.apache.qpidity.transport.util.Functions.*;
+
 
 /**
  * Data
@@ -76,4 +78,26 @@ public class Data implements ProtocolEvent
         delegate.data(context, this);
     }
 
+    public String toString()
+    {
+        StringBuffer str = new StringBuffer();
+        str.append("Data(");
+        boolean first = true;
+        for (ByteBuffer buf : getFragments())
+        {
+            if (first)
+            {
+                first = false;
+            }
+            else
+            {
+                str.append(" | ");
+            }
+            str.append(str(buf, 20));
+        }
+        str.setLength(str.length() - 3);
+        str.append(")");
+        return str.toString();
+    }
+
 }
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/Field.java b/java/common/src/main/java/org/apache/qpidity/transport/Field.java
new file mode 100644
index 0000000000..8c16b60779
--- /dev/null
+++ b/java/common/src/main/java/org/apache/qpidity/transport/Field.java
@@ -0,0 +1,72 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.qpidity.transport;
+
+import org.apache.qpidity.transport.codec.Decoder;
+import org.apache.qpidity.transport.codec.Encoder;
+
+
+/**
+ * Field
+ *
+ */
+
+public abstract class Field<T>
+{
+
+    private final Class<T> container;
+    private final String name;
+    private final int index;
+
+    Field(Class<T> container, String name, int index)
+    {
+        this.container = container;
+        this.name = name;
+        this.index = index;
+    }
+
+    public Class<T> getContainer()
+    {
+        return container;
+    }
+
+    public String getName()
+    {
+        return name;
+    }
+
+    public int getIndex()
+    {
+        return index;
+    }
+
+    protected T check(Object struct)
+    {
+        return container.cast(struct);
+    }
+
+    public abstract Object get(Object struct);
+
+    public abstract void read(Decoder dec, Object struct);
+
+    public abstract void write(Encoder enc, Object struct);
+
+}
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/Header.java b/java/common/src/main/java/org/apache/qpidity/transport/Header.java
index 6f3c7819f1..2384505cc4 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/Header.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/Header.java
@@ -68,4 +68,25 @@ public class Header implements ProtocolEvent {
         delegate.header(context, this);
     }
 
+    public String toString()
+    {
+        StringBuffer str = new StringBuffer();
+        str.append("Header(");
+        boolean first = true;
+        for (Struct s : structs)
+        {
+            if (first)
+            {
+                first = false;
+            }
+            else
+            {
+                str.append(", ");
+            }
+            str.append(s);
+        }
+        str.append(")");
+        return str.toString();
+    }
+
 }
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/RangeSet.java b/java/common/src/main/java/org/apache/qpidity/transport/RangeSet.java
index dfaec3702c..97d4be0d2e 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/RangeSet.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/RangeSet.java
@@ -100,7 +100,23 @@ public class RangeSet implements Iterable<Range>
 
     public String toString()
     {
-        return ranges.toString();
+        StringBuffer str = new StringBuffer();
+        str.append("{");
+        boolean first = true;
+        for (Range range : ranges)
+        {
+            if (first)
+            {
+                first = false;
+            }
+            else
+            {
+                str.append(", ");
+            }
+            str.append(range);
+        }
+        str.append("}");
+        return str.toString();
     }
 
     public static final void main(String[] args)
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/Session.java b/java/common/src/main/java/org/apache/qpidity/transport/Session.java
index 5441ac8f23..06abe14278 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/Session.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/Session.java
@@ -20,8 +20,11 @@
  */
 package org.apache.qpidity.transport;
 
+
 import org.apache.qpidity.transport.network.Frame;
 
+import org.apache.qpidity.transport.util.Logger;
+
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -38,6 +41,8 @@ import java.util.Map;
 public class Session extends Invoker
 {
 
+    private static final Logger log = Logger.get(Session.class);
+
     // channel may be null
     Channel channel;
 
@@ -82,7 +87,6 @@ public class Session extends Invoker
 
     public void processed(Method command)
     {
-        System.out.printf("processed[%d]: %s\n", command.getId(), command.getClass());
         processed(command.getId());
     }
 
@@ -99,13 +103,15 @@ public class Session extends Invoker
 
     public void processed(Range range)
     {
+        log.debug("%s processed(%s)", this, range);
+
         boolean flush;
         synchronized (processed)
         {
             processed.add(range);
             flush = syncPoint != null && processed.includes(syncPoint);
         }
-        if (! flush)
+        if (!flush)
         {
             flushProcessed();
         }
@@ -118,7 +124,6 @@ public class Session extends Invoker
         RangeSet rest = new RangeSet();
         for (Range r: processed)
         {
-            System.out.println("Completed Range [" + r.getLower() + "," + r.getUpper() +"]" );
             if (first)
             {
                 first = false;
@@ -129,15 +134,14 @@ public class Session extends Invoker
                 rest.add(r);
             }
         }
-        System.out.println("Notifying peer with execution complete");
         executionComplete(mark, rest);
     }
 
     void syncPoint()
     {
-        System.out.println("===========Request received to sync==========================");
-
-        Range range = new Range(0, getCommandsIn() - 1);
+        long id = getCommandsIn() - 1;
+        log.debug("%s synced to %d", this, id);
+        Range range = new Range(0, id - 1);
         boolean flush;
         synchronized (processed)
         {
@@ -178,7 +182,7 @@ public class Session extends Invoker
 
             if (commands.isEmpty())
             {
-                System.out.println("\n All outstanding commands are completed !!!! \n");
+                log.debug("%s no outsanding commands", this);
                 commands.notifyAll();
             }
         }
@@ -196,7 +200,6 @@ public class Session extends Invoker
         {
             synchronized (commands)
             {
-                System.out.println("sent command " + m.getClass().getName() + " command Id" + commandsOut);
                 commands.put(commandsOut++, m);
             }
         }
@@ -240,7 +243,7 @@ public class Session extends Invoker
 
     public void sync()
     {
-        System.out.println("calling sync()");
+        log.debug("%s sync()", this);
         synchronized (commands)
         {
             if (!commands.isEmpty())
@@ -251,9 +254,8 @@ public class Session extends Invoker
             while (!closed && !commands.isEmpty())
             {
                 try {
-                    System.out.println("\n============sync() waiting for commmands to be completed ==============\n");
+                    log.debug("%s   waiting");
                     commands.wait();
-                    System.out.println("\n============sync() got notified=========================================\n");
                 }
                 catch (InterruptedException e)
                 {
@@ -352,7 +354,7 @@ public class Session extends Invoker
     public void close()
     {
         sessionClose();
-        channel.close();
+        // XXX: channel.close();
     }
 
     public void closed()
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/SessionDelegate.java b/java/common/src/main/java/org/apache/qpidity/transport/SessionDelegate.java
index af41312532..5e36a77a98 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/SessionDelegate.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/SessionDelegate.java
@@ -70,12 +70,10 @@ public abstract class SessionDelegate
         {
             for (Range range : ranges)
             {
-                System.out.println("completed command range: " + range.getLower() + " to " + range.getUpper());
                 ssn.complete(range.getLower(), range.getUpper());
             }
         }
         ssn.complete(excmp.getCumulativeExecutionMark());
-        System.out.println("outstanding commands: " + ssn.getOutstandingCommands());
     }
 
     @Override public void executionFlush(Session ssn, ExecutionFlush flush)
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/Struct.java b/java/common/src/main/java/org/apache/qpidity/transport/Struct.java
index a3a07e9ebe..185615fda4 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/Struct.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/Struct.java
@@ -20,6 +20,8 @@
  */
 package org.apache.qpidity.transport;
 
+import java.util.List;
+
 import org.apache.qpidity.transport.codec.Encodable;
 
 
@@ -37,6 +39,34 @@ public abstract class Struct implements Encodable
         return StructFactory.create(type);
     }
 
+    public abstract List<Field<?>> getFields();
+
     public abstract int getEncodedType();
 
+    public String toString()
+    {
+        StringBuilder str = new StringBuilder();
+        str.append(getClass().getSimpleName());
+
+        str.append("(");
+        boolean first = true;
+        for (Field<?> f : getFields())
+        {
+            if (first)
+            {
+                first = false;
+            }
+            else
+            {
+                str.append(", ");
+            }
+            str.append(f.getName());
+            str.append("=");
+            str.append(f.get(this));
+        }
+        str.append(")");
+
+        return str.toString();
+    }
+
 }
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractDecoder.java b/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractDecoder.java
index 25151c5bcf..2855986f90 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractDecoder.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractDecoder.java
@@ -325,9 +325,7 @@ abstract class AbstractDecoder implements Decoder
             return readLonglong();
 
         case DOUBLE:
-            long bits = readLonglong();
-            System.out.println("double in: " + bits);
-            return Double.longBitsToDouble(bits);
+            return Double.longBitsToDouble(readLonglong());
 
         case SIXTEEN_OCTETS:
         case THIRTY_TWO_OCTETS:
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractEncoder.java b/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractEncoder.java
index 3d62393640..8e68a0f2b6 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractEncoder.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/codec/AbstractEncoder.java
@@ -496,7 +496,6 @@ abstract class AbstractEncoder implements Encoder
 
         case DOUBLE:
             long bits = Double.doubleToLongBits(coerce(Double.class, value));
-            System.out.println("double out: " + bits);
             writeLonglong(bits);
             break;
 
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/network/mina/MinaHandler.java b/java/common/src/main/java/org/apache/qpidity/transport/network/mina/MinaHandler.java
index 162e829c6f..02f1c7817f 100644
--- a/java/common/src/main/java/org/apache/qpidity/transport/network/mina/MinaHandler.java
+++ b/java/common/src/main/java/org/apache/qpidity/transport/network/mina/MinaHandler.java
@@ -40,6 +40,8 @@ import org.apache.qpidity.transport.ConnectionDelegate;
 import org.apache.qpidity.transport.Receiver;
 import org.apache.qpidity.transport.Sender;
 
+import org.apache.qpidity.transport.util.Logger;
+
 import org.apache.qpidity.transport.network.Assembler;
 import org.apache.qpidity.transport.network.Disassembler;
 import org.apache.qpidity.transport.network.InputHandler;
@@ -55,6 +57,8 @@ import org.apache.qpidity.transport.network.OutputHandler;
 public class MinaHandler implements IoHandler
 {
 
+    private static final Logger log = Logger.get(MinaHandler.class);
+
     private final ConnectionDelegate delegate;
     private final InputHandler.State state;
 
@@ -78,7 +82,7 @@ public class MinaHandler implements IoHandler
 
     public void exceptionCaught(IoSession ssn, Throwable e)
     {
-        e.printStackTrace();
+        log.error(e, "exception caught");
     }
 
     public void sessionCreated(final IoSession ssn)
@@ -88,7 +92,7 @@ public class MinaHandler implements IoHandler
 
     public void sessionOpened(final IoSession ssn)
     {
-        System.out.println("opened " + ssn);
+        log.debug("opened: %s", this);
         // XXX: hardcoded version + max-frame
         Connection conn = new Connection
             (new Disassembler(new OutputHandler(new MinaSender(ssn)),
@@ -107,7 +111,7 @@ public class MinaHandler implements IoHandler
 
     public void sessionClosed(IoSession ssn)
     {
-        System.out.println("closed " + ssn);
+        log.debug("closed: %s", ssn);
         Attachment attachment = (Attachment) ssn.getAttachment();
         attachment.receiver.closed();
         ssn.setAttachment(null);
diff --git a/java/common/src/main/java/org/apache/qpidity/transport/util/Logger.java b/java/common/src/main/java/org/apache/qpidity/transport/util/Logger.java
new file mode 100644
index 0000000000..0159036a34
--- /dev/null
+++ b/java/common/src/main/java/org/apache/qpidity/transport/util/Logger.java
@@ -0,0 +1,125 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.qpidity.transport.util;
+
+import org.slf4j.LoggerFactory;
+
+/**
+ * Logger
+ *
+ */
+
+public final class Logger
+{
+
+    public static final Logger get(Class<?> klass)
+    {
+        return new Logger(LoggerFactory.getLogger(klass));
+    }
+
+    private final org.slf4j.Logger log;
+
+    private Logger(org.slf4j.Logger log)
+    {
+        this.log = log;
+    }
+
+    public void debug(String message, Object ... args)
+    {
+        if (log.isDebugEnabled())
+        {
+            log.debug(String.format(message, args));
+        }
+    }
+
+    public void debug(Throwable t, String message, Object ... args)
+    {
+        if (log.isDebugEnabled())
+        {
+            log.debug(String.format(message, args), t);
+        }
+    }
+
+    public void error(String message, Object ... args)
+    {
+        if (log.isErrorEnabled())
+        {
+            log.error(String.format(message, args));
+        }
+    }
+
+    public void error(Throwable t, String message, Object ... args)
+    {
+        if (log.isErrorEnabled())
+        {
+            log.error(String.format(message, args), t);
+        }
+    }
+
+    public void warn(String message, Object ... args)
+    {
+        if (log.isWarnEnabled())
+        {
+            log.warn(String.format(message, args));
+        }
+    }
+
+    public void warn(Throwable t, String message, Object ... args)
+    {
+        if (log.isWarnEnabled())
+        {
+            log.warn(String.format(message, args), t);
+        }
+    }
+
+    public void info(String message, Object ... args)
+    {
+        if (log.isInfoEnabled())
+        {
+            log.info(String.format(message, args));
+        }
+    }
+
+    public void info(Throwable t, String message, Object ... args)
+    {
+        if (log.isInfoEnabled())
+        {
+            log.info(String.format(message, args), t);
+        }
+    }
+
+    public void trace(String message, Object ... args)
+    {
+        if (log.isTraceEnabled())
+        {
+            log.trace(String.format(message, args));
+        }
+    }
+
+    public void trace(Throwable t, String message, Object ... args)
+    {
+        if (log.isTraceEnabled())
+        {
+            log.trace(String.format(message, args), t);
+        }
+    }
+
+}