Migrate branch bug18061

Author: tonyg

src/com/rabbitmq/client/AlreadyClosedException.java

@@ -0,0 +1,12 @@
+package com.rabbitmq.client;
+
+/*
+ * Thrown when application tries to perform an action on connection/channel
+ * which was already closed
+ */
+public class AlreadyClosedException extends ShutdownSignalException {
+	public AlreadyClosedException(String s)
+	{
+		super(true, true, s);
+	}
+}

src/com/rabbitmq/client/Channel.java

@@ -433,4 +433,38 @@ Queue.DeclareOk queueDeclare(int ticket, String queue, boolean passive, boolean
      * @throws java.io.IOException if an error is encountered
      */
     Tx.RollbackOk txRollback() throws IOException;
+
+    /**
+     * Add shutdown listener to the channel
+     * 
+     * @param listener {@link ShutdownListener} for the channel
+     */
+    void addShutdownListener(ShutdownListener listener);
+    
+    /**
+     * Remove shutdown listener for the channel.
+     * 
+     * @param listener {@link ShutdownListener} to be removed
+     */
+    void removeShutdownListener(ShutdownListener listener);
+    
+    /**
+     * Get connection channel shutdown reason.
+     * Return null if channel is still open.
+     * @see com.rabbitmq.client.ShutdownCause 
+     * @return shutdown reason if channel is closed
+     */
+    ShutdownSignalException getCloseReason();
+    
+    /**
+     * Determine if channel is currently open.
+     * Will return false if we are currently closing or closed.
+     * Checking this method should be only for information,
+     * because of the race conditions - state can change after the call.
+     * Instead just execute and and try to catch AlreadyClosedException
+     * 
+     * @see com.rabbitmq.client.impl.AMQChannel#isOpen()
+     * @return true when channel is open, false otherwise
+     */
+    boolean isOpen();
 }

src/com/rabbitmq/client/Connection.java

@@ -127,4 +127,40 @@ public interface Connection { // rename to AMQPConnection later, this is a tempo
      * @throws IOException if an I/O problem is encountered
      */
     void close(int closeCode, String closeMessage) throws IOException;
+    
+    /**
+     * Add connection shutdown listener.
+     * If the connection is already closed handler is fired immediately
+     * 
+     * @param listener {@link ShutdownListener} to the connection
+     */
+    void addShutdownListener(ShutdownListener listener);
+    
+    /**
+     * Remove shutdown listener for the connection.
+     * 
+     * @param listener {@link ShutdownListener} to be removed
+     */
+    void removeShutdownListener(ShutdownListener listener);
+    
+    /**
+     * Retrieve connection close reason.
+     * 
+     * @see com.rabbitmq.client.ShutdownCause
+     * @return information about the cause of closing the connection, or null if connection is still open
+     */
+    ShutdownSignalException getCloseReason();
+    
+    /**
+     * Determine whether the connection is currently open.
+     * Will return false if we are currently closing.
+     * Checking this method should be only for information,
+     * because of the race conditions - state can change after the call.
+     * Instead just execute and try to catch ShutdownSignalException
+     * and IOException
+     * 
+     * @see com.rabbitmq.client.impl.AMQConnection#isOpen()
+     * @return true when connection is open, false otherwise
+     */
+    boolean isOpen();
 }

src/com/rabbitmq/client/ShutdownListener.java

@@ -0,0 +1,9 @@
+package com.rabbitmq.client;
+
+import java.util.EventListener;
+
+public interface ShutdownListener extends EventListener {
+	
+	public void service(ShutdownSignalException cause);
+
+}

src/com/rabbitmq/client/ShutdownSignalException.java

@@ -28,7 +28,7 @@
  * Encapsulates a shutdown condition for a connection to an AMQP broker.
  */
 
-public class ShutdownSignalException extends Exception {
+public class ShutdownSignalException extends RuntimeException {
     /** True if the connection is shut down, or false if this signal refers to a channel */
     private final boolean _hardError;
 
@@ -59,11 +59,13 @@ public ShutdownSignalException(boolean hardError,
 
     /** @return true if this signals a connection error, or false if a channel error */
     public boolean isHardError() { return _hardError; }
+    
     /** @return true if this exception was caused by explicit application
      * action; false if it originated with the broker or as a result
      * of detectable non-deliberate application failure
      */
     public boolean isInitiatedByApplication() { return _initiatedByApplication; }
+    
     /** @return the reason object, if any */
     public Object getReason() { return _reason; }
 

src/com/rabbitmq/client/impl/AMQChannel.java

@@ -27,8 +27,10 @@
 
 import java.io.IOException;
 
+import com.rabbitmq.client.AlreadyClosedException;
 import com.rabbitmq.client.Command;
 import com.rabbitmq.client.Connection;
+import com.rabbitmq.client.ShutdownListener;
 import com.rabbitmq.client.ShutdownSignalException;
 import com.rabbitmq.utility.BlockingValueOrException;
 import com.rabbitmq.utility.SingleShotLinearTimer;
@@ -53,9 +55,9 @@ public abstract class AMQChannel {
 
     /** The current outstanding RPC request, if any. (Could become a queue in future.) */
     public RpcContinuation _activeRpc = null;
-
-    /** Indicates whether this channel is in a state to handle further activity. */
-    public volatile boolean _isOpen = true;
+    
+    /** Reason for closing the channel, null if still open */
+    public volatile ShutdownSignalException _cause;
 
     /**
      * Construct a channel on the given connection, with the given channel number.
@@ -117,6 +119,10 @@ public AMQCommand exnWrappingRpc(Method m)
     {
         try {
             return rpc(m);
+        } catch (AlreadyClosedException ace) {
+        	// Do not wrap it since it means that connection/channel
+        	// was closed in some action in the past
+        	throw ace;
         } catch (ShutdownSignalException ex) {
             throw wrap(ex);
         }
@@ -160,21 +166,36 @@ public synchronized void transmitAndEnqueue(Method m, RpcContinuation k)
         transmit(m);
     }
 
-    public synchronized RpcContinuation nextOutstandingRpc() {
+    public synchronized RpcContinuation nextOutstandingRpc()
+    {
         RpcContinuation result = _activeRpc;
         _activeRpc = null;
         return result;
     }
 
-    public boolean isOpen() {
-        return _isOpen;
+    /**
+     * Public API - Indicates whether this channel is in an open state
+     * @return true if channel is open, false otherwise
+     */
+    public boolean isOpen()
+    {
+        return _cause == null;
+    }
+    
+    /**
+     * Public API - Get the reason for closing the channel 
+     * @return object having information about the shutdown, or null if still open
+     */
+    public ShutdownSignalException getCloseReason() 
+    {
+    	return _cause;
     }
 
     public void ensureIsOpen()
-        throws IllegalStateException
+        throws AlreadyClosedException
     {
         if (!isOpen()) {
-            throw new IllegalStateException("Attempt to use closed channel");
+            throw new AlreadyClosedException("Attempt to use closed channel");
         }
     }
 
@@ -261,7 +282,7 @@ public void run() {
     public void processShutdownSignal(ShutdownSignalException signal) {
         synchronized (this) {
             ensureIsOpen(); // invariant: we should never be shut down more than once per instance
-            _isOpen = false;
+            _cause = signal;
         }
         RpcContinuation k = nextOutstandingRpc();
         if (k != null) {

src/com/rabbitmq/client/impl/AMQConnection.java

@@ -28,16 +28,20 @@
 import java.io.EOFException;
 import java.io.IOException;
 import java.net.SocketException;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
 import com.rabbitmq.client.AMQP;
 import com.rabbitmq.client.Address;
+import com.rabbitmq.client.AlreadyClosedException;
 import com.rabbitmq.client.Channel;
 import com.rabbitmq.client.Command;
 import com.rabbitmq.client.Connection;
 import com.rabbitmq.client.ConnectionParameters;
 import com.rabbitmq.client.MissedHeartbeatException;
 import com.rabbitmq.client.RedirectException;
+import com.rabbitmq.client.ShutdownListener;
 import com.rabbitmq.client.ShutdownSignalException;
 import com.rabbitmq.utility.Utility;
 
@@ -100,7 +104,11 @@ public class AMQConnection implements Connection {
 
     /** Handler for (otherwise-unhandled) exceptions that crop up in the mainloop. */
     public final ExceptionHandler _exceptionHandler;
-
+    
+    /** List of all shutdown listeners associated with the connection */
+    public List<ShutdownListener> listeners
+            = new ArrayList<ShutdownListener>();
+    
     /**
      * Protected API - respond, in the driver thread, to a ShutdownSignal.
      * @param channelNumber the number of the channel to disconnect
@@ -109,15 +117,19 @@ public final void disconnectChannel(int channelNumber) {
         _channelManager.disconnectChannel(channelNumber);
     }
 
+    /**
+     * Public API - Determine whether the connection is open
+     * @return true if haven't yet received shutdown signal, false otherwise
+     */
     public boolean isOpen() {
         return _shutdownCause == null;
     }
 
     public void ensureIsOpen()
-        throws IllegalStateException
+        throws AlreadyClosedException
     {
         if (!isOpen()) {
-            throw new IllegalStateException("Attempt to use closed connection");
+            throw new AlreadyClosedException("Attempt to use closed connection");
         }
     }
 
@@ -340,15 +352,13 @@ public Address[] open(final ConnectionParameters params, boolean insist)
             _frameHandler.setTimeout(HANDSHAKE_TIMEOUT);
             _frameHandler.sendHeader();
 
-            if (!isOpen()) {
-                // See bug 17389. The MainLoop could have shut down already in
-                // which case we don't want to wait forever for a reply.
-                
-                // There is no race if the MainLoop shuts down after enqueuing
-                // the RPC because if that happens the channel will correctly
-                // pass the exception into RPC, waking it up.
-                throw _shutdownCause;
-            }
+            // See bug 17389. The MainLoop could have shut down already in
+            // which case we don't want to wait forever for a reply.
+            
+            // There is no race if the MainLoop shuts down after enqueuing
+            // the RPC because if that happens the channel will correctly
+            // pass the exception into RPC, waking it up.
+            ensureIsOpen();
 
             AMQP.Connection.Start connStart =
                 (AMQP.Connection.Start) connStartBlocker.getReply().getMethod();
@@ -561,6 +571,7 @@ public void handleConnectionClose(Command closeCommand) {
             Utility.emptyStatement();
         }
         shutdown(closeCommand, false, null);
+        notifyListeners();
     }
 
     /**
@@ -616,6 +627,56 @@ public void close(int closeCode,
         } finally {
             _running = false;
         }
+        notifyListeners();
+    }
+    
+    /**
+     * Private API - notify the listeners attached to this connection
+     * @see com.rabbitmq.client.ShutdownListener
+     */
+    public void notifyListeners()
+    {
+        synchronized(listeners) {
+            for (ShutdownListener l: listeners)
+                l.service(getCloseReason());
+        }
+    }
+    
+    /**
+     * Public API - Add shutdown listener fired when closing the connection
+     * @see com.rabbitmq.client.Connection#addShutdownListener()
+     */
+    public void addShutdownListener(ShutdownListener listener)
+    {
+    	
+    	boolean closed = false;
+    	synchronized(listeners) {
+    		closed = !isOpen();
+    		listeners.add(listener);
+    	}
+    	if (closed)
+    		listener.service(_shutdownCause);	
+    }
+    
+    /**
+     * Public API - Remove shutdown listener for this connection
+     * Removing only the first found object
+     * @see com.rabbitmq.client.Connection#removeShutdownListener()
+     */   
+    public void removeShutdownListener(ShutdownListener listener)
+    {
+    	synchronized(listeners) {
+    		listeners.remove(listener);
+    	}
+    }
+    
+    /**
+     * Public API - Get reason for shutdown, or null if open
+     * @see com.rabbitmq.client.Connection#getShutdownReason()
+     */
+    public ShutdownSignalException getCloseReason()
+    {
+    	return _shutdownCause;
     }
 
     @Override public String toString() {