added channel::usable() to replace channel::connected()

include/amqpcpp/channel.h

@@ -125,12 +125,23 @@ public:
     }
 
     /**
-     *  Is the channel connected?
+     *  Is the channel usable / not yet closed?
      *  @return bool
      */
-    bool connected()
+    bool usable() const
     {
-        return _implementation->connected();
+        return _implementation->usable();
+    }
+    
+    /**
+     *  Is the channel connected?
+     *  This method is deprecated: use Channel::usable()
+     *  @return bool
+     *  @deprecated
+     */
+    bool connected() const
+    {
+        return usable();
     }
 
     /**

include/amqpcpp/channelimpl.h

@@ -251,10 +251,10 @@ public:
     Deferred &resume();
 
     /**
-     *  Is the channel connected?
+     *  Is the channel usable / not yet closed?
      *  @return bool
      */
-    bool connected()
+    bool usable() const
     {
         return _state == state_connected || _state == state_ready;
     }

src/channelimpl.cpp

@@ -71,8 +71,8 @@ void ChannelImpl::onError(const ErrorCallback &callback)
     // store callback
     _errorCallback = callback;
 
-    // if the channel is connected, all is ok
-    if (connected()) return;
+    // if the channel is usable, all is ok
+    if (usable()) return;
     
     // is the channel closing down?
     if (_state == state_closing) return callback("Channel is closing down");
@@ -246,8 +246,8 @@ Deferred &ChannelImpl::rollbackTransaction()
  */
 Deferred &ChannelImpl::close()
 {
-    // this is completely pointless if not connected
-    if (!connected()) return push(std::make_shared<Deferred>(_state == state_closing));
+    // this is completely pointless if already closed
+    if (!usable()) return push(std::make_shared<Deferred>(_state == state_closing));
     
     // send a channel close frame
     auto &handler = push(ChannelCloseFrame(_id));