Show message to the user when disconnected.

src/net/java/sip/communicator/impl/gui/main/i18n/Messages.java

@@ -33,7 +33,7 @@ public static String getString(String key, String param) {
 		try {
 			String sourceString = RESOURCE_BUNDLE.getString(key);
 			
-			return sourceString.replaceAll("?", param);
+			return sourceString.replaceAll("\\?", param);
 			
 		} catch (MissingResourceException e) {
 			

src/net/java/sip/communicator/impl/gui/main/i18n/messages.properties

@@ -14,6 +14,7 @@ close=Close
 configure=Configure
 connectionFailed=Connection failed
 connectionFailedMessage=The connection could not be established due to a network \n connection problem. Please check your network configuration.
+connectionExpiredMessage=You are currently disconnected from the ? server.
 contactPausedTyping=paused typing the message
 contactTyping=is typing a message
 contactTypingStateStale=typing state not updated
@@ -72,6 +73,7 @@ today=Today
 tools=Tools
 uin=UIN:
 unknown=Unknown user
+unregisteredMessage=You have been disconnected from the ? server. Please check your network connection.
 updateAutomatically=Automatically install new updates
 updates=Updates
 userInfo=User info

src/net/java/sip/communicator/impl/gui/main/login/LoginManager.java

@@ -176,10 +176,16 @@ else if(evt.getNewState()
         }
         else if(evt.getNewState()
                     .equals(RegistrationState.EXPIRED)){            
-            //TODO: Implement registration state changed to: EXPIRED
+            JOptionPane.showMessageDialog(null,                    
+                    Messages.getString("connectionExpiredMessage", protocolName), 
+                    Messages.getString("warning"),
+                    JOptionPane.WARNING_MESSAGE);
         }  
         else if(evt.getNewState().equals(RegistrationState.UNREGISTERED)){
-            //TODO: Implement registration state changed to UNREGISTERED
+            JOptionPane.showMessageDialog(null,                    
+                    Messages.getString("unregisteredMessage", protocolName), 
+                    Messages.getString("warning"),
+                    JOptionPane.WARNING_MESSAGE);
         }
     }