Displays error message when we try to change our nickname to an existing one in the chatroom.

resources/languages/resources.properties

@@ -99,6 +99,8 @@ service.gui.CHANGE_ROOM_SUBJECT_LABEL=In the field below, you can enter the new
 service.gui.CHANGE_NICK=Change nickname
 service.gui.CHANGE_NICKNAME=Change nickname...
 service.gui.CHANGE_NICKNAME_LABEL=In the field below, you can enter your new nickname.
+service.gui.CHANGE_NICKNAME_ERROR=Error Changing nickname
+service.gui.CHANGE_NICKNAME_CONFLICT_ERROR=Nickname already exist
 service.gui.CHANGE_VIDEO_QUALITY=Change remote video quality
 service.gui.CHAT_ROOM_ALREADY_JOINED=The {0} chat room is already joined.
 service.gui.CHAT_ROOM_CONFIGURATION={0} chat room configuration

src/net/java/sip/communicator/impl/gui/main/chat/ChatContactRightButtonMenu.java

@@ -362,9 +362,9 @@ else if (menuItemName.equals("changeNicknameItem"))
 
             if (result == MessageDialog.OK_RETURN_CODE)
             {
+                String nickname = reasonDialog.getReason().trim();
                 try
                 {
-                    String nickname = reasonDialog.getReason().trim();
                     room.setUserNickname(nickname);
                     ConfigurationUtils.updateChatRoomProperty(
                         room.getParentProvider(),
@@ -373,7 +373,24 @@ else if (menuItemName.equals("changeNicknameItem"))
                 }
                 catch (OperationFailedException ex)
                 {
-                    ex.printStackTrace();
+                    String errorMessage = null;
+                    if(ex.getErrorCode()
+                        == OperationFailedException.IDENTIFICATION_CONFLICT)
+                    {
+                        errorMessage = GuiActivator.getResources()
+                            .getI18NString(
+                                "service.gui.CHANGE_NICKNAME_CONFLICT_ERROR");
+                    }
+                    else
+                    {
+                        errorMessage = ex.getLocalizedMessage();
+                    }
+
+                    chatPanel.addErrorMessage(
+                        nickname,
+                        GuiActivator.getResources().getI18NString(
+                            "service.gui.CHANGE_NICKNAME_ERROR"),
+                        errorMessage);
                }
            }
         }

src/net/java/sip/communicator/impl/gui/main/chat/ChatConversationPanel.java

@@ -433,17 +433,8 @@ public String processMessage(   ChatMessage chatMessage,
         String chatString = "";
         String endHeaderTag = "";
 
-        String startSystemDivTag
-            = "<DIV id=\"systemMessage\" style=\"color:#627EB7;\">";
-        String endDivTag = "</DIV>";
-
         lastMessageUID = chatMessage.getMessageUID();
 
-        String startPlainTextTag
-            = ChatHtmlUtils.createStartPlainTextTag(contentType);
-        String endPlainTextTag
-            = ChatHtmlUtils.createEndPlainTextTag(contentType);
-
         if (messageType.equals(Chat.INCOMING_MESSAGE))
         {
             this.lastIncomingMsgTimestamp = new Date();
@@ -534,6 +525,14 @@ else if (messageType.equals(Chat.ACTION_MESSAGE))
         }
         else if (messageType.equals(Chat.SYSTEM_MESSAGE))
         {
+            String startSystemDivTag
+                = "<DIV id=\"systemMessage\" style=\"color:#627EB7;\">";
+            String endDivTag = "</DIV>";
+            String startPlainTextTag
+                = ChatHtmlUtils.createStartPlainTextTag(contentType);
+            String endPlainTextTag
+                = ChatHtmlUtils.createEndPlainTextTag(contentType);
+
             chatString
                 += startSystemDivTag + startPlainTextTag
                     + formatMessage(message, contentType, keyword)