bug fixed

Author: kousiknath

src/com/lld/chatapplication/README.md

@@ -2,7 +2,9 @@
 
 <b> Requirements </b>
 
-1. Users should be able to add other users to their uniqueUserContact list.
-2. Users should be able to create, join or invite other users.
+1. Users should be able to add / remove other users to / from their contact list.
+2. Users should be able to create, join groups.
 3. The application should support one-on-one and group chat.
+4. Private messages can be sent to a user if the receiver exists in the sender's contact list.
+5. Group messages can be sent by any group member to the whole group.
 4. No need to support features like encryption, media sharing etc.

src/com/lld/chatapplication/service/impl/ChatServiceImpl.java

@@ -38,6 +38,11 @@ public void sendGroupMessage(Group group, Message message) throws ServiceExcepti
             throw new ServiceException("sender, group and message should be non null");
         }
 
+        if (!group.getParticipants().contains(message.getSender())) {
+            throw new ServiceException("The sender " + message.getSender().getName()
+                    + " is not a member of the group: " + group.getName());
+        }
+
         this.conversationService.addMessage(group, message);
     }
 }