Issue #251 - Fix Warning "event of type UNKNOWN not handled"

sources/src/main/java/com/ullink/slack/simpleslackapi/events/EventType.java

@@ -22,6 +22,7 @@ public enum EventType
     PIN_ADDED("pin_added"),
     PIN_REMOVED("pin_removed"),
     USER_TYPING("user_typing"),
+    HELLO("hello"),
     OTHER("-");
 
     private static final Map<String, EventType> CODE_MAP = new HashMap<>();

sources/src/main/java/com/ullink/slack/simpleslackapi/events/Hello.java

@@ -0,0 +1,8 @@
+package com.ullink.slack.simpleslackapi.events;
+
+public class Hello implements SlackEvent {
+    @Override
+    public SlackEventType getEventType() {
+        return SlackEventType.HELLO;
+    }
+}

sources/src/main/java/com/ullink/slack/simpleslackapi/events/SlackEventType.java

@@ -23,5 +23,6 @@ public enum SlackEventType {
     PIN_REMOVED,
     USER_TYPING,
     UNKNOWN,
-    SLACK_DISCONNECTED;
+    SLACK_DISCONNECTED,
+    HELLO
 }

sources/src/main/java/com/ullink/slack/simpleslackapi/impl/SlackJSONMessageParser.java

@@ -18,7 +18,7 @@
 class SlackJSONMessageParser {
     private static final Logger LOGGER                     = LoggerFactory.getLogger(SlackJSONMessageParser.class);
 
-    public static enum SlackMessageSubType
+    public enum SlackMessageSubType
     {
         CHANNEL_JOIN("channel_join"), CHANNEL_LEAVE("channel_leave"), MESSAGE_CHANGED("message_changed"), MESSAGE_DELETED("message_deleted"), OTHER("-"), FILE_SHARE("file_share"), MESSAGE_REPLIED("message_replied");
 
@@ -96,6 +96,8 @@ static SlackEvent decode(SlackSession slackSession, JsonObject obj) {
                 return extractPinRemovedEvent(slackSession, obj);
             case USER_TYPING:
                 return extractUserTypingEvent(slackSession, obj);
+            case HELLO:
+                return new Hello();
             default:
                 return new UnknownEvent(obj.toString());
         }

sources/src/main/java/com/ullink/slack/simpleslackapi/impl/SlackWebSocketSessionImpl.java

@@ -235,6 +235,9 @@ void dispatch(SlackEvent event) {
                 case USER_TYPING:
                     dispatchImpl((UserTyping) event, userTypingListener);
                     break;
+                case HELLO:
+                    // don't need to dispatch this
+                    break;
                 default:
                     LOGGER.warn("event of type " + event.getEventType() + " not handled: " + ((UnknownEvent)event).getJsonPayload());
             }