Adding HubConnection State Enum (#2627)

clients/java/signalr/src/main/java/HubConnection.java

@@ -15,8 +15,7 @@ public class HubConnection {
     private CallbackMap handlers = new CallbackMap();
     private HubProtocol protocol;
     private Gson gson = new Gson();
-
+    private HubConnectionState connectionState = HubConnectionState.DISCONNECTED;
-    public Boolean connected = false;
 
     public HubConnection(String url, Transport transport){
         this.url = url;
@@ -68,15 +67,19 @@ public class HubConnection {
         this(url, null);
     }
 
+    public HubConnectionState getConnectionState() {
+        return connectionState;
+    }
+
     public void start() throws InterruptedException {
         transport.setOnReceive(this.callback);
         transport.start();
-        connected = true;
+        connectionState = HubConnectionState.CONNECTED;
     }
 
     public void stop(){
         transport.stop();
-        connected = false;
+        connectionState = HubConnectionState.DISCONNECTED;
     }
 
     public void send(String method, Object... args) throws Exception {

clients/java/signalr/src/main/java/HubConnectionState.java

@@ -0,0 +1,7 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+public enum HubConnectionState {
+    CONNECTED,
+    DISCONNECTED,
+}

clients/java/signalr/src/test/java/HubConnectionTest.java

@@ -13,10 +13,10 @@ public class HubConnectionTest {
         Transport mockTransport = new MockEchoTransport();
         HubConnection hubConnection = new HubConnection("http://example.com", mockTransport);
         hubConnection.start();
-        assertTrue(hubConnection.connected);
+        assertEquals(HubConnectionState.CONNECTED, hubConnection.getConnectionState());
 
         hubConnection.stop();
-        assertFalse(hubConnection.connected);
+        assertEquals(HubConnectionState.DISCONNECTED, hubConnection.getConnectionState());
     }
 
     @Test