Don't try to log in twice

src/main/java/ctbrec/sites/cam4/Cam4.java

@@ -66,7 +66,10 @@ public class Cam4 extends AbstractSite {
 
     @Override
     public Integer getTokenBalance() throws IOException {
-        return 0;
+        if (!credentialsAvailable()) {
+            throw new IOException("Not logged in");
+        }
+        return ((Cam4HttpClient)getHttpClient()).getTokenBalance();
     }
 
     @Override

src/main/java/ctbrec/sites/cam4/Cam4HttpClient.java

@@ -24,7 +24,11 @@ public class Cam4HttpClient extends HttpClient {
     private static final transient Logger LOG = LoggerFactory.getLogger(Cam4HttpClient.class);
 
     @Override
-    public boolean login() throws IOException {
+    public synchronized boolean login() throws IOException {
+        if(loggedIn) {
+            return true;
+        }
+
         BlockingQueue<Boolean> queue = new LinkedBlockingQueue<>();
 
         Runnable showDialog = () -> {
@@ -94,4 +98,12 @@ public class Cam4HttpClient extends HttpClient {
         }
         cookieJar.saveFromResponse(origUrl, cookies);
     }
+
+    protected int getTokenBalance() throws IOException {
+        if(!loggedIn) {
+            login();
+        }
+
+        throw new RuntimeException("Not implemented, yet");
+    }
 }

src/main/java/ctbrec/sites/cam4/Cam4Model.java

@@ -124,14 +124,13 @@ public class Cam4Model extends AbstractModel {
 
     @Override
     public void invalidateCacheEntries() {
-        // TODO Auto-generated method stub
-
+        resolution = null;
+        playlistUrl = null;
     }
 
     @Override
     public void receiveTip(int tokens) throws IOException {
-        // TODO Auto-generated method stub
-
+        throw new RuntimeException("Not implemented for Cam4, yet");
     }
 
     @Override