/*

  * Copyright 2007 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 1.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl1.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.student.common.ui.client.application;

 import org.kuali.student.common.ui.client.security.SessionTimeoutHandler;

 import org.kuali.student.common.ui.client.security.SpringSecurityLoginDialogHandler;

 import org.kuali.student.common.ui.client.service.exceptions.VersionMismatchClientException;

 import org.kuali.student.common.ui.client.widgets.KSErrorDialog;

 import com.google.gwt.core.client.GWT;

 import com.google.gwt.user.client.Window;

 import com.google.gwt.user.client.rpc.AsyncCallback;

 /**

  * This extends the AysncCallback to handle uncaught RPC exceptions and

  * handle authentication.

  * 

  * @author Kuali Student Team

  *

  */

 public abstract class KSAsyncCallback<T> implements AsyncCallback<T>{

         private static final SessionTimeoutHandler sessionTimeoutHandler = GWT.create(SpringSecurityLoginDialogHandler.class);

         /**

          * It is recommended that this method not be overrided, as it provides session timeout handling. 

          * Instead the handleFailure method should be overriden to handle rpc call error.

          *  

          */

         public void onFailure(Throwable caught) {  

             if (sessionTimeoutHandler.isSessionTimeout(caught)){

                 handleTimeout(caught);

                 sessionTimeoutHandler.handleSessionTimeout();

         } else if (caught instanceof VersionMismatchClientException){

             handleVersionMismatch(caught);

         }else {        

                 handleFailure(caught);

         }

     }

     /**

      * Override this method to process any exceptions you wish to handle. The default implementation displays 

      * an error dialog with the message and logs the exception.

      * 

      * @param caught

      */

     public void handleFailure(Throwable caught){

             if (!sessionTimeoutHandler.isSessionTimeout(caught)){

                     KSErrorDialog.show(caught);

             }

         GWT.log("Exception:", caught);

     }

     /**

      * By default this defers to handleFailure. Override this handle a rpc failure due to timeout differently

      * from other exceptions.

      * 

      * @param caught

      */

     public void handleTimeout(Throwable caught){

             handleFailure(caught);

     }

     public void handleVersionMismatch(Throwable caught){

         String message = null;

         if (caught.getMessage() != null){

             message = "Version Error: " + caught.getMessage() + "\n\n";

         }

         message += "This page has been updated by another user since you loaded it. Please refresh and re-apply changes before saving.";

         Window.alert(message);

     }

 }