Added second session getter which fails if there is not session. Added...

Added second session getter which fails if there is not session. Added exception handling for those cases to the three controllers.

frontend/src/main/java/de/thm/spring/backend/Sessions.java

@@ -64,6 +64,18 @@ public final class Sessions {
         return sessions.get(key);
     }
 
+     /**
+     * Returns session by given http session key
+     *
+     * @param key - http session key
+     * @return Session from session list. If not session exists throws an exception
+     */
+    public Session getSessionOrError(String key) throws Exception {
+        if (!sessions.containsKey(key))
+            throw new Exception("No session for that key available");
+        return sessions.get(key);
+    }
+
     /**
      * Returns session by given http session key
      *

frontend/src/main/java/de/thm/spring/controller/DataController.java

@@ -57,15 +57,22 @@ public class DataController {
     @RequestMapping(value = "/data/{hg}", method = RequestMethod.GET)
     public String data(@PathVariable("hg") String assem, Model model, HttpSession httpSession) {
 
-        Sessions sessionsControll = Sessions.getInstance();
-        Session currentSession = sessionsControll.getSession(httpSession.getId());
 
+        Session currentSession;
         Genome.Assembly assembly;
         try {
+
+            Sessions sessionsControll = Sessions.getInstance();
+            currentSession = sessionsControll.getSessionOrError(httpSession.getId());
+
             assembly = Genome.Assembly.valueOf(assem);
         } catch (IllegalArgumentException e) {
             model.addAttribute("errorMessage", "There are no tracks with the genome version " + assem + ". Try www.enhort.mni.thm.de/data/hg19");
             return "error";
+        } catch (Exception e) {
+            logger.error("Exception {}", e.getMessage(), e);
+            model.addAttribute("errorMessage", "The calculation could not be saved, please run it again");
+            return "error";
         }
 
         BackendCommand command = //new BackendCommand(assembly, Command.Task.GET_TRACKS);

frontend/src/main/java/de/thm/spring/controller/ExportController.java

@@ -50,7 +50,14 @@ public class ExportController {
     @RequestMapping(value = "/export/csv", method = RequestMethod.GET)
     @ResponseBody
     public FileSystemResource downloadCSV(HttpSession httpSession) {
-        Session currentSession = Sessions.getInstance().getSession(httpSession.getId());
+
+        Session currentSession = null;
+        try {
+            currentSession = Sessions.getInstance().getSessionOrError(httpSession.getId());
+        } catch (Exception e) {
+            logger.error("Exception {}", e.getMessage(), e);
+            //TODO show error message, there is no data to download
+        }
 
         //create file
         File output = new File("/tmp/csv_output_" + httpSession.getId());

frontend/src/main/java/de/thm/spring/controller/WizardController.java

@@ -77,7 +77,16 @@ public class WizardController {
     public String wizard_get(Model model, HttpSession httpSession, @ModelAttribute InterfaceCommand interfaceCommand) {
 
         Sessions sessionsControll = Sessions.getInstance();
-        Session currentSession = sessionsControll.getSession(httpSession.getId());
+        Session currentSession = null;
+
+        try {
+            currentSession = sessionsControll.getSessionOrError(httpSession.getId());
+        } catch (Exception e) {
+            logger.error("Exception {}", e.getMessage(), e);
+            model.addAttribute("errorMessage", "The calculation could not be saved, please run it again");
+            return "error";
+        }
+
 
         if(currentSession.getCollector() != null)
             interfaceCommand.setTracks(currentSession.getCollector().getTracks());