private boolean rebase(
     HttpServletRequest request,
     HttpServletResponse response,
     Repository db,
     String commitToRebase,
     String rebaseOperation)
     throws ServletException, JSONException, AmbiguousObjectException, IOException {
   JSONObject result = new JSONObject();
   try {
     Git git = new Git(db);
     RebaseCommand rebase = git.rebase();
     Operation operation;
     if (rebaseOperation != null) {
       operation = Operation.valueOf(rebaseOperation);
     } else {
       operation = Operation.BEGIN;
     }
     if (commitToRebase != null && !commitToRebase.isEmpty()) {
       ObjectId objectId = db.resolve(commitToRebase);
       rebase.setUpstream(objectId);
     } else if (operation.equals(Operation.BEGIN)) {
       return statusHandler.handleRequest(
           request,
           response,
           new ServerStatus(
               IStatus.ERROR, HttpServletResponse.SC_BAD_REQUEST, "Missing commit refId.", null));
     }
     rebase.setOperation(operation);
     RebaseResult rebaseResult = rebase.call();
     result.put(GitConstants.KEY_RESULT, rebaseResult.getStatus().name());
   } catch (UnmergedPathsException e) {
     // this error should be handled by client, so return a proper status
     result.put(GitConstants.KEY_RESULT, AdditionalRebaseStatus.FAILED_UNMERGED_PATHS.name());
   } catch (WrongRepositoryStateException e) {
     // this error should be handled by client, so return a proper status
     result.put(
         GitConstants.KEY_RESULT, AdditionalRebaseStatus.FAILED_WRONG_REPOSITORY_STATE.name());
   } catch (IllegalArgumentException e) {
     return statusHandler.handleRequest(
         request,
         response,
         new ServerStatus(
             IStatus.ERROR, HttpServletResponse.SC_BAD_REQUEST, "Invalid rebase operation.", e));
   } catch (GitAPIException e) {
     // get cause and try to handle
     if (e.getCause() instanceof org.eclipse.jgit.errors.CheckoutConflictException) {
       // this error should be handled by client, so return a proper status
       result.put(GitConstants.KEY_RESULT, AdditionalRebaseStatus.FAILED_PENDING_CHANGES.name());
     } else {
       return statusHandler.handleRequest(
           request,
           response,
           new ServerStatus(
               IStatus.ERROR,
               HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
               "An error occured when rebasing.",
               e));
     }
   }
   OrionServlet.writeJSONResponse(
       request, response, result, JsonURIUnqualificationStrategy.ALL_NO_GIT);
   return true;
 }