public void OnSelectHost() {
    MoveHost model = (MoveHost) getWindow();

    if (model.getProgress() != null) {
      return;
    }

    if (!model.Validate()) {
      return;
    }

    model.setSelectedHosts(new java.util.ArrayList<VDS>());
    for (EntityModel a : Linq.<EntityModel>Cast(model.getItems())) {
      if (a.getIsSelected()) {
        model.getSelectedHosts().add((VDS) a.getEntity());
      }
    }

    VDSGroup cluster = (VDSGroup) model.getCluster().getSelectedItem();

    java.util.ArrayList<VdcActionParametersBase> paramerterList =
        new java.util.ArrayList<VdcActionParametersBase>();
    for (VDS host : model.getSelectedHosts()) {
      // Try to change host's cluster as neccessary.
      if (host.getvds_group_id() != null && !host.getvds_group_id().equals(cluster.getId())) {
        paramerterList.add(new ChangeVDSClusterParameters(cluster.getId(), host.getId()));
      }
    }
    model.StartProgress(null);
    Frontend.RunMultipleAction(
        VdcActionType.ChangeVDSCluster,
        paramerterList,
        new IFrontendMultipleActionAsyncCallback() {
          @Override
          public void Executed(FrontendMultipleActionAsyncResult result) {

            ClusterGuideModel clusterGuideModel = (ClusterGuideModel) result.getState();
            java.util.ArrayList<VDS> hosts =
                ((MoveHost) clusterGuideModel.getWindow()).getSelectedHosts();
            java.util.ArrayList<VdcReturnValueBase> retVals =
                (java.util.ArrayList<VdcReturnValueBase>) result.getReturnValue();
            if (retVals != null && hosts.size() == retVals.size()) {
              int i = 0;
              for (VDS selectedHost : hosts) {
                if (selectedHost.getstatus() == VDSStatus.PendingApproval
                    && retVals.get(i) != null
                    && retVals.get(i).getSucceeded()) {
                  Frontend.RunAction(
                      VdcActionType.ApproveVds, new ApproveVdsParameters(selectedHost.getId()));
                }
              }
              i++;
            }
            clusterGuideModel.getWindow().StopProgress();
            clusterGuideModel.Cancel();
            clusterGuideModel.PostAction();
          }
        },
        this);
  }
  public boolean Validate() {
    getDescription().ValidateEntity(new IValidation[] {new NotEmptyValidation()});

    boolean isDisksValid = false;
    setMessage(null);
    if (getDisks() != null) {
      for (EntityModel a : getDisks()) {
        if (a.getIsSelected()) {
          isDisksValid = true;
          break;
        }
      }
      if (!isDisksValid) {
        setMessage("At least one disk must be marked.");
        return false;
      }

      return getDescription().getIsValid();
    }

    return getDescription().getIsValid();
  }