class MergeController extends AbstractMantleController implements Consumer<DataGroupInfo> {

    private void checkAssociations()
    {
        if (!myIsCheckingAssociations)
        {
            myIsCheckingAssociations = true;
            try
            {
                List<Pair<String, List<String>>> layers = New.list();
                MantleToolbox mantleToolbox = MantleToolboxUtils.getMantleToolbox(myToolbox);
                for (DataTypeInfo layer : myModel.getLayers(mantleToolbox))
                {
                    layers.add(new Pair<>(layer.getTypeKey(), layer.getMetaDataInfo().getKeyNames()));
                }

                if (myMapper.getDefinedColumns(layers).isEmpty())
                {
                    myModel.getUserMessage().set("These layers have no associated columns.");
                }
                else
                {
                    myModel.getUserMessage().set("");
                }
            }
            finally
            {
                myIsCheckingAssociations = false;
            }
        }
    }

    public  MergeController(Toolbox toolbox, MergePrefs mergePreferences, Runnable saveCallback);

}