// remove not-null constraints
for (HtmlInput<?> i : inputs)
i.setNillable(true);
// add the file input for csv
FileInput csvInput = new FileInput("__csvdata");
csvInput.setLabel("CSV file");
csvInput.setTooltip("choose here your data in comma-separated format.");
csvInput.setDescription("Select your CSV file here.");
inputs.add(csvInput);
return inputs;
}