table.setMultiSelect(true);
table.setNullSelectionAllowed(true);
table.setSelectable(true);
CheckBox selectAllCheckbox = new CheckBox("Select All");
selectAllCheckbox.addValueChangeListener(new ValueChangeListener() {
@Override
public void valueChange(
com.vaadin.data.Property.ValueChangeEvent event) {
Object checked = event.getProperty().getValue();
if (checked instanceof Boolean) {