Assert.notNull(getName(), "Facet name can't be a null !!!");
Assert.isTrue(StringUtils.isNotBlank(field) && fields == null, "Please select field or fields on which to build the facets !!!");
StatisticalFacetBuilder builder = FacetBuilders.statisticalFacet(getName());
if (ArrayUtils.isNotEmpty(fields)) {
builder.fields(fields);
} else {
builder.field(field);
}
return builder;