public static Bson ascending(final List<String> fieldNames) {
        notNull("fieldNames", fieldNames);
        return compoundIndex(fieldNames, new BsonInt32(1));
    }
public static Bson ascending(final List<String> fieldNames) {
        notNull("fieldNames", fieldNames);
        return compoundIndex(fieldNames, new BsonInt32(1));
    }
public static Bson ascending ( final List < String > fieldNames ) { notNull ( "fieldNames" , fieldNames ) ; return compoundIndex ( fieldNames , new BsonInt32 ( 1 ) ) ; }
Create an index key for an ascending index on the given fields.

@param fieldNames the field names, which must contain at least one
@return the index specification
@mongodb.driver.manual core/indexes indexes
Create an index key for an ascending index on the given fields .