public static Operator getID(int id) {
            for (Operator operator : Operator.values()) {
                if (operator.id == id) {
                    return operator;
                }
            }
            return null;
        }
Returns the operator with the specified ID.

@param id the ID to search for
@return the Operator with the specified ID, or null if it does not exist.
document/src/main/java/com/yahoo/document/update/ArithmeticValueUpdate.java