US Phone Validation w/ext

ValidateUtil.java

package org.formium.util;

import com.google.i18n.phonenumbers.NumberParseException;
import com.google.i18n.phonenumbers.PhoneNumberUtil;
import com.google.i18n.phonenumbers.Phonenumber;

import java.util.Optional;

public class ValidateUtil {
    public static Optional<String> validatePhone(String phone) {
        if (phone == null) {
            return Optional.empty();
        }
        phone = phone.trim();
        if ("".equals(phone)) {
            return Optional.empty();
        }
        PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
        try {
            Phonenumber.PhoneNumber number = phoneUtil.parse(phone, "US");
            String ext = number.getExtension().length() > 0 ? ";ext=" + number.getExtension() : "";
            return Optional.of(phoneUtil.format(number, PhoneNumberUtil.PhoneNumberFormat.E164) + ext);
        } catch (NumberParseException e) {
            return Optional.empty();
        }
    }
}