javadev / pt-backend

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import org.springframework.stereotype.Component;

import org.springframework.validation.Errors;

import org.springframework.validation.Validator;

class CertificateValidator implements Validator {

    private static final Pattern CERTIFICATE_PATTERN = Pattern.compile("^[A-Z]{4}[0-9]{4}$");

    @Override

    public void validate(final Object obj, final Errors errors) {

        final String certificate = (String) obj;

        if (certificate == null || certificate.trim().isEmpty()) {

            errors.reject("certificate", "Invalid empty certificate");

            return;

        }

        final Matcher matcher = CERTIFICATE_PATTERN.matcher(certificate);

        if (!matcher.matches()) {

            errors.reject("certificate", "Invalid certificate code (" + certificate + ")");

        }

    }

}