Mam problem z niezgodnością typów błędów przy używaniu Either.
Metoda tworząca encję Account:
static Either<AccountError,Account> create(
String userNameCandidate,
UserNameUniquenessValidator userNameUniquenessValidator,
String passwordCandidate,
PasswordEncoder passwordEncoder) {
return UserName
.create(userNameCandidate,userNameUniquenessValidator)
.flatMap(correctUserName -> Password
.create(passwordCandidate,passwordEncoder)
.map(correctPassword -> new Account(correctUserName,correctPassword)));
}
Value objecty UserName i Password:
@Embeddable
final class UserName implements Serializable {
public static final Integer MIN_USER_NAME_LENGTH = 3;
public static final Integer MAX_USER_NAME_LENGTH = 15;
@Column
private final String userName;
UserName(String userNam) {
this.userName = userNam;
}
//For JPA only.Don't use!
public UserName() {
this.userName = "default";
}
static Either<WrongUserNameFormatError,UserName> create(
String userNameCandidate,
UserNameUniquenessValidator userNameUniquenessValidator) {
if (userNameCandidate.isEmpty()) {
return Either.left(new WrongUserNameFormatError("Empty user name."));
}
var isUserNameCandidateLengthWrong =
userNameCandidate.length() < MIN_USER_NAME_LENGTH &&
userNameCandidate.length() > MAX_USER_NAME_LENGTH;
if (isUserNameCandidateLengthWrong) {
return Either.left(new WrongUserNameFormatError(
"Wrong user name length: " + userNameCandidate.length() +
".Min: " + MIN_USER_NAME_LENGTH +
".Max: " + MAX_USER_NAME_LENGTH));
}
if (!userNameUniquenessValidator.isUnique(userNameCandidate)) {
return Either.left(new WrongUserNameFormatError("Not unique user name: " + userNameCandidate));
}
return Either.right(new UserName(userNameCandidate));
}
public String getUserName() {
return userName;
}
}
@Embeddable
final class Password implements Serializable {
public static final Integer MIN_PASSWORD_LENGTH = 5;
@Column
private final String password;
private Password(String password) {
this.password = password;
}
//For JPA only.Don't use!
public Password() {
this.password = "default";
}
static Either<WrongPasswordFormatError,Password> create(String passwordCandidate, PasswordEncoder passwordEncoder) {
if (passwordCandidate.length() >= MIN_PASSWORD_LENGTH) {
var encodedPassword= passwordEncoder.encode(passwordCandidate);
return Either.right(new Password(encodedPassword));
}
else {
return Either.left(new WrongPasswordFormatError(
"Wrong password length: " + passwordCandidate.length() +
". Min: " + MIN_PASSWORD_LENGTH));
}
}
public String getPassword() {
return password;
}
}
Dostaje błędy: Required Either<AccountError,Account>, provided Either<WrongUserNameFormat, Object>, incompatible constraint: AccountError and WrongUserNameFormatError mimo, że wszystkie błędy dziedziczą po AccountError.
Java 
