Target with modeled PublicIdentifier

PublicIdentifier.java

public class PublicIdentifier {

    private static final Pattern ALLOWED_REGEX = Pattern.compile("[a-zA-Z\\-_]*");

    private String value;

    public PublicIdentifier(String value) {
        validate(value);
        this.value = value;
    }

    private void validate(String value) {
        if(value == null || value.trim().isEmpty()) {
            throw new IllegalArgumentException("Public identifier should not be empty.");
        }
        if(!ALLOWED_REGEX.matcher(value).matches()) {
            throw new IllegalArgumentException("Public identifier should only contains valid characters.");
        }
    }
}

Target.java

public class Target {

    private Code code;
    private Name name;
    private PublicIdentifier publicIdentifier;

    public Target(Code code, Name name, PublicIdentifier publicIdentifier) {
        this.code = code;
        this.name = name;
        this.publicIdentifier = publicIdentifier;
    }
}