Get user role value from Enum

Question

I use this Enum for available user roles types:

public enum Role implements GrantedAuthority {
  ROLE_ADMIN, ROLE_CLIENT;

  public String getAuthority() {
    return name();
  }
}

Full code: Github

But when I try to convert the list using this code:

claims.put("auth", roles.stream()
                        .map(s -> new SimpleGrantedAuthority(s.getAuthority()))
                        .filter(Objects::nonNull)
                        .collect(Collectors.toList())
);

I always get NPE when I try to get s.getAuthority(). Do you know how I can fix this issue?

https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it — Reimeus, Jun 22 '20 at 23:01
First filter out nulls, then map values using non-nulls. In other words swap order of `map` and `filter`. — Pshemo, Jun 22 '20 at 23:03
Does this answer your question? [What is a NullPointerException, and how do I fix it?](https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Savior, Jun 22 '20 at 23:37

score 2 · Accepted Answer · answered Jun 22 '20 at 23:04

2

You should remove all the null values with filter before using map.

roles.stream().filter(Objects::nonNull)
              .map(s -> new SimpleGrantedAuthority(s.getAuthority()))
              .collect(Collectors.toList());

answered Jun 22 '20 at 23:04

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Get user role value from Enum

1 Answers1