code: public void setIgnoredUserNamePatterns(Collection<Pattern> ignoredUserNamePatterns) {
          if (ignoredUserNamePatterns == null) {
              this.ignoredUserNamePatterns = null;
          } else {
              this.ignoredUserNamePatterns = ImmutableSet.copyOf(ignoredUserNamePatterns);
          }
      }
docs: If no <code>ignoredUserNamePatterns</code> {@link Collection} is configured all user-names
  are supported otherwise exact regex pattern matching is done to determine ignored userNames.
  The property defaults to null (all user names)
  
  @param ignoredUserNamePatterns the ignoredUserNamePatterns to set