private Set<String> calcExplicitModifiers() {
    Set<String> explicitModifiers = new HashSet<>();
    PsiModifierListStub stub = getGreenStub();
    if (stub != null) {
      int mask = stub.getModifiersMask();
      for (int i = 0; i < 31; i++) {
        int flag = 1 << i;
        if (BitUtil.isSet(mask, flag)) {
          ContainerUtil.addIfNotNull(explicitModifiers, ModifierFlags.MODIFIER_FLAG_TO_NAME_MAP.get(flag));
        }
      }
    } else {
      for (ASTNode child : getNode().getChildren(null)) {
        ContainerUtil.addIfNotNull(explicitModifiers, KEYWORD_TYPE_TO_NAME_MAP.get(child.getElementType()));
      }
    }

    return explicitModifiers;
  }
private Set<String> calcExplicitModifiers()