code: public boolean isAffiliationModification() {
          if (jid != null && affiliation != null) {
              assert (node == null && namespace == AffiliationNamespace.owner);
              return true;
          }
          return false;
      }
docs: Check if this is an affiliation element to modify affiliations on a node.
  
  @return <code>true</code> if this is an affiliation element to modify affiliations on a node, <code>false</code> otherwise.
  @since 4.2