public boolean addAll(StructSet ss) {
    boolean modified = false;
    if (!structType.equals(ss.structType)) {
      throw new IllegalArgumentException(
          "types do not match");
    }
    for (Iterator itr = ss.fieldValuesIterator(); itr.hasNext();) {
      Object[] vals = (Object[]) itr.next();
      if (contents.add(vals)) {
        modified = true;
      }
    }
    return modified;
  }
Remove the field values from a struct of the correct type
geode-core/src/main/java/org/apache/geode/cache/query/internal/StructSet.java