@Override
  public HCatEventMessage checkValid() {
    if (getTable() == null) throw new IllegalStateException("Table name unset.");
    if (getKeyValues() == null) throw new IllegalStateException("Partition values unset");
    return super.checkValid();
  }
HCat message sent when a table is Altered.
hcatalog/server-extensions/src/main/java/org/apache/hive/hcatalog/messaging/AlterPartitionMessage.java