public interface HashTableInterface<T extends KeyedItem> {
  public void insert(T item) throws HashTableFullException;
  // PRE: item.getKey()!=0
  public T find(long key);
  // PRE: item.getKey()!=0
  // return null if the item with key 'key' was not found
  public T delete(long key);
  // PRE: item.getKey()!=0
  // return null if the item with key 'key' was not found
}