content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.cassandra.io.tries;
  
  /**
   * An abstraction of a node given to the trie serializer to write.
   */
  public interface SerializationNode<VALUE>
  {
      /**
       * The number of children of the node.
       */
      int childCount();
  
      /**
       * The payload of the node if the node has any associated, otherwise null.
       */
      VALUE payload();
  
      /**
       * The transition character for the child at position i. Must be an integer between 0 and 255.
       */
      int transition(int i);
  
      /**
       * Returns the distance between this node's position and the child at index i.
       * Given as a difference calculation to be able to handle two different types of calls:
       * - writing nodes where all children's positions are already completely determined
       * - sizing and writing branches within a page where we don't know where we'll actually place
       *   the nodes, but we know how far backward the child nodes will end up
       */
      long serializedPositionDelta(int i, long nodePosition);
  
      /**
       * Returns the furthest distance that needs to be written to store this node, i.e.
       *   min(serializedPositionDelta(i, nodePosition) for 0 <= i < childCount())
       * Given separately as the loop above can be inefficient (e.g. when children are not yet written).
       */
      long maxPositionDelta(long nodePosition);
  }
  