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.db.tries;
  
  import java.util.AbstractMap;
  import java.util.Iterator;
  import java.util.Map;
  
  import org.apache.cassandra.utils.bytecomparable.ByteComparable;
  
  /**
   * Convertor of trie entries to iterator where each entry is passed through {@link #mapContent} (to be implemented by
   * descendants).
   */
  public abstract class TrieEntriesIterator<T, V> extends TriePathReconstructor implements Iterator<V>
  {
      private final Trie.Cursor<T> cursor;
      T next;
      boolean gotNext;
  
      protected TrieEntriesIterator(Trie<T> trie, Direction direction)
      {
          cursor = trie.cursor(direction);
          assert cursor.depth() == 0;
          next = cursor.content();
          gotNext = next != null;
      }
  
      public boolean hasNext()
      {
          if (!gotNext)
          {
              next = cursor.advanceToContent(this);
              gotNext = true;
          }
  
          return next != null;
      }
  
      public V next()
      {
          gotNext = false;
          T v = next;
          next = null;
          return mapContent(v, keyBytes, keyPos);
      }
  
      protected abstract V mapContent(T content, byte[] bytes, int byteLength);
  
      /**
       * Iterator representing the content of the trie a sequence of (path, content) pairs.
       */
      static class AsEntries<T> extends TrieEntriesIterator<T, Map.Entry<ByteComparable, T>>
      {
          public AsEntries(Trie<T> trie, Direction direction)
          {
              super(trie, direction);
          }
  
          @Override
          protected Map.Entry<ByteComparable, T> mapContent(T content, byte[] bytes, int byteLength)
          {
              return toEntry(content, bytes, byteLength);
          }
      }
  
      static <T> java.util.Map.Entry<ByteComparable, T> toEntry(T content, byte[] bytes, int byteLength)
      {
          return new AbstractMap.SimpleImmutableEntry<>(toByteComparable(bytes, byteLength), content);
      }
  }
  