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.index.sai.postings;
  
  import java.io.Closeable;
  import java.io.IOException;
  
  /**
   * Interface for advancing on and consuming a posting list.
   */
  public interface PostingList extends Closeable
  {
      PostingList EMPTY = new EmptyPostingList();
  
      long OFFSET_NOT_FOUND = -1;
      long END_OF_STREAM = Long.MAX_VALUE;
  
      @Override
      default void close() {}
  
      default long minimum()
      {
          return Long.MIN_VALUE;
      }
  
      default long maximum()
      {
          return Long.MAX_VALUE;
      }
  
      /**
       * Retrieves the next segment row ID, not including row IDs that have been returned by {@link #advance(long)}.
       *
       * @return next segment row ID
       */
      long nextPosting() throws IOException;
  
      /**
       * Returns the upper bound of postings in the list. During a merge individual postings may be
       * de-duplicated, so we can't return the exact size only the upper bound of the size.
       */
      long size();
  
      /**
       * Advances to the first row ID beyond the current that is greater than or equal to the
       * target, and returns that row ID. Exhausts the iterator and returns {@link #END_OF_STREAM} if
       * the target is greater than the highest row ID.
       * <p>
       * Note: Callers must use the return value of this method before calling {@link #nextPosting()}, as calling
       * that method will return the next posting, not the one to which we have just advanced.
       *
       * @param targetRowID target row ID to advance to
       *
       * @return first segment row ID which is >= the target row ID or {@link PostingList#END_OF_STREAM} if one does not exist
       */
      long advance(long targetRowID) throws IOException;
  
      class EmptyPostingList implements PostingList
      {
          @Override
          public long nextPosting() throws IOException
          {
              return END_OF_STREAM;
          }
  
          @Override
          public long size()
          {
              return 0;
          }
  
          @Override
          public long advance(long targetRowID) throws IOException
          {
              return END_OF_STREAM;
          }
      }
  }
  