/*
 * 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.geode.internal.cache.persistence.query;

import org.apache.geode.internal.cache.CachedDeserializable;

/**
 * The contract for a sorted bag of temporary results for a query. This bag may be persisted on
 * disk.
 * 
 * This class is threadsafe. Iterators will reflect all entries added to the set up until the time
 * that the iterator was obtained. After that they may or may not reflect modifications to the set
 * while the iteration is in progress. They will guarantee that entries will be returned in the
 * correct order.
 * 
 * The element is allowed to be an object, or a CachedDeserializable.
 * 
 * If multiple instances of the same element are required, use SortedResultBag instead.
 * 
 * The result set should be closed using the close method to free up resources when it is no longer
 * in use.
 * 
 * @since GemFire cedar
 */
public interface ResultBag {

  /**
   * Add an element to the bag. Multiple copies of the same entry may be inserted into the bag.
   * 
   * @param e the element. e may be NULL.
   */
  void add(Object e);

  /**
   * Return all of the elements in the set.
   */
  CloseableIterator<CachedDeserializable> iterator();

  /**
   * Close the result set and free up any resources on disk associated with the result set.
   */
  public void close();
}
