/*
 * 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.persistence.query.mock.ResultListImpl;
import org.apache.geode.internal.cache.persistence.query.mock.SortedResultBagImpl;
import org.apache.geode.internal.cache.persistence.query.mock.SortedResultSetImpl;

/**
 * This is a factory for temporary result sets that overflow to disk.
 * 
 * The result sets will not be recovered when the member restarts. Any temporary results still on
 * disk when a member restarts will be deleted.
 *
 */
public class TemporaryResultSetFactory {


  /**
   * Get a result set that is sorted. The result set will be overflowed on to disk as necessary, but
   * it will not be recovered from disk.
   * 
   * @param extractor a callback to extract the index sort key from the object. The sort key is
   *        expected to be comparable.
   * @param reverse - true to reverse the natural order of the keys
   */
  public ResultSet getSortedResultSet(SortKeyExtractor extractor, boolean reverse) {
    return new SortedResultSetImpl(extractor, reverse);
  }

  /**
   * Get a result bag that is sorted. The result set will be overflowed on to disk as necessary, but
   * it will not be recovered from disk.
   * 
   * @param extractor a callback to extract the index sort key from the object. The sort key is
   *        expected to be comparable.
   * @param reverse - true to reverse the natural order of the keys
   */
  public ResultBag getSortedResultBag(SortKeyExtractor extractor, boolean reverse) {
    return new SortedResultBagImpl(extractor, reverse);
  }

  /**
   * Get a result set that is not sorted. The result set will be overflowed on to disk as necessary,
   * but it will not be recovered from disk.
   * 
   * This is useful for cases where the ordering is not important, but the set semantics are. For
   * example, a distinct query.
   * 
   * @param reverse - true to reverse the natural order of the keys
   */
  public ResultSet getUnsortedResultSet(boolean reverse) {
    return new SortedResultSetImpl(null, reverse);
  }

  /**
   * Get a list to store temporary results. The list will be overflowed on to disk as necessary, but
   * it will not be recovered from disk.
   * 
   */
  public ResultList getResultList() {
    return new ResultListImpl();
  }
}