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.solr.search;
  
  import java.io.IOException;
  
  /**
   * Implementations of <code>CacheRegenerator</code> are used in autowarming to populate a new cache
   * based on an old cache.  <code>regenerateItem</code> is called for each item that should be inserted into the new cache.
   * <p>
   * Implementations should have a noarg constructor and be thread safe (a single instance will be
   * used for all cache autowarmings).
   *
   * @version $Id: CacheRegenerator.java 555343 2007-07-11 17:46:25Z hossman $
   */
  public interface CacheRegenerator {
    /**
     * Regenerate an old cache item and insert it into <code>newCache</code>
     *
     * @param newSearcher the new searcher who's caches are being autowarmed
     * @param newCache    where regenerated cache items should be stored. the target of the autowarming
     * @param oldCache    the old cache being used as a source for autowarming
     * @param oldKey      the key of the old cache item to regenerate in the new cache
     * @param oldVal      the old value of the cache item
     * @return true to continue with autowarming, false to stop
     */
    public boolean regenerateItem(SolrIndexSearcher newSearcher, SolrCache newCache, SolrCache oldCache, Object oldKey, Object oldVal) throws IOException;
  }
  