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.camel.component.rss;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import com.rometools.rome.feed.synd.SyndEntry;
  import com.rometools.rome.feed.synd.SyndFeed;
  import org.apache.camel.AggregationStrategy;
  import org.apache.camel.Exchange;
  import org.apache.camel.util.CastUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class AggregateRssFeedStrategy implements AggregationStrategy {
      protected final Logger log = LoggerFactory.getLogger(AggregateRssFeedStrategy.class);
  
      @Override
      public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
          if (oldExchange == null) {
              return newExchange;
          }
          SyndFeed oldFeed = oldExchange.getIn().getBody(SyndFeed.class);
          SyndFeed newFeed = newExchange.getIn().getBody(SyndFeed.class);
          if (oldFeed != null && newFeed != null) {
              List<SyndEntry> oldEntries = CastUtils.cast(oldFeed.getEntries());
              List<SyndEntry> newEntries = CastUtils.cast(newFeed.getEntries());
              List<SyndEntry> mergedList = new ArrayList<>(oldEntries.size() + newEntries.size());
              mergedList.addAll(oldEntries);
              mergedList.addAll(newEntries);
              oldFeed.setEntries(mergedList);
          } else {
              log.debug("Could not merge exchanges. One body was null.");
          }
          return oldExchange;
      }
  }
  