RssEventProcessor.java

/*
 * 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
 *
 *   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.streams.rss.provider;

import org.apache.streams.core.StreamsDatum;
import org.apache.streams.pojo.json.Activity;
import org.apache.streams.rss.serializer.SyndEntryActivitySerializer;
import org.apache.streams.rss.serializer.SyndEntrySerializer;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.rometools.rome.feed.synd.SyndEntry;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Queue;
import java.util.Random;

/**
 * RssEventProcessor processes Rss Events.
 */
public class RssEventProcessor implements Runnable {

  private static final Logger LOGGER = LoggerFactory.getLogger(RssEventProcessor.class);

  private ObjectMapper mapper = new ObjectMapper();

  private Queue<SyndEntry> inQueue;
  private Queue<StreamsDatum> outQueue;

  private Class inClass;
  private Class outClass;

  private SyndEntryActivitySerializer syndEntryActivitySerializer = new SyndEntryActivitySerializer();
  private SyndEntrySerializer syndEntrySerializer = new SyndEntrySerializer();

  public static final String TERMINATE = new String("TERMINATE");

  /**
   * RssEventProcessor constructor.
   * @param inQueue inQueue
   * @param outQueue outQueue
   * @param inClass inClass
   * @param outClass outClass
   */
  public RssEventProcessor(Queue<SyndEntry> inQueue, Queue<StreamsDatum> outQueue, Class inClass, Class outClass) {
    this.inQueue = inQueue;
    this.outQueue = outQueue;
    this.inClass = inClass;
    this.outClass = outClass;
  }

  /**
   * RssEventProcessor constructor.
   * @param inQueue inQueue
   * @param outQueue outQueue
   * @param outClass outClass
   */
  public RssEventProcessor(Queue<SyndEntry> inQueue, Queue<StreamsDatum> outQueue, Class outClass) {
    this.inQueue = inQueue;
    this.outQueue = outQueue;
    this.outClass = outClass;
  }

  @Override
  public void run() {

    while (true) {
      Object item;
      try {
        item = inQueue.poll();
        if (item instanceof String && item.equals(TERMINATE)) {
          LOGGER.info("Terminating!");
          break;
        }

        Thread.sleep(new Random().nextInt(100));

        // if the target is string, just pass-through
        if ( String.class.equals(outClass)) {
          outQueue.offer(new StreamsDatum(item.toString()));
        } else if ( SyndEntry.class.equals(outClass)) {
          outQueue.offer(new StreamsDatum(item));
        } else if ( Activity.class.equals(outClass)) {
          // convert to desired format
          SyndEntry entry = (SyndEntry)item;
          if ( entry != null ) {
            Activity out = syndEntryActivitySerializer.deserialize(this.syndEntrySerializer.deserialize((SyndEntry)item));

            if ( out != null ) {
              outQueue.offer(new StreamsDatum(out));
            }
          }
        }

      } catch (Exception ex) {
        ex.printStackTrace();
      }
    }
  }

}