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 com.dianping.cosmos;
  
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.TimeUnit;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.dp.blackhole.consumer.MessageStream;
  
  public class MessageFetcher implements Runnable {
      public static final Logger LOG = LoggerFactory.getLogger(MessageFetcher.class);
      private final int MAX_QUEUE_SIZE = 1000;
      private final int TIME_OUT = 5000;
  
      private BlockingQueue<String> emitQueue;
      private MessageStream stream;
  
      private volatile boolean running;
      public MessageFetcher(MessageStream stream) {
          this.running = true;
          this.stream = stream;
          this.emitQueue = new LinkedBlockingQueue<String>(MAX_QUEUE_SIZE);
      }
      
      @Override
      public void run() {
          while (running) {
              for (String message : stream) {
                  try {
                      while(!emitQueue.offer(message, TIME_OUT, TimeUnit.MILLISECONDS)) {
                          LOG.error("Queue is full, cannot offer message.");
                      }
                  } catch (InterruptedException e) {
                      LOG.error("Thread Interrupted");
                      running = false;
                  }
              }
          }
      }
      
      public String pollMessage() {
          return emitQueue.poll();
      }
      
      public void shutdown() {
          this.running = false;
      }
  }
  