/**
* Licensed to DigitalPebble Ltd under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* DigitalPebble 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.digitalpebble.storm.crawler.bolt;
import java.util.Map;
import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;
import backtype.storm.tuple.Values;
import com.digitalpebble.storm.crawler.Metadata;
import com.digitalpebble.storm.crawler.persistence.Status;
/***
* Any tuple that went through all the previous bolts is sent to the status
* stream with a Status of FETCHED. This allows the bolt in charge of storing
* the status to rely exclusively on the status stream.
**/
@SuppressWarnings("serial")
public class StatusStreamBolt extends BaseRichBolt {
OutputCollector collector;
@Override
public void execute(Tuple tuple) {
String url = tuple.getStringByField("url");
Metadata metadata = (Metadata) tuple.getValueByField("metadata");
collector.emit(
com.digitalpebble.storm.crawler.Constants.StatusStreamName,
tuple, new Values(url, metadata, Status.FETCHED));
collector.ack(tuple);
}
@Override
public void prepare(Map conf, TopologyContext context,
OutputCollector collector) {
this.collector = collector;
}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declareStream(
com.digitalpebble.storm.crawler.Constants.StatusStreamName,
new Fields("url", "metadata", "status"));
}
}