/**
* 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.stormcrawler.indexing;
import static com.digitalpebble.stormcrawler.Constants.StatusStreamName;
import java.util.Iterator;
import java.util.Map;
import org.apache.storm.task.OutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.tuple.Values;
import com.digitalpebble.stormcrawler.Metadata;
import com.digitalpebble.stormcrawler.persistence.Status;
/**
* Indexer which generates fields for indexing and sends them to the standard
* output. Useful for debugging and as an illustration of what
* AbstractIndexerBolt provides.
*/
@SuppressWarnings("serial")
public class StdOutIndexer extends AbstractIndexerBolt {
OutputCollector _collector;
@SuppressWarnings("rawtypes")
@Override
public void prepare(Map conf, TopologyContext context,
OutputCollector collector) {
super.prepare(conf, context, collector);
_collector = collector;
}
@Override
public void execute(Tuple tuple) {
String url = tuple.getStringByField("url");
// Distinguish the value used for indexing
// from the one used for the status
String normalisedurl = valueForURL(tuple);
Metadata metadata = (Metadata) tuple.getValueByField("metadata");
// should this document be kept?
boolean keep = filterDocument(metadata);
if (!keep) {
// treat it as successfully processed even if
// we do not index it
_collector.emit(StatusStreamName, tuple, new Values(url, metadata,
Status.FETCHED));
_collector.ack(tuple);
return;
}
// display text of the document?
if (fieldNameForText() != null) {
String text = tuple.getStringByField("text");
System.out.println(fieldNameForText() + "\t" + trimValue(text));
}
if (fieldNameForURL() != null) {
System.out.println(fieldNameForURL() + "\t"
+ trimValue(normalisedurl));
}
// which metadata to display?
Map<String, String[]> keyVals = filterMetadata(metadata);
Iterator<String> iterator = keyVals.keySet().iterator();
while (iterator.hasNext()) {
String fieldName = iterator.next();
String[] values = keyVals.get(fieldName);
for (String value : values) {
System.out.println(fieldName + "\t" + trimValue(value));
}
}
_collector.emit(StatusStreamName, tuple, new Values(url, metadata,
Status.FETCHED));
_collector.ack(tuple);
}
private String trimValue(String value) {
if (value.length() > 100)
return value.length() + " chars";
return value;
}
}