/*
* Copyright 2009-2013 Scale Unlimited
*
* Licensed 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 bixo.examples.crawl;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.scaleunlimited.cascading.NullContext;
import bixo.datum.StatusDatum;
import bixo.datum.UrlDatum;
import bixo.datum.UrlStatus;
import cascading.flow.FlowProcess;
import cascading.operation.BaseOperation;
import cascading.operation.Function;
import cascading.operation.FunctionCall;
import cascading.operation.OperationCall;
@SuppressWarnings({"serial", "rawtypes"})
public class CreateUrlDatumFromStatusFunction extends BaseOperation<NullContext> implements Function<NullContext> {
private static final Logger LOGGER = LoggerFactory.getLogger(CreateUrlDatumFromStatusFunction.class);
private int _numCreated;
public CreateUrlDatumFromStatusFunction() {
super(UrlDatum.FIELDS);
}
@Override
public void prepare(FlowProcess process, OperationCall<NullContext> operationCall) {
LOGGER.info("Starting creation of URLs from status");
_numCreated = 0;
}
@Override
public void cleanup(FlowProcess process, OperationCall<NullContext> operationCall) {
LOGGER.info("Ending creation of URLs from status");
LOGGER.info(String.format("Created %d URLs", _numCreated));
}
@Override
public void operate(FlowProcess process, FunctionCall<NullContext> funcCall) {
StatusDatum datum = new StatusDatum(funcCall.getArguments());
UrlStatus status = datum.getStatus();
String url = datum.getUrl();
long statusTime = datum.getStatusTime();
long fetchTime = statusTime; // Not exactly true... since in some cases we
// may not have fetched the url. But because we are sharing this logic
// between the JDBCCrawlTool and the DemoCrawlTool, we use the value
// of the fetchTime while selecting the "latest" url. Newly added urls
// have a fetchTime of 0, so in order to preserve say a SKIPPED status
// we set the fetch time here.
_numCreated += 1;
UrlDatum urlDatum = new UrlDatum(url);
urlDatum.setPayloadValue(CrawlDbDatum.LAST_FETCHED_FIELD, fetchTime);
urlDatum.setPayloadValue(CrawlDbDatum.LAST_UPDATED_FIELD, statusTime);
urlDatum.setPayloadValue(CrawlDbDatum.LAST_STATUS_FIELD, status.name());
// Don't change the crawl depth here - we do that only in the case of a
// successful parse
urlDatum.setPayloadValue(CrawlDbDatum.CRAWL_DEPTH, datum.getPayloadValue(CrawlDbDatum.CRAWL_DEPTH));
funcCall.getOutputCollector().add(urlDatum.getTuple());
}
}