/**
* 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.twitter.maple.hbase;
import cascading.flow.FlowProcess;
import cascading.flow.hadoop.HadoopFlowProcess;
import cascading.tap.Tap;
import cascading.tap.TapException;
import cascading.tuple.TupleEntrySchemeCollector;
import org.apache.hadoop.mapred.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
/**
* Class HBaseTapCollector is a kind of
* {@link cascading.tuple.TupleEntrySchemeCollector} that writes tuples to the
* resource managed by a particular {@link HBaseTap} instance.
*/
public class HBaseTapCollector extends TupleEntrySchemeCollector implements OutputCollector {
/** Field LOG */
private static final Logger LOG = LoggerFactory.getLogger(HBaseTapCollector.class);
/** Field conf */
private final JobConf conf;
/** Field writer */
private RecordWriter writer;
/** Field flowProcess */
private final FlowProcess<JobConf> hadoopFlowProcess;
/** Field tap */
private final Tap<JobConf, RecordReader, OutputCollector> tap;
/** Field reporter */
private final Reporter reporter = Reporter.NULL;
/**
* Constructor TapCollector creates a new TapCollector instance.
*
* @param flowProcess
* @param tap
* of type Tap
* @throws IOException
* when fails to initialize
*/
public HBaseTapCollector(FlowProcess<JobConf> flowProcess, Tap<JobConf, RecordReader, OutputCollector> tap) throws IOException {
super(flowProcess, tap.getScheme());
this.hadoopFlowProcess = flowProcess;
this.tap = tap;
this.conf = new JobConf(flowProcess.getConfigCopy());
this.setOutput(this);
}
@Override
public void prepare() {
try {
initialize();
} catch (IOException e) {
throw new RuntimeException(e);
}
super.prepare();
}
private void initialize() throws IOException {
tap.sinkConfInit(hadoopFlowProcess, conf);
OutputFormat outputFormat = conf.getOutputFormat();
LOG.info("Output format class is: " + outputFormat.getClass().toString());
writer = outputFormat.getRecordWriter(null, conf, tap.getIdentifier(), Reporter.NULL);
sinkCall.setOutput(this);
}
@Override
public void close() {
try {
LOG.info("closing tap collector for: {}", tap);
writer.close(reporter);
} catch (IOException exception) {
LOG.warn("exception closing: {}", exception);
throw new TapException("exception closing HBaseTapCollector", exception);
} finally {
super.close();
}
}
/**
* Method collect writes the given values to the {@link Tap} this instance
* encapsulates.
*
* @param writableComparable
* of type WritableComparable
* @param writable
* of type Writable
* @throws IOException
* when
*/
public void collect(Object writableComparable, Object writable) throws IOException {
if (hadoopFlowProcess instanceof HadoopFlowProcess)
((HadoopFlowProcess) hadoopFlowProcess).getReporter().progress();
writer.write(writableComparable, writable);
}
}