/**
* 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 org.apache.hcatalog.data.transfer.impl;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.TaskAttemptID;
import org.apache.hcatalog.common.ErrorType;
import org.apache.hcatalog.common.HCatException;
import org.apache.hcatalog.data.HCatRecord;
import org.apache.hcatalog.data.transfer.HCatReader;
import org.apache.hcatalog.data.transfer.ReadEntity;
import org.apache.hcatalog.data.transfer.ReaderContext;
import org.apache.hcatalog.data.transfer.state.StateProvider;
import org.apache.hcatalog.mapreduce.HCatInputFormat;
import org.apache.hcatalog.shims.HCatHadoopShims;
/**
* This reader reads via {@link HCatInputFormat}
*
*/
public class HCatInputFormatReader extends HCatReader {
private InputSplit split;
public HCatInputFormatReader(InputSplit split, Configuration config,
StateProvider sp) {
super(config, sp);
this.split = split;
}
public HCatInputFormatReader(ReadEntity info, Map<String, String> config) {
super(info, config);
}
@Override
public ReaderContext prepareRead() throws HCatException {
try {
Job job = new Job(conf);
HCatInputFormat hcif = HCatInputFormat.setInput(
job, re.getDbName(), re.getTableName()).setFilter(re.getFilterString());
ReaderContext cntxt = new ReaderContext();
cntxt.setInputSplits(hcif.getSplits(
HCatHadoopShims.Instance.get().createJobContext(job.getConfiguration(), null)));
cntxt.setConf(job.getConfiguration());
return cntxt;
} catch (IOException e) {
throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
} catch (InterruptedException e) {
throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
}
}
@Override
public Iterator<HCatRecord> read() throws HCatException {
HCatInputFormat inpFmt = new HCatInputFormat();
RecordReader<WritableComparable, HCatRecord> rr;
try {
TaskAttemptContext cntxt = HCatHadoopShims.Instance.get().createTaskAttemptContext(conf, new TaskAttemptID());
rr = inpFmt.createRecordReader(split, cntxt);
rr.initialize(split, cntxt);
} catch (IOException e) {
throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
} catch (InterruptedException e) {
throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
}
return new HCatRecordItr(rr);
}
private static class HCatRecordItr implements Iterator<HCatRecord> {
private RecordReader<WritableComparable, HCatRecord> curRecReader;
HCatRecordItr(RecordReader<WritableComparable, HCatRecord> rr) {
curRecReader = rr;
}
@Override
public boolean hasNext() {
try {
boolean retVal = curRecReader.nextKeyValue();
if (retVal) {
return true;
}
// if its false, we need to close recordReader.
curRecReader.close();
return false;
} catch (IOException e) {
throw new RuntimeException(e);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
@Override
public HCatRecord next() {
try {
return curRecReader.getCurrentValue();
} catch (IOException e) {
throw new RuntimeException(e);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException("Not allowed");
}
}
}