/*
* 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.accumulo.core.client.mapred;
import java.io.IOException;
import java.util.Map.Entry;
import org.apache.accumulo.core.client.ClientConfiguration;
import org.apache.accumulo.core.client.RowIterator;
import org.apache.accumulo.core.client.security.tokens.AuthenticationToken;
import org.apache.accumulo.core.data.Key;
import org.apache.accumulo.core.data.Value;
import org.apache.accumulo.core.security.Authorizations;
import org.apache.accumulo.core.util.PeekingIterator;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.InputFormat;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapred.Reporter;
/**
* This class allows MapReduce jobs to use Accumulo as the source of data. This {@link InputFormat} provides row names as {@link Text} as keys, and a
* corresponding {@link PeekingIterator} as a value, which in turn makes the {@link Key}/{@link Value} pairs for that row available to the Map function.
*
* The user must specify the following via static configurator methods:
*
* <ul>
* <li>{@link AccumuloRowInputFormat#setConnectorInfo(JobConf, String, AuthenticationToken)}
* <li>{@link AccumuloRowInputFormat#setInputTableName(JobConf, String)}
* <li>{@link AccumuloRowInputFormat#setScanAuthorizations(JobConf, Authorizations)}
* <li>{@link AccumuloRowInputFormat#setZooKeeperInstance(JobConf, ClientConfiguration)} OR {@link AccumuloRowInputFormat#setMockInstance(JobConf, String)}
* </ul>
*
* Other static methods are optional.
*/
public class AccumuloRowInputFormat extends InputFormatBase<Text,PeekingIterator<Entry<Key,Value>>> {
@Override
public RecordReader<Text,PeekingIterator<Entry<Key,Value>>> getRecordReader(InputSplit split, JobConf job, Reporter reporter) throws IOException {
log.setLevel(getLogLevel(job));
RecordReaderBase<Text,PeekingIterator<Entry<Key,Value>>> recordReader = new RecordReaderBase<Text,PeekingIterator<Entry<Key,Value>>>() {
RowIterator rowIterator;
@Override
public void initialize(InputSplit inSplit, JobConf job) throws IOException {
super.initialize(inSplit, job);
rowIterator = new RowIterator(scannerIterator);
}
@Override
public boolean next(Text key, PeekingIterator<Entry<Key,Value>> value) throws IOException {
if (!rowIterator.hasNext())
return false;
value.initialize(rowIterator.next());
numKeysRead = rowIterator.getKVCount();
key.set((currentKey = value.peek().getKey()).getRow());
return true;
}
@Override
public Text createKey() {
return new Text();
}
@Override
public PeekingIterator<Entry<Key,Value>> createValue() {
return new PeekingIterator<Entry<Key,Value>>();
}
};
recordReader.initialize(split, job);
return recordReader;
}
}