edu.american.student.redis.hadoop.RedisBigTableRecordReader.java Source code

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Here is the source code for edu.american.student.redis.hadoop.RedisBigTableRecordReader.java

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/**
 * <br>
 * Licensed under the Apache License, Version 2.0 (the "License");<br>
 * you may not use this file except in compliance with the License.<br>
 * You may obtain a copy of the License at<br>
 * <br>
 * http://www.apache.org/licenses/LICENSE-2.0<br>
 * <br>
 * Unless required by applicable law or agreed to in writing, software<br>
 * distributed under the License is distributed on an "AS IS" BASIS,<br>
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<br>
 * See the License for the specific language governing permissions and<br>
 * limitations under the License.<br>
 */
package edu.american.student.redis.hadoop;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;

import edu.american.student.redis.MessageFactory;
import edu.american.student.redis.foreman.RedisForeman;
import edu.american.student.redis.foreman.RedisForemanException;

public class RedisBigTableRecordReader extends RecordReader<RedisBigTableKey, Text> {
    private Iterator<Entry<RedisBigTableKey, byte[]>> keyValueMapIter = null;
    private Entry<RedisBigTableKey, byte[]> currentEntry = null;
    private RedisBigTableKey key = null;
    private Text value = new Text();
    private float totalKVs = 0;
    private float processedKVs = 0;

    @Override
    public void close() throws IOException {

    }

    @Override
    public RedisBigTableKey getCurrentKey() throws IOException, InterruptedException {
        return key;
    }

    @Override
    public Text getCurrentValue() throws IOException, InterruptedException {
        return value;
    }

    @Override
    public float getProgress() throws IOException, InterruptedException {
        return processedKVs / totalKVs;
    }

    @Override
    public void initialize(InputSplit split, TaskAttemptContext context) throws IOException, InterruptedException {
        String[] locations = split.getLocations();
        RedisBigTableKey key = RedisBigTableKey.inflate(locations[0].getBytes());
        byte[] row = key.getRow();
        byte[] cf = key.getColumnFamily();
        byte[] cq = key.getColumnQualifier();
        RedisForeman foreman = new RedisForeman();
        foreman.connect();
        Map<RedisBigTableKey, byte[]> keyValues;
        try {
            keyValues = foreman.getByQualifier(locations[1].getBytes(), row, cf, cq);
            totalKVs = keyValues.size();
            keyValueMapIter = keyValues.entrySet().iterator();
        } catch (RedisForemanException e) {
            throw new IOException(MessageFactory.objective("Read Split").toString(), e);
        }
    }

    @Override
    public boolean nextKeyValue() throws IOException, InterruptedException {
        if (keyValueMapIter.hasNext()) {
            currentEntry = keyValueMapIter.next();
            key = currentEntry.getKey();
            value.set(currentEntry.getValue());
            processedKVs++;
            return true;
        }
        return false;
    }

}