com.sa.npopa.samples.hbase.myMR.java Source code

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Here is the source code for com.sa.npopa.samples.hbase.myMR.java

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/**
 *
 * 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.sa.npopa.samples.hbase;

/**
 * kinit hb580539
 * export HBASE_CLASSPATH=npopa-samples-0.0.1-SNAPSHOT.jar
 * hbase com.sa.npopa.samples.hbase.myMR table1
 * 
 */

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.filter.FirstKeyOnlyFilter;
import org.apache.hadoop.hbase.filter.KeyOnlyFilter;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.mapreduce.Counter;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.output.NullOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

@InterfaceAudience.Public
@InterfaceStability.Stable
public class myMR extends Configured implements Tool {

    private static final Log LOG = LogFactory.getLog(myMR.class);

    /** Name of this 'program'. */
    static final String NAME = "myMR";

    private final static String JOB_NAME_CONF_KEY = "mapreduce.job.name";

    /**
     * Mapper that runs the count.
     */
    static class RowCounterMapper extends TableMapper<ImmutableBytesWritable, Result> {

        /** Counter enumeration to count the actual rows. */
        public static enum Counters {
            ROWS, MALFORMED_ROWS
        }

        @Override
        public void map(ImmutableBytesWritable row, Result values, Context context) throws IOException {
            //Count rows based on the key condition
            //This need to be updated based on the malformed key condition. 
            if (Bytes.toString(row.get()).length() > 25 && Bytes.toString(row.get()).charAt(24) == 'a') {
                //StringBuilder myKey = new StringBuilder(Bytes.toString(row.get()));
                //myKey.setCharAt(24, 'x');
                //System.out.println("Oldkey:["+Bytes.toString(row.get())+"] Newkey:["+ myKey+"]");
                context.getCounter(Counters.MALFORMED_ROWS).increment(1);

            }
            //count all rows
            context.getCounter(Counters.ROWS).increment(1);
        }
    }

    public static Job createSubmittableJob(Configuration conf, String[] args) throws IOException {
        String tableName = args[0];

        Job job = Job.getInstance(conf, conf.get(JOB_NAME_CONF_KEY, NAME + "_" + tableName));
        job.setJarByClass(myMR.class);
        Scan scan = new Scan();
        scan.setCacheBlocks(false);
        scan.setBatch(10);

        //scan.setFilter(new FirstKeyOnlyFilter()); //need to find another filter like key only.
        scan.setFilter(new KeyOnlyFilter());

        job.setOutputFormatClass(NullOutputFormat.class);
        TableMapReduceUtil.initTableMapperJob(tableName, scan, RowCounterMapper.class, ImmutableBytesWritable.class,
                Result.class, job);
        job.setNumReduceTasks(0);
        return job;
    }

    /*
     * @param errorMessage Can attach a message when error occurs.
     */
    private static void printUsage(String errorMessage) {
        System.err.println("ERROR: " + errorMessage);
        printUsage();
    }

    private static void printUsage() {
        System.err.println("Usage: myMR [options] <tablename> ");
        System.err.println("For performance consider the following options:\n"
                + "-Dhbase.client.scanner.caching=100\n" + "-Dmapreduce.map.speculative=false");
    }

    @Override
    public int run(String[] args) throws Exception {
        if (args.length < 1) {
            printUsage("Wrong number of parameters: " + args.length);
            return -1;
        }
        Job job = createSubmittableJob(getConf(), args);
        if (job == null) {
            return -1;
        }
        boolean success = job.waitForCompletion(true);
        return (success ? 0 : 1);
    }

    public static void main(String[] args) throws Exception {
        int errCode = ToolRunner.run(HBaseConfiguration.create(), new myMR(), args);
        System.exit(errCode);
    }

}