edu.umd.shrawanraina.HBaseWordCountFetch.java Source code

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Here is the source code for edu.umd.shrawanraina.HBaseWordCountFetch.java

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/*
 * Cloud9: A MapReduce Library for Hadoop
 *
 * Licensed 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 edu.umd.shrawanraina;

import java.util.Arrays;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.GnuParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.OptionBuilder;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HConnection;
import org.apache.hadoop.hbase.client.HConnectionManager;
import org.apache.hadoop.hbase.client.HTableInterface;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.log4j.Logger;

/**
 * Simple demo of HBase; fetching word counts.
 *
 * @author Jimmy Lin
 */
public class HBaseWordCountFetch extends Configured implements Tool {
    private static final Logger LOG = Logger.getLogger(HBaseWordCountFetch.class);

    /**
     * Creates an instance of this tool.
     */
    public HBaseWordCountFetch() {
    }

    private static final String TABLE = "table";
    private static final String WORD = "word";

    /**
     * Runs this tool.
     */
    @SuppressWarnings({ "static-access" })
    public int run(String[] args) throws Exception {
        Options options = new Options();

        options.addOption(
                OptionBuilder.withArgName("table").hasArg().withDescription("HBase table name").create(TABLE));
        options.addOption(
                OptionBuilder.withArgName("word").hasArg().withDescription("word to look up").create(WORD));

        CommandLine cmdline;
        CommandLineParser parser = new GnuParser();

        try {
            cmdline = parser.parse(options, args);
        } catch (ParseException exp) {
            System.err.println("Error parsing command line: " + exp.getMessage());
            return -1;
        }

        if (!cmdline.hasOption(TABLE) || !cmdline.hasOption(WORD)) {
            System.out.println("args: " + Arrays.toString(args));
            HelpFormatter formatter = new HelpFormatter();
            formatter.setWidth(120);
            formatter.printHelp(this.getClass().getName(), options);
            ToolRunner.printGenericCommandUsage(System.out);
            return -1;
        }

        String tableName = cmdline.getOptionValue(TABLE);
        String word = cmdline.getOptionValue(WORD);

        Configuration conf = getConf();
        conf.addResource(new Path("/etc/hbase/conf/hbase-site.xml"));

        Configuration hbaseConfig = HBaseConfiguration.create(conf);
        HConnection hbaseConnection = HConnectionManager.createConnection(hbaseConfig);
        HTableInterface table = hbaseConnection.getTable(tableName);

        Get get = new Get(Bytes.toBytes(word));
        Result result = table.get(get);

        int count = Bytes.toInt(result.getValue(HBaseWordCount.CF, HBaseWordCount.COUNT));

        LOG.info("word: " + word + ", count: " + count);
        LOG.info("word: " + word + ", result: " + result.getValue(HBaseWordCount.CF, HBaseWordCount.COUNT));
        return 0;
    }

    /**
     * Dispatches command-line arguments to the tool via the {@code ToolRunner}.
     */
    public static void main(String[] args) throws Exception {
        ToolRunner.run(new HBaseWordCountFetch(), args);
    }
}