/**
* Copyright 2008 The Apache Software Foundation
*
* 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.hadoop.hbase.mapreduce;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.KeyValue;
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.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.output.NullOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
/**
* A job with a just a map phase to count rows. Map outputs table rows IF the
* input row has columns that have content.
*/
public class RowCounter {
/** Name of this 'program'. */
static final String NAME = "rowcounter";
/**
* Mapper that runs the count.
*/
static class RowCounterMapper
extends TableMapper<ImmutableBytesWritable, Result> {
/** Counter enumeration to count the actual rows. */
public static enum Counters {ROWS}
/**
* Maps the data.
*
* @param row The current table row key.
* @param values The columns.
* @param context The current context.
* @throws IOException When something is broken with the data.
* @see org.apache.hadoop.mapreduce.Mapper#map(KEYIN, VALUEIN,
* org.apache.hadoop.mapreduce.Mapper.Context)
*/
@Override
public void map(ImmutableBytesWritable row, Result values,
Context context)
throws IOException {
// Count every row containing data, whether it's in qualifiers or values
context.getCounter(Counters.ROWS).increment(1);
}
}
/**
* Sets up the actual job.
*
* @param conf The current configuration.
* @param args The command line parameters.
* @return The newly created job.
* @throws IOException When setting up the job fails.
*/
public static Job createSubmittableJob(Configuration conf, String[] args)
throws IOException {
String tableName = args[0];
Job job = new Job(conf, NAME + "_" + tableName);
job.setJarByClass(RowCounter.class);
// Columns are space delimited
StringBuilder sb = new StringBuilder();
final int columnoffset = 1;
for (int i = columnoffset; i < args.length; i++) {
if (i > columnoffset) {
sb.append(" ");
}
sb.append(args[i]);
}
Scan scan = new Scan();
scan.setFilter(new FirstKeyOnlyFilter());
if (sb.length() > 0) {
for (String columnName :sb.toString().split(" ")) {
String [] fields = columnName.split(":");
if(fields.length == 1) {
scan.addFamily(Bytes.toBytes(fields[0]));
} else {
scan.addColumn(Bytes.toBytes(fields[0]), Bytes.toBytes(fields[1]));
}
}
}
// Second argument is the table name.
job.setOutputFormatClass(NullOutputFormat.class);
TableMapReduceUtil.initTableMapperJob(tableName, scan,
RowCounterMapper.class, ImmutableBytesWritable.class, Result.class, job);
job.setNumReduceTasks(0);
return job;
}
/**
* Main entry point.
*
* @param args The command line parameters.
* @throws Exception When running the job fails.
*/
public static void main(String[] args) throws Exception {
Configuration conf = HBaseConfiguration.create();
String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
if (otherArgs.length < 1) {
System.err.println("ERROR: Wrong number of parameters: " + args.length);
System.err.println("Usage: RowCounter <tablename> [<column1> <column2>...]");
System.exit(-1);
}
Job job = createSubmittableJob(conf, otherArgs);
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}