mirror of https://github.com/apache/cassandra
207 lines
8.1 KiB
Java
207 lines
8.1 KiB
Java
/**
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* Licensed to the Apache Software Foundation (ASF) under one
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* or more contributor license agreements. See the NOTICE file
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* distributed with this work for additional information
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* regarding copyright ownership. The ASF licenses this file
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* to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.util.*;
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import org.apache.cassandra.thrift.Column;
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import org.apache.cassandra.thrift.ColumnOrSuperColumn;
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import org.apache.cassandra.thrift.Mutation;
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import org.apache.cassandra.hadoop.ColumnFamilyOutputFormat;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import static com.google.common.base.Charsets.UTF_8;
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import org.apache.cassandra.db.IColumn;
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import org.apache.cassandra.hadoop.ColumnFamilyInputFormat;
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import org.apache.cassandra.hadoop.ConfigHelper;
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import org.apache.cassandra.thrift.SlicePredicate;
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import org.apache.cassandra.utils.ByteBufferUtil;
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import org.apache.hadoop.conf.Configuration;
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import org.apache.hadoop.conf.Configured;
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import org.apache.hadoop.fs.Path;
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import org.apache.hadoop.io.IntWritable;
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import org.apache.hadoop.io.Text;
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import org.apache.hadoop.mapreduce.Job;
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import org.apache.hadoop.mapreduce.Mapper;
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import org.apache.hadoop.mapreduce.Reducer;
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import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
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import org.apache.hadoop.util.Tool;
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import org.apache.hadoop.util.ToolRunner;
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/**
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* This counts the occurrences of words in ColumnFamily Standard1, that has a single column (that we care about)
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* "text" containing a sequence of words.
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*
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* For each word, we output the total number of occurrences across all texts.
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*
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* When outputting to Cassandra, we write the word counts as a {word, count} column/value pair,
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* with a row key equal to the name of the source column we read the words from.
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*/
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public class WordCount extends Configured implements Tool
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{
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private static final Logger logger = LoggerFactory.getLogger(WordCount.class);
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static final String KEYSPACE = "wordcount";
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static final String COLUMN_FAMILY = "input_words";
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static final String OUTPUT_REDUCER_VAR = "output_reducer";
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static final String OUTPUT_COLUMN_FAMILY = "output_words";
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private static final String OUTPUT_PATH_PREFIX = "/tmp/word_count";
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private static final String CONF_COLUMN_NAME = "columnname";
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public static void main(String[] args) throws Exception
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{
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// Let ToolRunner handle generic command-line options
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ToolRunner.run(new Configuration(), new WordCount(), args);
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System.exit(0);
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}
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public static class TokenizerMapper extends Mapper<ByteBuffer, SortedMap<ByteBuffer, IColumn>, Text, IntWritable>
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{
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private final static IntWritable one = new IntWritable(1);
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private Text word = new Text();
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private ByteBuffer sourceColumn;
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protected void setup(org.apache.hadoop.mapreduce.Mapper.Context context)
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throws IOException, InterruptedException
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{
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sourceColumn = ByteBufferUtil.bytes(context.getConfiguration().get(CONF_COLUMN_NAME));
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}
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public void map(ByteBuffer key, SortedMap<ByteBuffer, IColumn> columns, Context context) throws IOException, InterruptedException
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{
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IColumn column = columns.get(sourceColumn);
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if (column == null)
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return;
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String value = ByteBufferUtil.string(column.value());
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logger.debug("read " + key + ":" + value + " from " + context.getInputSplit());
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StringTokenizer itr = new StringTokenizer(value);
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while (itr.hasMoreTokens())
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{
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word.set(itr.nextToken());
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context.write(word, one);
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}
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}
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}
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public static class ReducerToFilesystem extends Reducer<Text, IntWritable, Text, IntWritable>
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{
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public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException
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{
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int sum = 0;
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for (IntWritable val : values)
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sum += val.get();
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context.write(key, new IntWritable(sum));
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}
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}
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public static class ReducerToCassandra extends Reducer<Text, IntWritable, ByteBuffer, List<Mutation>>
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{
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private ByteBuffer outputKey;
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protected void setup(org.apache.hadoop.mapreduce.Reducer.Context context)
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throws IOException, InterruptedException
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{
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outputKey = ByteBufferUtil.bytes(context.getConfiguration().get(CONF_COLUMN_NAME));
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}
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public void reduce(Text word, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException
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{
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int sum = 0;
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for (IntWritable val : values)
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sum += val.get();
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context.write(outputKey, Collections.singletonList(getMutation(word, sum)));
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}
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private static Mutation getMutation(Text word, int sum)
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{
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Column c = new Column();
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c.setName(Arrays.copyOf(word.getBytes(), word.getLength()));
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c.setValue(ByteBufferUtil.bytes(String.valueOf(sum)));
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c.setTimestamp(System.currentTimeMillis());
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Mutation m = new Mutation();
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m.setColumn_or_supercolumn(new ColumnOrSuperColumn());
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m.column_or_supercolumn.setColumn(c);
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return m;
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}
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}
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public int run(String[] args) throws Exception
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{
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String outputReducerType = "filesystem";
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if (args != null && args[0].startsWith(OUTPUT_REDUCER_VAR))
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{
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String[] s = args[0].split("=");
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if (s != null && s.length == 2)
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outputReducerType = s[1];
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}
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logger.info("output reducer type: " + outputReducerType);
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for (int i = 0; i < WordCountSetup.TEST_COUNT; i++)
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{
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String columnName = "text" + i;
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getConf().set(CONF_COLUMN_NAME, columnName);
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Job job = new Job(getConf(), "wordcount");
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job.setJarByClass(WordCount.class);
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job.setMapperClass(TokenizerMapper.class);
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if (outputReducerType.equalsIgnoreCase("filesystem"))
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{
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job.setCombinerClass(ReducerToFilesystem.class);
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job.setReducerClass(ReducerToFilesystem.class);
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job.setOutputKeyClass(Text.class);
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job.setOutputValueClass(IntWritable.class);
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FileOutputFormat.setOutputPath(job, new Path(OUTPUT_PATH_PREFIX + i));
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}
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else
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{
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job.setReducerClass(ReducerToCassandra.class);
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job.setMapOutputKeyClass(Text.class);
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job.setMapOutputValueClass(IntWritable.class);
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job.setOutputKeyClass(ByteBuffer.class);
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job.setOutputValueClass(List.class);
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job.setOutputFormatClass(ColumnFamilyOutputFormat.class);
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ConfigHelper.setOutputColumnFamily(job.getConfiguration(), KEYSPACE, OUTPUT_COLUMN_FAMILY);
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}
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job.setInputFormatClass(ColumnFamilyInputFormat.class);
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ConfigHelper.setRpcPort(job.getConfiguration(), "9160");
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ConfigHelper.setInitialAddress(job.getConfiguration(), "localhost");
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ConfigHelper.setPartitioner(job.getConfiguration(), "org.apache.cassandra.dht.RandomPartitioner");
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ConfigHelper.setInputColumnFamily(job.getConfiguration(), KEYSPACE, COLUMN_FAMILY);
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SlicePredicate predicate = new SlicePredicate().setColumn_names(Arrays.asList(ByteBufferUtil.bytes(columnName)));
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ConfigHelper.setInputSlicePredicate(job.getConfiguration(), predicate);
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job.waitForCompletion(true);
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}
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return 0;
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}
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}
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