Java tutorial
package com.digitalpebble.behemoth.mahout; /** * 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. */ import java.io.IOException; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat; import org.apache.lucene.analysis.Analyzer; import org.apache.mahout.common.HadoopUtil; import org.apache.mahout.common.StringTuple; import com.digitalpebble.behemoth.BehemothDocument; /** * This class converts a set of input documents in the sequence file format of * {@link StringTuple}s.The {@link org.apache.hadoop.io.SequenceFile} input * should have a {@link Text} key containing the unique document identifier and * a {@link BehemothDocument} value containing the whole document. * */ public final class BehemothDocumentProcessor { public static final String TOKENIZED_DOCUMENT_OUTPUT_FOLDER = "tokenized-documents"; public static final String TOKEN_TYPE = "Token.type"; public static final String FEATURE_NAME = "Feature.name"; public static final String ANALYZER_CLASS = "analyzer.class"; public static final String MD_LABEL = "Metadata.Key.Label"; // public static final Charset CHARSET = Charset.forName("UTF-8"); /** * Cannot be initialized. Use the static functions */ private BehemothDocumentProcessor() { } /** * Convert the input documents into token array using the * {@link StringTuple} The input documents has to be in the * {@link org.apache.hadoop.io.SequenceFile} format * * @param input * input directory of the documents in * {@link org.apache.hadoop.io.SequenceFile} format * @param output * output directory were the {@link StringTuple} token array of * each document has to be created * @param type * The annotation type representing the tokens * @param feature * The name of the features holding the token value * @throws IOException * @throws ClassNotFoundException * @throws InterruptedException */ public static void tokenizeDocuments(Path input, String type, String feature, Path output) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(); // this conf parameter needs to be set enable serialisation of conf // values conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization," + "org.apache.hadoop.io.serializer.WritableSerialization"); conf.set(TOKEN_TYPE, type); conf.set(FEATURE_NAME, feature); Job job = new Job(conf); job.setJobName("DocumentProcessor::BehemothTokenizer: input-folder: " + input); job.setJarByClass(BehemothDocumentProcessor.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(StringTuple.class); FileInputFormat.setInputPaths(job, input); FileOutputFormat.setOutputPath(job, output); job.setMapperClass(BehemothTokenizerMapper.class); job.setInputFormatClass(SequenceFileInputFormat.class); job.setNumReduceTasks(0); job.setOutputFormatClass(SequenceFileOutputFormat.class); HadoopUtil.delete(conf, output); boolean succeeded = job.waitForCompletion(true); if (!succeeded) throw new IllegalStateException("Job failed!"); } /** * Convert the input documents into token array using the * {@link StringTuple} The input documents has to be in the * {@link org.apache.hadoop.io.SequenceFile} format * * @param input * input directory of the documents in * {@link org.apache.hadoop.io.SequenceFile} format * @param output * output directory were the {@link StringTuple} token array of * each document has to be created * @param analyzerClass * The Lucene {@link Analyzer} for tokenizing the UTF-8 text */ public static void tokenizeDocuments(Path input, Class<? extends Analyzer> analyzerClass, Path output, Configuration baseConf) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(baseConf); // this conf parameter needs to be set enable serialisation of conf // values conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization," + "org.apache.hadoop.io.serializer.WritableSerialization"); conf.set(ANALYZER_CLASS, analyzerClass.getName()); Job job = new Job(conf); job.setJobName("DocumentProcessor::LuceneTokenizer: input-folder: " + input); job.setJarByClass(BehemothDocumentProcessor.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(StringTuple.class); FileInputFormat.setInputPaths(job, input); FileOutputFormat.setOutputPath(job, output); job.setMapperClass(LuceneTokenizerMapper.class); job.setInputFormatClass(SequenceFileInputFormat.class); job.setNumReduceTasks(0); job.setOutputFormatClass(SequenceFileOutputFormat.class); HadoopUtil.delete(conf, output); boolean succeeded = job.waitForCompletion(true); if (!succeeded) throw new IllegalStateException("Job failed!"); } public static void dumpLabels(Path input, Path output, Configuration baseConf) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(baseConf); // this conf parameter needs to be set enable serialisation of conf // values conf.set("io.serializations", "org.apache.hadoop.io.serializer.JavaSerialization," + "org.apache.hadoop.io.serializer.WritableSerialization"); Job job = new Job(conf); job.setJobName("DocumentProcessor::LabelDumper: input-folder: " + input); job.setJarByClass(BehemothDocumentProcessor.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(Text.class); FileInputFormat.setInputPaths(job, input); FileOutputFormat.setOutputPath(job, output); job.setMapperClass(BehemothLabelMapper.class); job.setInputFormatClass(SequenceFileInputFormat.class); job.setNumReduceTasks(0); job.setOutputFormatClass(SequenceFileOutputFormat.class); HadoopUtil.delete(conf, output); boolean succeeded = job.waitForCompletion(true); if (!succeeded) throw new IllegalStateException("Job failed!"); } }