[21] | 1 | /** |
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| 2 | * Program: HBaseRecordPro.java |
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| 3 | * Editor: Waue Chen |
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| 4 | * From : NCHC. Taiwn |
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| 5 | * Last Update Date: 07/02/2008 |
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| 6 | */ |
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| 7 | /* |
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| 8 | * Cloud9: A MapReduce Library for Hadoop |
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| 9 | */ |
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| 10 | |
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| 11 | package tw.org.nchc.demo; |
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| 12 | |
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| 13 | import java.io.IOException; |
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| 14 | import java.util.Iterator; |
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| 15 | |
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| 16 | import org.apache.hadoop.fs.Path; |
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| 17 | import org.apache.hadoop.io.IntWritable; |
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| 18 | import org.apache.hadoop.io.LongWritable; |
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| 19 | import org.apache.hadoop.io.Text; |
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| 20 | import org.apache.hadoop.mapred.JobClient; |
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| 21 | import org.apache.hadoop.mapred.JobConf; |
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| 22 | import org.apache.hadoop.mapred.MapReduceBase; |
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| 23 | import org.apache.hadoop.mapred.Mapper; |
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| 24 | import org.apache.hadoop.mapred.OutputCollector; |
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| 25 | import org.apache.hadoop.mapred.Reducer; |
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| 26 | import org.apache.hadoop.mapred.Reporter; |
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| 27 | import org.apache.hadoop.mapred.SequenceFileInputFormat; |
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| 28 | import org.apache.hadoop.mapred.SequenceFileOutputFormat; |
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| 29 | |
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| 30 | import tw.org.nchc.tuple.ListWritable; |
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| 31 | import tw.org.nchc.tuple.Schema; |
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| 32 | import tw.org.nchc.tuple.Tuple; |
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| 33 | |
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| 34 | /** |
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| 35 | * <p> |
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| 36 | * Demo that illustrates the use of the tuple library ({@link Tuple} and |
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| 37 | * {@link ListWritable} class). Input comes from Bible+Shakespeare sample |
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| 38 | * collection, encoded with {@link DemoPackRecords2}. Otherwise, this demo is |
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| 39 | * exactly the same as {@link DemoWordCountTuple}. |
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| 40 | * </p> |
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| 41 | */ |
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| 42 | public class DemoWordCountTuple2 { |
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| 43 | |
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| 44 | // create the schema for the tuple that will serve as the key |
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| 45 | private static final Schema KEY_SCHEMA = new Schema(); |
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| 46 | |
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| 47 | // define the schema statically |
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| 48 | static { |
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| 49 | KEY_SCHEMA.addField("Token", String.class, ""); |
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| 50 | KEY_SCHEMA.addField("EvenOrOdd", Integer.class, new Integer(1)); |
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| 51 | } |
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| 52 | |
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| 53 | // mapper that emits tuple as the key, and value '1' for each occurrence |
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| 54 | private static class MapClass extends MapReduceBase implements |
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| 55 | Mapper<LongWritable, Tuple, Tuple, IntWritable> { |
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| 56 | |
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| 57 | // define value '1' statically so we can reuse the object, i.e., avoid |
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| 58 | // unnecessary object creation |
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| 59 | private final static IntWritable one = new IntWritable(1); |
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| 60 | |
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| 61 | // once again, reuse tuples if possible |
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| 62 | private Tuple tupleOut = KEY_SCHEMA.instantiate(); |
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| 63 | |
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| 64 | public void map(LongWritable key, Tuple tupleIn, |
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| 65 | OutputCollector<Tuple, IntWritable> output, Reporter reporter) |
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| 66 | throws IOException { |
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| 67 | |
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| 68 | @SuppressWarnings("unchecked") |
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| 69 | ListWritable<Text> list = (ListWritable<Text>) tupleIn.get(1); |
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| 70 | |
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| 71 | for (int i = 0; i < list.size(); i++) { |
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| 72 | Text t = (Text) list.get(i); |
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| 73 | |
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| 74 | String token = t.toString(); |
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| 75 | |
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| 76 | // put new values into the tuple |
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| 77 | tupleOut.set("Token", token); |
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| 78 | tupleOut.set("EvenOrOdd", ((Integer) tupleIn.get(0)) % 2); |
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| 79 | |
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| 80 | // emit key-value pair |
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| 81 | output.collect(tupleOut, one); |
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| 82 | } |
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| 83 | } |
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| 84 | } |
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| 85 | |
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| 86 | // reducer counts up tuple occurrences |
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| 87 | private static class ReduceClass extends MapReduceBase implements |
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| 88 | Reducer<Tuple, IntWritable, Tuple, IntWritable> { |
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| 89 | private final static IntWritable SumValue = new IntWritable(); |
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| 90 | |
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| 91 | public synchronized void reduce(Tuple tupleKey, |
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| 92 | Iterator<IntWritable> values, |
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| 93 | OutputCollector<Tuple, IntWritable> output, Reporter reporter) |
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| 94 | throws IOException { |
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| 95 | // sum values |
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| 96 | int sum = 0; |
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| 97 | while (values.hasNext()) { |
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| 98 | sum += values.next().get(); |
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| 99 | } |
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| 100 | |
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| 101 | // keep original tuple key, emit sum of counts as value |
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| 102 | SumValue.set(sum); |
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| 103 | output.collect(tupleKey, SumValue); |
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| 104 | } |
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| 105 | } |
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| 106 | |
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| 107 | // dummy constructor |
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| 108 | private DemoWordCountTuple2() { |
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| 109 | } |
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| 110 | |
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| 111 | /** |
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| 112 | * Runs the demo. |
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| 113 | */ |
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| 114 | public static void main(String[] args) throws IOException { |
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| 115 | String inPath = "/shared/sample-input/bible+shakes.nopunc.packed2"; |
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| 116 | String outputPath = "word-counts2-tuple"; |
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| 117 | int numMapTasks = 20; |
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| 118 | int numReduceTasks = 20; |
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| 119 | |
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| 120 | JobConf conf = new JobConf(DemoWordCountTuple2.class); |
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| 121 | conf.setJobName("wordcount"); |
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| 122 | |
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| 123 | conf.setNumMapTasks(numMapTasks); |
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| 124 | conf.setNumReduceTasks(numReduceTasks); |
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| 125 | |
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| 126 | // 0.16 |
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[28] | 127 | conf.setInputPath(new Path(inPath)); |
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| 128 | // Convert.setInputPath(conf,new Path(inPath)); |
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[21] | 129 | conf.setInputFormat(SequenceFileInputFormat.class); |
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| 130 | // 0.16 |
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[28] | 131 | conf.setOutputPath(new Path(outputPath)); |
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| 132 | // Convert.setInputPath(conf, new Path(outputPath)); |
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| 133 | |
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[21] | 134 | |
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| 135 | conf.setOutputKeyClass(Tuple.class); |
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| 136 | conf.setOutputValueClass(IntWritable.class); |
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| 137 | conf.setOutputFormat(SequenceFileOutputFormat.class); |
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| 138 | |
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| 139 | conf.setMapperClass(MapClass.class); |
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| 140 | conf.setCombinerClass(ReduceClass.class); |
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| 141 | conf.setReducerClass(ReduceClass.class); |
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| 142 | |
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| 143 | JobClient.runJob(conf); |
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| 144 | } |
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| 145 | } |
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