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java.lang.Objectorg.apache.hadoop.mapred.MapReduceBase
org.apache.hadoop.hbase.mapred.IndexTableReduce
public class IndexTableReduce
Construct a Lucene document per row, which is consumed by IndexOutputFormat to build a Lucene index
Constructor Summary | |
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IndexTableReduce()
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Method Summary | |
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void |
close()
Default implementation that does nothing. |
void |
configure(JobConf job)
Default implementation that does nothing. |
void |
reduce(Text key,
Iterator<MapWritable> values,
OutputCollector<Text,org.apache.hadoop.hbase.mapred.LuceneDocumentWrapper> output,
Reporter reporter)
Reduces values for a given key. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public IndexTableReduce()
Method Detail |
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public void configure(JobConf job)
MapReduceBase
configure
in interface JobConfigurable
configure
in class MapReduceBase
job
- the configurationpublic void close() throws IOException
MapReduceBase
close
in interface Closeable
close
in class MapReduceBase
IOException
public void reduce(Text key, Iterator<MapWritable> values, OutputCollector<Text,org.apache.hadoop.hbase.mapred.LuceneDocumentWrapper> output, Reporter reporter) throws IOException
Reducer
The framework calls this method for each
<key, (list of values)>
pair in the grouped inputs.
Output values must be of the same type as input values. Input keys must
not be altered. Typically all values are combined into zero or one value.
Output pairs are collected with calls to
OutputCollector.collect(WritableComparable,Writable)
.
Applications can use the Reporter
provided to report progress
or just indicate that they are alive. In scenarios where the application
takes an insignificant amount of time to process individual key/value
pairs, this is crucial since the framework might assume that the task has
timed-out and kill that task. The other way of avoiding this is to set
mapred.task.timeout to a high-enough value (or even zero for no
time-outs).
reduce
in interface Reducer<Text,MapWritable,Text,org.apache.hadoop.hbase.mapred.LuceneDocumentWrapper>
key
- the key.values
- the list of values to reduce.output
- to collect keys and combined values.reporter
- facility to report progress.
IOException
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