org.apache.gora.examples.mapreduce
Class QueryCounter<K,T extends Persistent>

java.lang.Object
  org.apache.hadoop.conf.Configured
      org.apache.gora.examples.mapreduce.QueryCounter<K,T>

All Implemented Interfaces:

org.apache.hadoop.conf.Configurable, org.apache.hadoop.util.Tool

public class QueryCounter<K,T extends Persistent>
extends org.apache.hadoop.conf.Configured
implements org.apache.hadoop.util.Tool

Example Hadoop job to count the row of a gora Query.

Nested Class Summary

static class

QueryCounter.QueryCounterMapper<K,T extends Persistent>

Field Summary

static String	COUNTER_GROUP
static String	ROWS

Constructor Summary

QueryCounter(org.apache.hadoop.conf.Configuration conf)

Method Summary

long	countQuery(DataStore<K,T> dataStore) Returns the number of results to the Query obtained by the getQuery(DataStore) method.
long	countQuery(DataStore<K,T> dataStore, Query<K,T> query) Returns the number of results to the Query
org.apache.hadoop.mapreduce.Job	createJob(DataStore<K,T> dataStore, Query<K,T> query) Creates and returns the Job for submitting to Hadoop mapreduce.
Query<K,T>	getQuery(DataStore<K,T> dataStore) Returns the Query to count the results of.
static void	main(String[] args)
int	run(String[] args)

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.hadoop.conf.Configurable

getConf, setConf

Field Detail

COUNTER_GROUP

public static final String COUNTER_GROUP

See Also:

Constant Field Values

ROWS

public static final String ROWS

See Also:

Constant Field Values

Constructor Detail

QueryCounter

public QueryCounter(org.apache.hadoop.conf.Configuration conf)

Method Detail

getQuery

public Query<K,T> getQuery(DataStore<K,T> dataStore)

Returns the Query to count the results of. Subclasses can override this function to customize the query.

Returns:

the Query object to count the results of.

createJob

public org.apache.hadoop.mapreduce.Job createJob(DataStore<K,T> dataStore,
                                                 Query<K,T> query)
                                          throws IOException

Creates and returns the Job for submitting to Hadoop mapreduce.

Parameters:

dataStore -

query -

Returns:

Throws:

IOException

countQuery

public long countQuery(DataStore<K,T> dataStore,
                       Query<K,T> query)
                throws Exception

Returns the number of results to the Query

Throws:

Exception

countQuery

public long countQuery(DataStore<K,T> dataStore)
                throws Exception

Returns the number of results to the Query obtained by the getQuery(DataStore) method.

Throws:

Exception

run

public int run(String[] args)
        throws Exception

Specified by:

run in interface org.apache.hadoop.util.Tool

Throws:

Exception

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception