org.apache.hadoop.mapred.lib.aggregate
Class UserDefinedValueAggregatorDescriptor

java.lang.Object
  extended by org.apache.hadoop.mapreduce.lib.aggregate.UserDefinedValueAggregatorDescriptor
      extended by org.apache.hadoop.mapred.lib.aggregate.UserDefinedValueAggregatorDescriptor
All Implemented Interfaces:
ValueAggregatorDescriptor

@InterfaceAudience.Public
@InterfaceStability.Stable
public class UserDefinedValueAggregatorDescriptor
extends UserDefinedValueAggregatorDescriptor
implements ValueAggregatorDescriptor

This class implements a wrapper for a user defined value aggregator descriptor. It serves two functions: One is to create an object of ValueAggregatorDescriptor from the name of a user defined class that may be dynamically loaded. The other is to delegate invocations of generateKeyValPairs function to the created object.


Field Summary
 
Fields inherited from class org.apache.hadoop.mapreduce.lib.aggregate.UserDefinedValueAggregatorDescriptor
theAggregatorDescriptor
 
Fields inherited from interface org.apache.hadoop.mapred.lib.aggregate.ValueAggregatorDescriptor
ONE, TYPE_SEPARATOR
 
Constructor Summary
UserDefinedValueAggregatorDescriptor(String className, JobConf job)
           
 
Method Summary
 void configure(JobConf job)
          Do nothing.
static Object createInstance(String className)
          Create an instance of the given class
 
Methods inherited from class org.apache.hadoop.mapreduce.lib.aggregate.UserDefinedValueAggregatorDescriptor
configure, generateKeyValPairs, toString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface org.apache.hadoop.mapreduce.lib.aggregate.ValueAggregatorDescriptor
configure, generateKeyValPairs
 

Constructor Detail

UserDefinedValueAggregatorDescriptor

public UserDefinedValueAggregatorDescriptor(String className,
                                            JobConf job)
Parameters:
className - the class name of the user defined descriptor class
job - a configure object used for decriptor configuration
Method Detail

createInstance

public static Object createInstance(String className)
Create an instance of the given class

Parameters:
className - the name of the class
Returns:
a dynamically created instance of the given class

configure

public void configure(JobConf job)
Do nothing.

Parameters:
job - a JobConf object that may contain the information that can be used to configure the object.


Copyright © 2012 Apache Software Foundation. All Rights Reserved.