org.apache.hadoop.mapred.lib.aggregate
Class UserDefinedValueAggregatorDescriptor
java.lang.Object
org.apache.hadoop.mapreduce.lib.aggregate.UserDefinedValueAggregatorDescriptor
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 servs 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
deligate inviokations of generateKeyValPairs function to the created object.
UserDefinedValueAggregatorDescriptor
public UserDefinedValueAggregatorDescriptor(String className,
JobConf job)
- Parameters:
className
- the class name of the user defined descriptor classjob
- a configure object used for decriptor configuration
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 © 2009 The Apache Software Foundation