Package 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, ValueAggregatorDescriptor
@Public @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.

  • Constructor Details

    • 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 Details

    • 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.
      Specified by:
      configure in interface ValueAggregatorDescriptor
      Parameters:
      job - a JobConf object that may contain the information that can be used to configure the object.