Method Aggregate

Aggregate(Object)

This method takes in an object and contains the logic of applying the aggregation operation on the same node (locally) just like with the Combiner. If you wish to combine values using an aggregator before being sent for further processing in the Reducer, you can use the Aggregate() call.

Declaration
object Aggregate(object value)
Parameters
Type Name Description
System.Object value

Object.
Returns
Type Description
System.Object

Returns aggregated result.
Examples

The following example illustrates the implementation of Aggregate. 

string function;
//setting current aggregator function

public IntAggregator(string function)
{
   this.function = function;
}

//Implementing interface function

public object Aggregate(object value)
{
   return calculate(value);
}
//Function to calculate values

private object calculate(object value)
{
   switch (function)
   {
       case "MIN":
           value = int.MinValue;
           return value;
       case "MAX":
           value = int.MaxValue;
           return value;
       default:
           return 0;
   }
}