StreamingUnit

HelloWorldJob.cs

using Elastacloud.Hadoop.StreamingUnitExample.Job.Map;
using Elastacloud.Hadoop.StreamingUnitExample.Job.Reduce;
using Microsoft.Hadoop.MapReduce;

namespace Elastacloud.Hadoop.StreamingUnitExample.Job
{
    public class HelloWorldJob : HadoopJob<HelloWorldMapper, HelloWorldReducer>
    {
        public override HadoopJobConfiguration Configure(ExecutorContext context)
        {
            return new HadoopJobConfiguration();//here you would normally set up some input ;-)
        }
    }
}

HelloWorldMapper.cs

using Microsoft.Hadoop.MapReduce;

namespace Elastacloud.Hadoop.StreamingUnitExample.Job.Map
{
    public class HelloWorldMapper : MapperBase
    {
        public override void Map(string inputLine, MapperContext context)
        {
            //example input: Hello, Andy
            if (!inputLine.StartsWith("Hello, ")) return;

            var key = inputLine.Substring(7);
            if (key.EndsWith(".")) key = key.Trim('.');

            context.EmitKeyValue(key, "1");//we are going to count instances, the value is irrelevant
        }
    }
}

HelloWorldReducer.cs

using System.Collections.Generic;
using System.Linq;
using Microsoft.Hadoop.MapReduce;

namespace Elastacloud.Hadoop.StreamingUnitExample.Job.Reduce
{
    public class HelloWorldReducer : ReducerCombinerBase
    {
        public override void Reduce(string key, IEnumerable<string> values, ReducerCombinerContext context)
        {
            context.EmitKeyValue(key, values.Count().ToString());//count instances of this key
        }
    }
}

output.csv

Map
Andy    1
Andy    1
Andy    1
andy    1
chickenface     1
why doesn't this work!  1
Reduce
Andy    3
andy    1
chickenface     1
why doesn't this work!  1

Program.cs

using System;
using Elastacloud.Hadoop.StreamingUnitExample.Job.Map;
using Elastacloud.Hadoop.StreamingUnitExample.Job.Reduce;
using Microsoft.Hadoop.MapReduce;

namespace Elastacloud.Hadoop.StreamingUnitExample
{
    class Program
    {
        static void Main(string[] args)
        {
            var inputArray = new[]
                {
                    "Hello, Andy",
                    "Hello, andy",
                    "Hello, why doesn't this work!",
                    "Hello, Andy",
                    "Hello, chickenface",
                    "Hello, Andy"
                };

            var output =
                    StreamingUnit.Execute<HelloWorldMapper, HelloWorldReducer>(inputArray);

            Console.WriteLine("Map");
            foreach (var mapperResult in output.MapperResult)
            {
                Console.WriteLine(mapperResult);
            }

            Console.WriteLine("Reduce");
            foreach (var reducerResult in output.ReducerResult)
            {
                Console.WriteLine(reducerResult);
            }

            Console.ReadLine();

        }
    }
}