MapReduce PLinq 简单示例

namespace Microshaoft
{
    using System;
    using System.Linq;
    using System.Threading.Tasks;
    using System.Collections.Generic;
    using System.Collections.Concurrent;
    class Program
    {
        static void Main(string[] args)
        {
            var list = new List<Employee>()
                                    {
                                        new Employee()
                                                {
                                                    ID = 1
                                                    , Name = "Bill Gates"
                                                    , Department = "Microsoft"
                                                }
                                        , new Employee()
                                                {
                                                    ID = 2
                                                    , Name = "Steve Jobs"
                                                    , Department = "Apple"
                                                }
                                        , new Employee()
                                                {
                                                    ID = 3
                                                    , Name = "Larry Page"
                                                    , Department = "Google"
                                                }
                                        , new Employee()
                                                {
                                                    ID = 4
                                                    , Name = "Sergey Brin"
                                                    , Department = "Google"
                                                }
                                    };
            //按Department分组映射
            var mapper = list.AsParallel().ToLookup
                                            (
                                                x => x.Department
                                                , x => x
                                                // x => 0
                                            ).AsParallel();
            ConcurrentDictionary<string, int> result = new ConcurrentDictionary<string, int>();
            mapper.ForAll
            //mapper.ToList().ForEach
                            (
                                x =>
                                {
                                    Console.WriteLine(x.Key);
                                    //to do 分布式远程调用计算
                                    if (result.TryAdd(x.Key, x.Count())) //保存分布式结果到ConcurrentDictionary
                                    {
                                        x.AsParallel().ForAll
                                        //x.ToList().ForEach
                                                        (
                                                            xx =>
                                                            {
                                                                Console.WriteLine("{0},{1}", x.Key, xx.Name);
                                                            }
                                                        );
                                    }
                                }
                            );
            //返回所有分布式结果
            result.AsParallel().ForAll
                                    (
                                        kvp =>
                                        {
                                            Console.WriteLine("{0},{1}", kvp.Key, kvp.Value);
                                        }
                                    );
            //化简统计
            var reducer =
                            from
                                    IGrouping<string, Employee> groupingMapper
                                        in mapper.AsParallel()
                            select
                                    new
                                    {
                                        Department = groupingMapper.Key
                                        ,
                                        Count = groupingMapper.Count()
                                    };
            reducer.ForAll
                        (
                            x =>
                            {
                                Console.WriteLine("当前 Department = {0} 的人数有: {1} 人", x.Department, x.Count);
                            }
                        );
            var sum = reducer.Sum
                        (
                            x => x.Count
                        );
            Console.WriteLine("总人数有: {0} 人", sum);
            Console.ReadLine();
        }
        public class Employee
        {
            public int ID
            {
                get;
                set;
            }
            public string Name
            {
                get;
                set;
            }
            public string Department
            {
                get;
                set;
            }
            public string Gender
            {
                get;
                set;
            }
            public DateTime Birthday
            {
                get;
                set;
            }
        }
    }
}
//===========================================================
namespace Test
{
    using System;
    using System.Linq;
    using Microshaoft;
        /// <summary>
        /// Class1 的摘要说明。
        /// </summary>
    public class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        //[STAThread]
        static void Main(string[] args)
        {
            //
            // TODO: 在此处添加代码以启动应用程序
            //
            var r = MapReduceHelper
                        .Start<string, int, string>
                            (
                                (x) =>
                                    {
                                        return x.Length;
                                    } //Map
                                , (x) =>
                                    {
                                        return x.Sum().ToString();
                                    } //Reduce
                                , "aaaaaaaaaaaa"
                                , "bbbbbbbbb"
                                , "ccccccccccccc"
                            ).Result;
            Console.WriteLine(r);
            Console.WriteLine(Environment.Version.ToString());
        }
    }
}
namespace Microshaoft
{
    using System;
    using System.Linq;
    using System.Threading.Tasks;
    public static class MapReduceHelper
    {
        public static Task<TResult> Start<TInput, TPartialResult, TResult>
                                        (
                                            Func<TInput, TPartialResult> map
                                            , Func<TPartialResult[], TResult> reduce
                                            , params TInput[] inputs
                                        )
        {
            var mapTasks = CreateMapTasks(map, inputs);
            var reduceTask = CreateReduceTask(reduce, mapTasks);
            return reduceTask;
        }
        private static Task<TResult> CreateReduceTask<TPartialResult, TResult>
                                        (
                                            Func<TPartialResult[]
                                            , TResult> reduce
                                            , Task<TPartialResult>[] mapTasks
                                        )
        {
            return
                Task
                    .Factory
                        .ContinueWhenAll
                            (
                                mapTasks
                                , (tasks) =>
                                    {
                                        return
                                            PerformReduce(reduce, tasks);
                                    }
                            );
        }
        private static TResult PerformReduce<TPartialResult, TResult>
                                        (
                                            Func<TPartialResult[], TResult> reduce
                                            , Task<TPartialResult>[] tasks
                                        )
        {
            var results =
                            from
                                task
                            in
                                tasks
                            select
                                task.Result;
            return reduce(results.ToArray());
        }
        private static Task<TPartialResult>[] CreateMapTasks<TInput, TPartialResult>
                                        (
                                            Func<TInput, TPartialResult> map
                                            , TInput[] inputs
                                        )
        {
            var tasks = new Task<TPartialResult>[inputs.Length];
            for (int i = 0; i < inputs.Length; ++i)
            {
                var input = inputs[i];
                tasks[i] = Task
                                .Factory
                                    .StartNew
                                        (
                                            () => map(input)
                                        );
            }
            return tasks;
        }
    }
}