Barrier クラス

定義

public ref class Barrier : IDisposable

public class Barrier : IDisposable

[System.Runtime.InteropServices.ComVisible(false)]
public class Barrier : IDisposable

type Barrier = class
    interface IDisposable

[<System.Runtime.InteropServices.ComVisible(false)>]
type Barrier = class
    interface IDisposable

Public Class Barrier
Implements IDisposable

継承

Object

Barrier

属性

ComVisibleAttribute

実装

IDisposable

例

次の例は、バリアを使用する方法を示しています。

using System;
using System.Threading;
using System.Threading.Tasks;

class BarrierDemo
{
    // Demonstrates:
    //      Barrier constructor with post-phase action
    //      Barrier.AddParticipants()
    //      Barrier.RemoveParticipant()
    //      Barrier.SignalAndWait(), incl. a BarrierPostPhaseException being thrown
    static void BarrierSample()
    {
        int count = 0;

        // Create a barrier with three participants
        // Provide a post-phase action that will print out certain information
        // And the third time through, it will throw an exception
        Barrier barrier = new Barrier(3, (b) =>
        {
            Console.WriteLine("Post-Phase action: count={0}, phase={1}", count, b.CurrentPhaseNumber);
            if (b.CurrentPhaseNumber == 2) throw new Exception("D'oh!");
        });

        // Nope -- changed my mind.  Let's make it five participants.
        barrier.AddParticipants(2);

        // Nope -- let's settle on four participants.
        barrier.RemoveParticipant();

        // This is the logic run by all participants
        Action action = () =>
        {
            Interlocked.Increment(ref count);
            barrier.SignalAndWait(); // during the post-phase action, count should be 4 and phase should be 0
            Interlocked.Increment(ref count);
            barrier.SignalAndWait(); // during the post-phase action, count should be 8 and phase should be 1

            // The third time, SignalAndWait() will throw an exception and all participants will see it
            Interlocked.Increment(ref count);
            try
            {
                barrier.SignalAndWait();
            }
            catch (BarrierPostPhaseException bppe)
            {
                Console.WriteLine("Caught BarrierPostPhaseException: {0}", bppe.Message);
            }

            // The fourth time should be hunky-dory
            Interlocked.Increment(ref count);
            barrier.SignalAndWait(); // during the post-phase action, count should be 16 and phase should be 3
        };

        // Now launch 4 parallel actions to serve as 4 participants
        Parallel.Invoke(action, action, action, action);

        // This (5 participants) would cause an exception:
        // Parallel.Invoke(action, action, action, action, action);
        //      "System.InvalidOperationException: The number of threads using the barrier
        //      exceeded the total number of registered participants."

        // It's good form to Dispose() a barrier when you're done with it.
        barrier.Dispose();
    }
}

Imports System.Threading
Imports System.Threading.Tasks

Module BarrierSample

    ' Demonstrates:
    ' Barrier constructor with post-phase action
    ' Barrier.AddParticipants()
    ' Barrier.RemoveParticipant()
    ' Barrier.SignalAndWait(), incl. a BarrierPostPhaseException being thrown
    Sub Main()
        Dim count As Integer = 0

        ' Create a barrier with three participants
        ' Provide a post-phase action that will print out certain information
        ' And the third time through, it will throw an exception
        Dim barrier As New Barrier(3,
                                   Sub(b)
                                       Console.WriteLine("Post-Phase action: count={0}, phase={1}", count, b.CurrentPhaseNumber)
                                       If b.CurrentPhaseNumber = 2 Then
                                           Throw New Exception("D'oh!")
                                       End If
                                   End Sub)

        ' Nope -- changed my mind. Let's make it five participants.
        barrier.AddParticipants(2)

        ' Nope -- let's settle on four participants.
        barrier.RemoveParticipant()


        ' This is the logic run by all participants
        Dim action As Action =
            Sub()
                Interlocked.Increment(count)
                barrier.SignalAndWait()
                ' during the post-phase action, count should be 4 and phase should be 0

                Interlocked.Increment(count)
                barrier.SignalAndWait()
                ' during the post-phase action, count should be 8 and phase should be 1

                ' The third time, SignalAndWait() will throw an exception and all participants will see it
                Interlocked.Increment(count)
                Try
                    barrier.SignalAndWait()
                Catch bppe As BarrierPostPhaseException
                    Console.WriteLine("Caught BarrierPostPhaseException: {0}", bppe.Message)
                End Try

                ' The fourth time should be hunky-dory
                Interlocked.Increment(count)
                ' during the post-phase action, count should be 16 and phase should be 3
                barrier.SignalAndWait()

            End Sub

        ' Now launch 4 parallel actions to serve as 4 participants
        Parallel.Invoke(action, action, action, action)

        ' This (5 participants) would cause an exception:
        '   Parallel.Invoke(action, action, action, action, action)
        ' "System.InvalidOperationException: The number of threads using the barrier
        ' exceeded the total number of registered participants."

        ' It's good form to Dispose() a barrier when you're done with it.
        barrier.Dispose()
    End Sub
End Module

注釈

一連のフェーズを移動することで、一連のタスクのグループが連携し、グループ内のそれぞれが特定のフェーズに Barrier 到着したことを通知し、他のすべてのフェーズが到着するのを暗黙的に待機します。 同じ Barrier を複数のフェーズに使用できます。

コンストラクター

プロパティ

メソッド

適用対象

スレッド セーフ

パブリックメンバーとプロテクト メンバー Barrier はすべてスレッド セーフであり、Dispose を除き、複数のスレッドから同時に Barrier 使用できます。ただし、その他のすべての操作が完了した場合にのみ使用する必要があります。

こちらもご覧ください

• バリア
• 方法: バリアを使用して同時実行操作を同期する