ConcurrentExclusiveSchedulerPair Class

Definition

Namespace:

System.Threading.Tasks

Assembly:

System.Runtime.dll

Source:

ConcurrentExclusiveSchedulerPair.cs

Provides task schedulers that coordinate to execute tasks while ensuring that concurrent tasks may run concurrently and exclusive tasks never do.

public ref class ConcurrentExclusiveSchedulerPair

public class ConcurrentExclusiveSchedulerPair

type ConcurrentExclusiveSchedulerPair = class

Public Class ConcurrentExclusiveSchedulerPair

Inheritance

Object

ConcurrentExclusiveSchedulerPair

Examples

The following example shows the use of the ConcurrentExclusiveSchedulerPair class. Readers run on the concurrent part of the scheduler. The writer runs on the exclusive part of the scheduler. This code example is part of a larger example provided for the How to: Specify a Task Scheduler in a Dataflow Block article.

// Create a ConcurrentExclusiveSchedulerPair object.
// Readers will run on the concurrent part of the scheduler pair.
// The writer will run on the exclusive part of the scheduler pair.
var taskSchedulerPair = new ConcurrentExclusiveSchedulerPair();

// Create an ActionBlock<int> object for each reader CheckBox object.
// Each ActionBlock<int> object represents an action that can read 
// from a resource in parallel to other readers.
// Specifying the concurrent part of the scheduler pair enables the 
// reader to run in parallel to other actions that are managed by 
// that scheduler.
var readerActions =
   from checkBox in new CheckBox[] { checkBox1, checkBox2, checkBox3 }
   select new ActionBlock<int>(milliseconds =>
   {
       // Toggle the check box to the checked state.
       toggleCheckBox.Post(checkBox);

       // Perform the read action. For demonstration, suspend the current
       // thread to simulate a lengthy read operation.
       Thread.Sleep(milliseconds);

       // Toggle the check box to the unchecked state.
       toggleCheckBox.Post(checkBox);
   },
   new ExecutionDataflowBlockOptions
   {
       TaskScheduler = taskSchedulerPair.ConcurrentScheduler
   });

// Create an ActionBlock<int> object for the writer CheckBox object.
// This ActionBlock<int> object represents an action that writes to 
// a resource, but cannot run in parallel to readers.
// Specifying the exclusive part of the scheduler pair enables the 
// writer to run in exclusively with respect to other actions that are 
// managed by the scheduler pair.
var writerAction = new ActionBlock<int>(milliseconds =>
{
    // Toggle the check box to the checked state.
    toggleCheckBox.Post(checkBox4);

    // Perform the write action. For demonstration, suspend the current
    // thread to simulate a lengthy write operation.
    Thread.Sleep(milliseconds);

    // Toggle the check box to the unchecked state.
    toggleCheckBox.Post(checkBox4);
},
new ExecutionDataflowBlockOptions
{
    TaskScheduler = taskSchedulerPair.ExclusiveScheduler
});

// Link the broadcaster to each reader and writer block.
// The BroadcastBlock<T> class propagates values that it 
// receives to all connected targets.
foreach (var readerAction in readerActions)
{
    broadcaster.LinkTo(readerAction);
}
broadcaster.LinkTo(writerAction);

' Create a ConcurrentExclusiveSchedulerPair object.
' Readers will run on the concurrent part of the scheduler pair.
' The writer will run on the exclusive part of the scheduler pair.
Dim taskSchedulerPair = New ConcurrentExclusiveSchedulerPair()

' Create an ActionBlock<int> object for each reader CheckBox object.
' Each ActionBlock<int> object represents an action that can read 
' from a resource in parallel to other readers.
' Specifying the concurrent part of the scheduler pair enables the 
' reader to run in parallel to other actions that are managed by 
' that scheduler.
Dim readerActions = From checkBox In New CheckBox() {checkBox1, checkBox2, checkBox3}
                    Select New ActionBlock(Of Integer)(Sub(milliseconds)
                                                           ' Toggle the check box to the checked state.
                                                           ' Perform the read action. For demonstration, suspend the current
                                                           ' thread to simulate a lengthy read operation.
                                                           ' Toggle the check box to the unchecked state.
                                                           toggleCheckBox.Post(checkBox)
                                                           Thread.Sleep(milliseconds)
                                                           toggleCheckBox.Post(checkBox)
                                                       End Sub, New ExecutionDataflowBlockOptions With {.TaskScheduler = taskSchedulerPair.ConcurrentScheduler})

' Create an ActionBlock<int> object for the writer CheckBox object.
' This ActionBlock<int> object represents an action that writes to 
' a resource, but cannot run in parallel to readers.
' Specifying the exclusive part of the scheduler pair enables the 
' writer to run in exclusively with respect to other actions that are 
' managed by the scheduler pair.
Dim writerAction = New ActionBlock(Of Integer)(Sub(milliseconds)
                                                   ' Toggle the check box to the checked state.
                                                   ' Perform the write action. For demonstration, suspend the current
                                                   ' thread to simulate a lengthy write operation.
                                                   ' Toggle the check box to the unchecked state.
                                                   toggleCheckBox.Post(checkBox4)
                                                   Thread.Sleep(milliseconds)
                                                   toggleCheckBox.Post(checkBox4)
                                               End Sub, New ExecutionDataflowBlockOptions With {.TaskScheduler = taskSchedulerPair.ExclusiveScheduler})

' Link the broadcaster to each reader and writer block.
' The BroadcastBlock<T> class propagates values that it 
' receives to all connected targets.
For Each readerAction In readerActions
    broadcaster.LinkTo(readerAction)
Next readerAction
broadcaster.LinkTo(writerAction)

Constructors

ConcurrentExclusiveSchedulerPair()	Initializes a new instance of the ConcurrentExclusiveSchedulerPair class.
ConcurrentExclusiveSchedulerPair(TaskScheduler)	Initializes a new instance of the ConcurrentExclusiveSchedulerPair class that targets the specified scheduler.
ConcurrentExclusiveSchedulerPair(TaskScheduler, Int32)	Initializes a new instance of the ConcurrentExclusiveSchedulerPair class that targets the specified scheduler with a maximum concurrency level.
ConcurrentExclusiveSchedulerPair(TaskScheduler, Int32, Int32)	Initializes a new instance of the ConcurrentExclusiveSchedulerPair class that targets the specified scheduler with a maximum concurrency level and a maximum number of scheduled tasks that may be processed as a unit.

Properties

Completion	Gets a Task that will complete when the scheduler has completed processing.
ConcurrentScheduler	Gets a TaskScheduler that can be used to schedule tasks to this pair that may run concurrently with other tasks on this pair.
ExclusiveScheduler	Gets a TaskScheduler that can be used to schedule tasks to this pair that must run exclusively with regards to other tasks on this pair.

Methods

Complete()	Informs the scheduler pair that it should not accept any more tasks.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)