ConcurrencyMode Sabit listesi

Tanım

public enum class ConcurrencyMode

public enum ConcurrencyMode

type ConcurrencyMode = 

Public Enum ConcurrencyMode

Devralma

Object

ValueType

Enum

ConcurrencyMode

Alanlar

Örnekler

Aşağıdaki kod örneği Single, Reentrant ve Multiple kullanma arasındaki farkı gösterir. Bu örnek arkasında gerçek bir uygulama olmadan derlenmez, ancak WCF'nin yaptığı iş parçacığı oluşturma garantilerinin türünü ve bunun işlem kodunuz için ne anlama geldiğini gösterir.

using System;
using System.ServiceModel;

[ServiceContract]
public interface IHttpFetcher
{
  [OperationContract]
  string GetWebPage(string address);
}

// These classes have the invariant that:
//     this.slow.GetWebPage(this.cachedAddress) == this.cachedWebPage.
// When you read cached values you can assume they are valid. When
// you write the cached values, you must guarantee that they are valid.
// With ConcurrencyMode.Single, WCF does not call again into the object
// so long as the method is running. After the operation returns the object
// can be called again, so you must make sure state is consistent before
// returning.
[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Single)]
class SingleCachingHttpFetcher : IHttpFetcher
{
    string cachedWebPage;
    string cachedAddress;
    readonly IHttpFetcher slow;

    public string GetWebPage(string address)
    {
        // <-- Can assume cache is valid.
        if (this.cachedAddress == address)
        {
            return this.cachedWebPage;
        }

        // <-- Cache is no longer valid because we are changing
        // one of the values.
        this.cachedAddress = address;
        string webPage = slow.GetWebPage(address);
        this.cachedWebPage = webPage;
        // <-- Cache is valid again here.

        return this.cachedWebPage;
        // <-- Must guarantee that the cache is valid because we are returning.
    }
}

// With ConcurrencyMode.Reentrant, WCF makes sure that only one
// thread runs in your code at a time. However, when you call out on a
// channel, the operation can get called again on another thread. Therefore
// you must confirm that state is consistent both before channel calls and
// before you return.
[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Reentrant)]
class ReentrantCachingHttpFetcher : IHttpFetcher
{
  string cachedWebPage;
  string cachedAddress;
  readonly SlowHttpFetcher slow;

  public ReentrantCachingHttpFetcher()
  {
    this.slow = new SlowHttpFetcher();
  }

  public string GetWebPage(string address)
  {
    // <-- Can assume that cache is valid.
    if (this.cachedAddress == address)
    {
        return this.cachedWebPage;
    }

    // <-- Must guarantee that the cache is valid, because
    // the operation can be called again before we return.
    string webPage = slow.GetWebPage(address);
    // <-- Can assume cache is valid.

    // <-- Cache is no longer valid because we are changing
    // one of the values.
    this.cachedAddress = address;
    this.cachedWebPage = webPage;
    // <-- Cache is valid again here.

    return this.cachedWebPage;
    // <-- Must guarantee that cache is valid because we are returning.
  }
}

// With ConcurrencyMode.Multiple, threads can call an operation at any time.
// It is your responsibility to guard your state with locks. If
// you always guarantee you leave state consistent when you leave
// the lock, you can assume it is valid when you enter the lock.
[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple)]
class MultipleCachingHttpFetcher : IHttpFetcher
{
  string cachedWebPage;
  string cachedAddress;
  readonly SlowHttpFetcher slow;
  readonly object ThisLock = new object();

  public MultipleCachingHttpFetcher()
  {
    this.slow = new SlowHttpFetcher();
  }

  public string GetWebPage(string address)
  {
    lock (this.ThisLock)
    {
      // <-- Can assume cache is valid.
      if (this.cachedAddress == address)
      {
          return this.cachedWebPage;
          // <-- Must guarantee that cache is valid because
          // the operation returns and releases the lock.
      }
      // <-- Must guarantee that cache is valid here because
      // the operation releases the lock.
    }

    string webPage = slow.GetWebPage(address);

    lock (this.ThisLock)
    {
      // <-- Can assume cache is valid.

      // <-- Cache is no longer valid because the operation
      // changes one of the values.
      this.cachedAddress = address;
      this.cachedWebPage = webPage;
      // <-- Cache is valid again here.

      // <-- Must guarantee that cache is valid because
      // the operation releases the lock.
    }

    return webPage;
  }
}

Açıklamalar

ConcurrencyMode , bir hizmet sınıfının tek iş parçacıklı veya çok iş parçacıklı işlem modlarını destekleyip desteklemediğini belirtmek için özelliğiyle ConcurrencyMode birlikte kullanılır. Tek iş parçacıklı bir işlem yeniden girdi veya yeniden değil olabilir.

Aşağıdaki tabloda, Windows Communication Foundation'ın (WCF) işlemine bağlı olarak başka bir işlem devam ederken çağrılmaya izin verme durumu ConcurrencyModegösterilmektedir.

Şunlara uygulanır