我有一个具有以下结构的奥尔良应用程序:
public interface IGraintest : Orleans.IGrainWithGuidCompoundKey
{
Task Init();
}
public abstract class GraintestImpl<T> : Grain, IGraintest, Deserializer<T>
{
string streamName;
public Task Init()
{
return Task.CompletedTask;
}
public override async Task OnActivateAsync()
{
var primaryKey = this.GetPrimaryKey(out streamName);
var streamProvider = GetStreamProvider("SMSProvider");
var stream = streamProvider.GetStream<String>(primaryKey, streamName);
// To resume stream in case of stream deactivation
var subscriptionHandles = await stream.GetAllSubscriptionHandles();
if (subscriptionHandles.Count > 0)
{
foreach (var subscriptionHandle in subscriptionHandles)
{
await subscriptionHandle.ResumeAsync(OnNextMessage);
}
}
await stream.SubscribeAsync(OnNextMessage);
}
public abstract T Process(string l);
private Task OnNextMessage(string message, StreamSequenceToken sequenceToken)
{
T obj = Process(message);
//gonna do something with obj here
return Task.CompletedTask;
}
}
public class ProcessImplA: GraintestImpl<Car>
{
public override Car Process(string l)
{
return new Car(l);
}
}
public class ProcessImplB: GraintestImpl<Boat>
{
public override Boat Process(string l)
{
return new Boat(l);
}
}
这里我有一个粒,可用来从流中读取消息并对其进行一些操作。由于我具有不同的对象类型,因此我想与之一起创建一个抽象类来实现该接口。问题出在这里:
var sourceOne = client.GetGrain<IGraintest>(guid, "Car");
var sourceTwo = client.GetGrain<IGraintest>(guid, "Boat");
当我这样运行程序时,出现错误代码:
Exception while trying to run client: Cannot resolve grain interface ID=-<blabla> to a grain class because of multiple implementations of it
所以我的问题是,我是否可以做一个小小的改动以完成这项工作,还是必须为我要使用的每个ProcessImpl晶粒创建一个晶粒接口?
您可以通过使用接受晶粒类名称前缀的重载来消除GetGrain
调用的歧义。
var sourceOne = client.GetGrain<IGraintest>(guid, "Car", grainClassNamePrefix: "MyNamespace.ProcessImplA");
var sourceTwo = client.GetGrain<IGraintest>(guid, "Boat", grainClassNamePrefix: "MyNamespace.ProcessImplB");
否则,如果有两种接口实现,那么运行时将不知道如何决定使用哪种接口。重要的是,对于您的情况,IGrainFactory
实现未知有关哪个类实现哪个构造的通用接口的信息,因此无法选择实现。
另一种方法是将标记界面添加到您的谷物类中,例如,您可以使用IGrainTestImplBoat
:
public interface IGrainTestImplBoat : Orleans.IGrainWithGuidCompoundKey { }
public class ProcessImplB : GraintestImpl<Boat>, IGrainTestImplBoat { /* ... */ }
var sourceTwo = client.GetGrain<IGrainTestImplBoat>(guid, "Boat");