I have a stream onto which serialized objects representing messages are dumped periodically. The objects are one of a very limited number of types, and other than the actual sequence of bytes that arrives, I have no way of knowing what type of message it is.
I would like to simply try to deserialize it as an object of a particular type, and if an exception is thrown, try again with the next type.
I have an interface that looks like this:
public interface IMessageHandler<T> where T : class, IMessage {
T Handle(string message);
}
// elsewhere:
// (These are all xsd.exe-generated classes from an XML schema.)
public class AppleMessage : IMessage { ... }
public class BananaMessage : IMessage { ... }
public class CoconutMessage : IMessage { ... }
Then I wrote a GenericHandler<T> that looks like this:
public class GenericHandler<T> : IMessageHandler<T> where T: class, IMessage {
public class MessageHandler : IMessageHandler {
T IMessageHandler.Handle(string message) {
T result = default(T);
try {
// This utility method tries to deserialize the object with an
// XmlSerializer as if it were an object of type T.
result = Utils.SerializationHelper.Deserialize<T>(message);
} catch (InvalidCastException e) {
result = default(T);
}
return result;
}
}
}
Two questions:
Using my GenericHandler<T> (or something similar to it), I'd now like to populate a collection with handlers that each handle a different type. Then I want to invoke each handler's Handle method on a particular message to see if it can be deserialized. If I get a null result, move onto the next handler; otherwise, the message has been deserialized. Can this be done?
Is there a better way to deserialize data of unknown (but restricted) type?
