I'm a fresh man to OMG DDS and I tried to run the example GreetingPublishingApp. I don't know what should I do.
DomainParticipantFactory factory =
DomainParticipantFactory.getInstance(Bootstrap.createInstance());
DomainParticipant dp = factory.createParticipant();
It looks like you are trying to use the new Java5 API, which is still in-progress. The API alone will not help as it is just a facade to an underlying implementation. As far as I know no current implementations support the new API, as it is not yet finished.
Regarding the error message: the intent is to put the class of the concrete implementation into the org.omg.dds.serviceClassName system property.
Related
I google this topic but I couldn't find the proper answer. I understand API as only Interface class that referencing library files to be used by other applications from other platforms. But someone told me that APIs are library files themselves.
I'm a novice to this topic so that suggest any answers to me, please.
In my opinion, an API is just a collection of interfaces. It is independent from implementation. Of course, usually, a standard implementation exists and is "associated" with the API but if the implementation is linked to the API, the API is not linked to the implementation.
If you take the example of Java, you'll notice that the API ( http://docs.oracle.com/javase/7/docs/api/ ) only show protected and public fields/constructors/methods/... It is not showing private stuff.
The API is reduced to what is visible for the user which is somehow the definition of an interface. The implementation is hidden.
What might be confusing is that the API is generated from the implementation but that doesn't mean that the API is the implementation.
I might be wrong but I think things are usually going like this:
An private API is defined (it is specification, so, it can be source code or any descriptive file)
An implementation is developed based on the private API
A public API is generated from this implementation and is published
The implementation is published as a Framework / Toolbox / or whatever the name
Developers use the public API to build their application and they choose the best implementation (which is generally the one from which it was generated).
Fell free to comment if you disagree ;)
I'm engaged in building NServiceBus Gateway handler, and I need to avoid config files so that all configuration is defined inside c# classes. As a result I have to convert the following section to c# code
<GatewayConfig>
<Channels>
<Channel Address="http://localhost:25899/SiteB/" ChannelType="Http" Default="true"/>
</Channels>
</GatewayConfig>
I've found GatewayConfig, ChannelCollection and ChannelConfig in a NServiceBus.Config namespace, but I can not link them together, coz GatewayConfig refers to ChannelCollection, but ChannelCollection has nothing to do with ChannelConfig. Please help
Just create a class implementing IProvideConfiguration of GatewayConfig. That gives you a way to provide your own config. Look at the pubsub sample for the exact details on how to do this.
Well, I've found the way to do it as I installed Reflector and looked into the implementation. There is a ChannelCollection.CreateNewElement() method returning back System.Configuration.ConfigurationElement. NServiceBus overriden the method instantiating ChannelConfig inside it, so all I have to do is to cast ConfigurationElement type to ChannelConfig type which is far from intuitive interface. Looks like this NServiceBus.Config.ChannelCollection is kind of unfinished work, because if you look at other collections like NServiceBus.Config.MessageEndpointMappingCollection you can find there all necessary type-safe methods to work with its child elements NServiceBus.Config.MessageEndpointMapping, so I think NServiceBus team was just lazy to make the same for ChannelCollection.
UPDATE: as CreateNewElement() method is protected, I have to implement my own class inherited from ChannelCollection to make a method adding new ChannelConfig element publicly available
I recently moved to using the binary serializer to send messages with NServiceBus. My messages are all defined as interfaces and are instantiated using
bus.Send<MessageType>(msg => msg.Property = someValue)
This leads to an exception being thrown from NServiceBus stating that
Cannot create an instance of an
interface
I can see from the stack trace that the SimpleMessageMapper is being used, and after looking in the source can see it's making a call to Activator.CreateInstance.
I can't find anything in the documentation stating that it's not possible to do what I'm trying to do, is there a way to fix this?
Thanks,
Matt
I only just started playing with nServiceBus, so all I can offer you is theory :).
Are you defining the implementation classes for your message interfaces, or is nServiceBus generating classes on its own? If the former, make sure you still have a default constructor and that the class and all fields/events are marked as [Serializable] or [NonSerialized]. If the latter, it's possible that nServiceBus doesn't know how to generate members which may be needed for (de)serialization. You may have to write and map the implementation class yourself.
I am looking for "typical" way one navigates MSDN to get a COM class to do what they want.
Example problem: I am looking for an API way to unblock a local file (remove internet zone/mark of the web from a file programmatically).
I found one post on stackoverflow.com that talked about clsid_persistentzoneidentifier. so i searched in MSDN and got to http://msdn.microsoft.com/en-us/library/ms537029(VS.85).aspx. What I am looking for,is what one does after they get to this url. From this location, I am not able to figure what the sequence of operations should be. How do I connect this IZoneIdentifier to IPersistFile? etc. There must be something basic that I am missing wrt COM related documentation. MSDN has interfaces and objects, but nothing that helps me visualize a "sequence" diagram of sorts. Nothing that will get me to understand which COM objects are from same class. hence can/or should be QueryInterfaced, adn which should be CoCreated.
The documentation for that indicates a few things.
The first is that you can call CoCreateInstance, passing CLSID_PersistentZoneIdentifier to get an implementation of these two interfaces:
IPersistFile
IZoneIdentifier
It also says:
Use IPersistFile to attach the object
to the target file and IZoneIdentifier
to examine or to manipulate the zone
ID.
That being said, you can look at the documentation for IPersistFile here:
http://msdn.microsoft.com/en-us/library/ms687223(VS.85).aspx
It shows that there is a Load method, which is what you want to call with the filename to load the implementation with details about the file.
From there, you can call QueryInterface on the IUnknown interface implementation to get the IZoneIdentifier interface and then call the Remove method on it to set the zone to the local machine.
For that purpose, if it's not obvious from the documentation, I like to find sample programs in which relevent APIs are used: either using Google, or perhaps from whichever of the Microsoft SDKs is relevent.
Microsoft SDKs, for example this one, include sample programs.
To implement "method-missing"-semantics and such in C# 4.0, you have to implement IDynamicObject:
public interface IDynamicObject
{
MetaObject GetMetaObject(Expression parameter);
}
As far as I can figure out IDynamicObject is actually part of the DLR, so it is not new. But I have not been able to find much documentation on it.
There are some very simple example implementations out there (f.x. here and here), but could anyone point me to more complete implementations or some real documentation?
Especially, how exactly are you supposed to handle the "parameter"-parameter?
The short answer is that the MetaObject is what's responsible for actually generating the code that will be run at the call site. The mechanism that it uses for this is LINQ expression trees, which have been enhanced in the DLR. So instead of starting with an object, it starts with an expression that represents the object, and ultimately it's going to need to return an expression tree that describes the action to be taken.
When playing with this, please remember that the version of System.Core in the CTP was taken from a snapshot at the end of August. It doesn't correspond very cleanly to any particular beta of IronPython. A number of changes have been made to the DLR since then.
Also, for compatibility with the CLR v2 System.Core, releases of IronPython starting with either beta 4 or beta 5 now rename everything in that's in the System namespace to be in the Microsoft namespace instead.
If you want an end to end sample including source code, resulting in a dynamic object that stores value for arbitrary properties in a Dictionary then my post "A first look at Duck Typing in C# 4.0" could be right for you. I wrote that post to show how dynamic object can be cast to statically typed interfaces. It has a complete working implementation of a Duck that is a IDynamicObject and may acts like a IQuack.
If you need more information contact me on my blog and I will help you along, as good as I can.
I just blogged about how to do this here:
http://mikehadlow.blogspot.com/2008/10/dynamic-dispatch-in-c-40.html
Here is what I have figured out so far:
The Dynamic Language Runtime is currently maintained as part of the IronPython project. So that is the best place to go for information.
The easiest way to implement a class supporting IDynamicObject seems to be to derive from Microsoft.Scripting.Actions.Dynamic and override the relevant methods, for instance the Call-method to implement function call semantics. It looks like Microsoft.Scripting.Actions.Dynamic hasn't been included in the CTP, but the one from IronPython 2.0 looks like it will work.
I am still unclear on the exact meaning of the "parameter"-parameter, but it seems to provide context for the binding of the dynamic-object.
This presentation also provides a lot of information about the DLR:
Deep Dive: Dynamic Languages in Microsoft .NET by Jim Hugunin.