DoubleCloud.org

I got a request a while back for extending the vSphere Java API. The idea is that the API itself is pretty basic and not high level enough for some applications. For example, if you want to add a virtual NIC to a virtual machine, there is no explicit method for doing this. Fair enough.

Now, how to achieve this?

Three possible approaches  Read more... (439 words, estimated 1:45 mins reading time)

1. Change the structure of the API. For every managed object type, we have two types: one with implementation, and the other inheriting the first one but really empty. The user can replace the first second one with extra methods as extensions. This approach is smart, but will cause confusion in the future. For instance, we will have many different implementations for the sample types.
2. Use composition. You can create a new type that contains an instance of a managed object. How to expose the methods of the managed object? You can either manually add them to the containing type, or expose the instance of the managed object so that others can call its methods.
3. Use inheritance. You can create a new type that inherits a managed object type. Once you get an instance of a normal managed object, you can pass into the constructor of extended managed object type. You can use the extended type anywhere a normal type is expected. Let’s pick VirtualMachine as an example,