Vision: a distributed presentation framework.
Vision is a proof of concept application (thanks aseigo for the initial suggestion), showing what can be easily obtained by using the service-oriented paradigm together with rich client applications.
What is Vision?
But, more importantly: what's a distributed presentation?
Imagine that you are showing a presentation, and that someone wants to see what you're presenting... in his computer! To do so, he should connect in some way to your presentation. Whenever you change page (or make another relevant action, like changing document), the client should be notified and synchronized automagically.
That is exactly what Vision does. It forms a network between the presenter and the clients, keeping the clients synchronized with the presentation.
A screencast is better than a thousand words: an example usage of vision with the previewer plasmoid and kpdf.
As you can see in the screencast, Vision already supports more than one viewer (there are shown kpdf and the previewer plasmoid, but we also already support okular).
Another nice feature of Vision is that it forms a P2P network. A client acts also as a presentation server. Say that A is watching B's presentation. Now another client (C) can connect to A. Whenever A receives an event from B, it will now also send it to C.
This can be exploited, for example, in order to perform bandwidth load balancing.
Note also that Vision makes use of SODEP, a binary protocol especially designed for service communications (it can, nevertheless, use all of the other JOLIE supported protocols, such as SOAP, HTTP, GWT-RPC...). Thus, the needed bandwidth is very small and the application can handle a lot of clients at the same time.
Exposing Vision to other platforms
A great feature of JOLIE is that it separates the logical interfaces of a service from their deployment. Suppose that we want to extend Vision to support Bluetooth clients. The ideal solution would be to expose the same interface that we expose on the network via sockets to bluetooth. Luckily, doing that in JOLIE is very easy:
What do these lines mean?
Well, they're telling JOLIE to expose the
Guess what? It just works! (video) And what's better than a mobile phone to test it?
By the way:
just in case you want to see more service-oriented goodness in KDE. =)
What is Vision?
But, more importantly: what's a distributed presentation?
Imagine that you are showing a presentation, and that someone wants to see what you're presenting... in his computer! To do so, he should connect in some way to your presentation. Whenever you change page (or make another relevant action, like changing document), the client should be notified and synchronized automagically.
That is exactly what Vision does. It forms a network between the presenter and the clients, keeping the clients synchronized with the presentation.
A screencast is better than a thousand words: an example usage of vision with the previewer plasmoid and kpdf.
As you can see in the screencast, Vision already supports more than one viewer (there are shown kpdf and the previewer plasmoid, but we also already support okular).
Another nice feature of Vision is that it forms a P2P network. A client acts also as a presentation server. Say that A is watching B's presentation. Now another client (C) can connect to A. Whenever A receives an event from B, it will now also send it to C.
This can be exploited, for example, in order to perform bandwidth load balancing.
Note also that Vision makes use of SODEP, a binary protocol especially designed for service communications (it can, nevertheless, use all of the other JOLIE supported protocols, such as SOAP, HTTP, GWT-RPC...). Thus, the needed bandwidth is very small and the application can handle a lot of clients at the same time.
Exposing Vision to other platforms
A great feature of JOLIE is that it separates the logical interfaces of a service from their deployment. Suppose that we want to extend Vision to support Bluetooth clients. The ideal solution would be to expose the same interface that we expose on the network via sockets to bluetooth. Luckily, doing that in JOLIE is very easy:
service PresenterBluetoothService
{
Location: "btl2cap://localhost:3B9FA89520078C303355AAA694238F07;name=Vision;encrypt=false;authenticate=false"
Protocol: sodep { .charset = "ISO8859-1"; .keepAlive = 1 }
Ports: PresenterInputPort
}
What do these lines mean?
Well, they're telling JOLIE to expose the
PresenterInputPort interface (which is the Vision presenter interface) on the pointed bluetooth Location using the SODEP protocol to encode and decode data. You can see the whole presenter service code in the JOLIE SVN repository (/trunk/playground/vision).Guess what? It just works! (video) And what's better than a mobile phone to test it?
By the way:
just in case you want to see more service-oriented goodness in KDE. =)