Java Reference
In-Depth Information
the first time. For simplicity, this is thought to be done by the Distributor. After the AH instal-
lation has finished, it is launched, managing the installation of the application and then, in turn,
launching it. The AH will then take care of providing other deployment services to the applica-
tion while the latter is running. Services provided by the AH to the launched application could
be, for example, a just-in-time download of some needed resources, reporting logging activity
back to the Deployment Server, and so on.
T
IP
We are introducing an abstract model, so roles such as Distributor, Producer, and the
various phases may sound a bit intangible at first. We will see concrete examples
after the complete introduction of the model. Until that moment, you can think
about the real-world production scenario that you are more experienced with. For
example, in a medium-sized software house, the Producer and the Distributor could
be two colleagues working on the same project. You could think of a common
installer utility as an example of AH, a Web server that hosts some applet classes as a
Deployment Server, and so on.
Before digging into the main phases, let's review them in the following section:
Phase
Description
Development
The software to be deployed is released with the related
Deployment Policies for publication
Publication
At the end of this stage, the software is ready for end-user
installation
Deployment Server
Maintenance and management operations on Deployment
Management
Servers
Application Helper
The AH is installed for the first time on the client platform
Installation
Application Helper
The AH is launched
Execution
Application
Finally, the application is executed
Execution
Another important part of the model is the actors it defines. Let's intuitively recap the roles so
far. The next section will cover all of them in greater detail:
