Java Reference
In-Depth Information
The Resolution Phase can be performed on the server or by the AH itself. It is not required to
be carried out right after the AH connects back to the server. Nevertheless, for simplicity, we
will report this phase right after the AH connection with its Deployment Server. Of course, the
AH could even avoid connecting back to the server all the time, or it cannot, because the client
platform is currently offline, and so on.
The very idea of a Resolution Phase is quite theoretical. We will see this phase in detail in the
next section.
2
C
AUTION
There is an important difference between the “Application Update” and “On-The-
Run Application Update” phases, in that the first is a very basic stage provided by all
the AHs, basically consisting of file replacement on the local client platform. In the
second case, the AH must be able to replace pieces of the application while this one
is running, without damaging its operation.
Finally, we are now ready to take a look at the complete deployment model, as shown in Figure
2.5.
Practicing with the Model
It's time to begin to use our model, beginning with some easy and familiar cases. Note that the
phases we discussed can also be viewed as
features
a given deployment solution might provide.
From this perspective, we can compare different deployment technologies based on the deploy-
ment features they provide.
A Well-Known First Example
Let's take a look at a well-known case: the typical installer utility, described through our
deployment model. We discussed it before, but we need to be more precise, and can compare it
with other deployment technologies. Figure 2.6 illustrates the model instance in this situation.
From Figure 2.6, we can grasp the difference between this deployment means and other more
articulated deployment solutions. Note that, for example, the Resolution Phase is very limited,
because the AH (the installer utility) can only install the application or run it before exiting.
Also interesting to see is the Distribution-To-User Publication Phase. Here, it consists of pack-
aging the resources into the installer bundle according to the given client platform, and leaving
the obtained executable available for downloads or other forms of delivery.
