communicate to it. The only function of the observer is to synchronize
its data with the subject when called. The key thing to understand about
the observer is that it does not use a polling process, which can be very
inefficient with a larger number of observers registered to a subject.
Updates are push only.Figure 2-6 Observer Pattern
The Observer pattern is often used to handle
communications between the model and the view in the
MVC pattern. Say, for example, that you have two
different views available to an end user. One view
provides a bar graph, and the other provides a scatter
plot. Both use the same data source from the model.
When that data changes or is updated, the two views
need to be updated. This is a perfect job for the Observer
pattern.
LINUX BASH
Knowing how to use Linux BASH is a necessary skill for
working with open-source technologies as well as many
of the tools you need to be proficient with to be
successful in the development world. Linux has taken
over the development world, and even Microsoft has
jumped into the game by providing the Windows
Subsystem for Linux for Windows 10 pro. For the
DEVASC exam, you need to know how to use BASH and
be familiar with some of the key commands.