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The beauty of objects is that you can use
them even if you don't know how they work inside. As we said
before, objects are "little black boxes of functionality". So
what does that mean exactly?
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A black box is an
engineering term that works like this. First we drop something
in to a black box. Then, we wait while our thing is "magically transformed"
inside the black box. Finally, we receive a new transformed thing back from
the black box. The beauty of a black box is that all we need to
know is how to drop something into the black box and what to
expect on the other side. We do not need to understand the magic
inside. |
Well, that means that nobody but the
object itself needs to know anything about how its properties and
methods are defined and implemented.
Are the list of items stored in an array
or a vector? How is sorting handled, with a quick sort or a
bubble sort? How is a selection marked and how do you handle
multiple selections?
Encapsulation means that the answers to
all these questions are private, known only by the object
itself.
What is the benefit of this?
Well, the benefit is that if I want to
use a Select Box, I do not need to deal with all of the complex
code that handles all of the functionality of a select box.
Instead, I just put the self-contained select box object in my application
and use it.
This is an incredibly useful concept
because it means that it is far easier to modify and understand
code because you only need to deal with small pieces of code at
any one time. As a developer, I do not need to deal with the
intricacies of select box functionality, I just use the thing!
It is also a good metaphor for the real
world, that can be thought of as being made up of encapsulated
objects.
Consider the computer you are using to
read this. Do you know how the CPU works? Most likely you
don't. But that is fine. It works regardless. And the fact
that you don't have to spend time learning electrical engineering
means that you are free to spend your time building things "using"
the CPU.
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