Design Pattern & Software Design (2/4 14th Sep 2010)

About Design Decision

1.DRY
DRY means Don't repeat yourself
We should not duplicated design

2.keep it simple
The design should be clear and easy to see.
Do not be complex.

3.Loose coupling
This means even if we change one component, the system can work.
That component is loose coupling, so loose coupling means it can be fexible.

4.Separating things that change
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Software should be extensible and flexible, because we may need some changes for the software.
If the component is neither extensible nor flexible, we cannot fix the system when it has some wrong.

Extensible is to add something.
Flexible is to be able to put out and change something.