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1
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So if you follow my class so far, you know that
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I like to give a little bit of history when I talk
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about a specific topic. So I'm going to do the same also
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in this case for refactoring. I'm going to start by mentioning, the fact
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that refactoring is something that programmers have always done. I gave
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you a trivial example just a minute ago of what refactoring is.
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So even more complicated refactorings are
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something that are commonplace for developers.
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Somehow refactoring is especially important in
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the context of object-oriented languages and
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probably it's because the object-oriented features are well suited to
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make designs flexible and reusable. Because of the fact that help
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encapsulation, information hiding, and so they make it easier to
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modify something without changing the functionality that it provides to the
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outside world. However, you should keep in mind that refactoring
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is really not specific to object oriented languages, you can also
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refactor other languages, it's just more common to see it in
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that context. So one of the first examples of a specific
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discussion of what the refactorings are is Opdyke's PhD
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thesis in 1990. Which discusses refactorings for small talk.
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And some of you might be familiar with small
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talk, which is a specific objectory language. And in
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more recent times, refactoring's becoming increasing popular due to
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lightweight development methodoogies, due to agile development, which is
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something that we just discussed in this class. For
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example, when we talked about extreme programming, we mentioned refactoring
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a few times. And the reason why its so popular
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is because re-factoring is one of the practices that help.
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Making changes less expensive. And therefore adapt to changing requirements
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and changing environments more quickly.
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And continuing with historical perspective, one
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of the milestones in the history of re-factoring [INAUDIBLE] is
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a book by Martin Fowler. This is a book entitled
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Improving the Design of Existing [INAUDIBLE]. And it contains a
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catalog of refactorings, a list of bad smells, in code, and
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we're going to see what that mean exactly. Nothing to
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do with other kinds of bad smells. It talks about
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guidelines on when to apply refactoring. And finally, which is
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very useful, it provides example of code, before and after.
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Applying the refactoring and we're going to use more of the
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same style when discussing refactoring in the rest of this
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lesson. More specifically what we're discussing next, are some examples
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of refactoring and also some examples of code bad smells.
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