Code RefactoringPresented by Steven

Dec. 2016

Why

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FastRunnable

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FastRunnable

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Spaghetti Code

● program flow is conceptually like a bowl of spaghetti, i.e. twisted and tangled.

● complex and confusing control structures that are barely understandable

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What

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● Code refactoring is the process of restructuring existing computer code without changing its external behaviour.

Code Refactoring

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在不改變軟體的外在行為下，改善既有軟體的內部設計。

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2 Advantages

6 Techniques

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Advantages

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Expressiveness

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Expressiveness

Complexity

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Expressiveness

Complexity

Readability

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Expressiveness

Complexity

Readability

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Maintainability

Expressiveness

Complexity

Readability

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Maintainability

Expressiveness

Complexity

Readability

Extensibility

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Maintainability Extensibility

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Techniques

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Generalization ExtractionEncapsulation

Pulling-up Pushing-downRenaming

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Generalization ExtractionEncapsulation

Pulling-up Pushing-downRenamingcommon: private / (default) / protected / public

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Generalization ExtractionEncapsulation

Pulling-up Pushing-downRenamingcreate more general types, e.g., super-classes

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Generalization ExtractionEncapsulation

Pulling-up Pushing-downRenamingextract {classes, methods, funcions}fewer methods → clearer purpose and functionality

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Generalization ExtractionEncapsulation

Pulling-up Pushing-downRenaming

rename {methods, fields}

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Generalization ExtractionEncapsulation

Pulling-up Pushing-downRenaming

moving methods between parent/child classes

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Generalization ExtractionEncapsulation

Pulling-up Pushing-downRenaming

http://refactoring.com/catalog/index.html29

How

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Encapsulation 31

Encapsulation 32

data / field → private

Setter & Getter

Encapsulation 33

Generalization 34

Generalization 35

Generalization 36

Generalization 37

Generalization 38

Renaming 39

Renaming 40

Conclusion

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● what

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● whatMaintainability

Extensibility43

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