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Update readme with visitor description

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Petrutiu Mihai
2016-07-13 17:33:58 +03:00
parent 689509c5de
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README.md
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@@ -375,16 +375,23 @@ Template pattern works using 'the Hollywood principle' from the base class point
* Visitor is similar to Iterator, the difference is that visitor pattern allows to process more complex structure with different types * Visitor is similar to Iterator, the difference is that visitor pattern allows to process more complex structure with different types
### b. When to use Visitor pattern ### b. When to use Visitor pattern
* When you have a complex structure that doesn't change that much, but you need to add more types of processing * Dynamic flavor: When you have a complex structure that doesn't change that much, but you need to add more types of processing
### c. Actors ### c. Actors
* Visitor - The interface that defines methods to visit each of the visitable types * Visitor - The interface that defines methods to visit each of the visitable types
* Concrete Visitor - Implemementation of the Visitor pattern * Concrete Visitor - Implemementation of the Visitor pattern
* Visitable - interface that accepts the visitor, usually one method->Accept(Visitor v) * Visitable - interface that accepts the visitor, usually one method->Accept(Visitor v)
* Concrete Visitable - Objects that are part of the complex structure that needs to be visited * Concrete Visitable - Objects that are part of the complex structure that needs to be visited
* Object Structure - Object that contains all the visitable objects, and defines a way to visit them * Object Structure - Object that contains all the visitable objects, and defines a way to visit them
### d. Pitfalls ### d. Pitfalls
* Every time you add a new visitable object, you need to modify all the visitors. * Every time you add a new visitable object, you need to modify all the visitors.
### e. Flavors ### e. Flavors
* In languages like C#, instead of having all the Concrete Visitable implemement the Visitable, we could use
### f. Examples ### f. Examples
* Calculate money of corruption subject: Starting class: CalculateMoney.WithVisitor.CalaculateMoneyWithVisitorExample
* For a corruption suspect calculate Monthly income, and the net worth using 2 different varations
* Motivational example: Starting class: CalculateMoney.WithoutVisitor.CalculateMoneyMotivationalExample
* Same functionality, but using dynamic flavor: The Visitable interface is used only for marker. And the Object Structure uses dynamic to invoke the visitors.