Replace Parameter with Explicit Methods

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(New page: == Motivation == ''Refactoring'' Martin Fowler 1999 states that: "If a method can get a value that is passed in as a parameter by another means, it should." == Example == An object ...)
 
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== Motivation ==
 
  
''Refactoring'' [[Martin Fowler 1999]] states that: "If a method can get a value that is passed in as a parameter by another means, it should."
 
 
== Example ==
 
 
An object invokes a method, then passes the result as a parameter for a method. The receiver can also invoke this method. So the best idea is to remove the parameter and let the receiver invoke the method.
 
 
int basePrice = quantity * itemPrice;
 
discountLevel = getDiscountLevel();
 
double finalPrice = discountedPrice(basePrice, discountLevel);
 
 
Above we have some code, but lets remove the discountLevel parameter from discountedPrice(basePrice, discountLevel). Now we have:
 
 
int basePrice = quantity * itemPrice;
 
double finalPrice = discountedPrice(basePrice);
 
 
The discountedPrice(basePrice) method now looks like:
 
 
discountedPrice(basePrice)
 
{
 
    int discountLevel = getDiscountLevel();
 
    //does calculation type stuff here
 
   
 
    return discountedPrice;
 
}
 

Revision as of 13:08, 23 September 2008

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