Re: "Replace Temp with Query" use cases.

2009/11/7 mszerg <[email protected]>

>
>
> Hi All,
>
> First, I want to say that this is not a joke and kindly ask you to
> reply, suppose this will be simple and won't take much of your time :-)
>
> Recently I faced the following situation. In our project we have
> several functions with php code like this:
>
> // some global function
> function doSomethingWithX(X $x) {
> $x->getY()->setA(..);
> $x->getY()->setB(..);
> $x->getY()->setC(..);
> ...
> $x->getY()->setZ(..);
> }
>
> // this is how X looks like
> class X {
> private $y;
> // lazy getter of y
> function getY() {
> if (!$this->y) {
> $this->y = somehowCreateY();
> }
> return $this->y;
> }
> ...
> }
>
> During code review I suggested the following refactoring:
>
> function doSomethingWithX(X $x) {
> // store reference locally
> $y = $x->getY();
> // modify fields
> $y->setA(..);
> $y->setB(..);
> $y->setC(..);
> ...
> $y->setZ(..);
> }
>
> In my opinion it is just simpler, not saying 2x faster. But the authors
> say that "...according to Fowler's "Replace Temp with Query" refactoring
> strategy our version is better". From my conversations with the other
> colleagues, this looks like common approach. I suppose that this can be
> misunderstanding of the strategy use cases, but I may be wrong. Please,
> explain me what is right and wrong in this situation.
>

There is nothing definite about Fowlers patterns, they are just a catalogue
of "transformations" that may or may not add to the readability of a certain
piece of code.

As I read Fowlers book, he often usees "pattern pairs". That is one pattern
goes in one direction, the other in the opposite direction.  (so in you case
you should look for a pattern "replace query with temp variable"?).

When I look at your code, I get the feeling the function doSomethingWithX
ought to be a method of the class X. The reason being so many
getters/setters are used inside doSomethingWithX - that is a smell that the
algorithm should really be inside the class, since it 'know' so much about
X.



> --
> Thanks in advance,
> Serg Masyutin
>
>
> [Non-text portions of this message have been removed]
>
>  
>



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