Re: Dependency Injection vs. Global/Static data

"Alf P. Steinbach /Usenet" <>
Thu, 02 Sep 2010 10:27:40 +0200
* thomas, on 02.09.2010 10:14:

class Util{
     void print(){...}

class Work{
     void SetUtil(Util* pUtil){m_pUtil = pUtil;}
     Util* m_pUtil;

class Util{
     static void print(){...}
What's the advantages/disadvantages when comparing these two methods?

There is no polymorphism for either design.

In the first example you have the option of turning off and on printing. This
could much more easily be accomplished via a boolean member in 'Work' + an
internal print method that checks the boolean.

If you meant for 'print' to be virtual, then the first example offers the
additional functionality of customizing the effect of 'print'.

Presumably you know that, and whatever advantage depends on your requirements,
which you fail to state here. However, if the second example is a possible
solution for your requirements, then there is no current advantage, only a
possible future advantage. And in that case it's purely a methodology question,
"Should one design for possible future requirements?", and off-topic here.

C++ aspect: for the second example, use a namespace, not a class.

When I use these two methods in dll interface(Work class inside dll;
Util may be used by several modules.), anything I need to take special
care of?

That's a Windows question, not a C++ question.

Cheers & hth.,

- Alf

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