Visitor and Stratergy Pattern

[C#]

Dear Freinds,

I was going through Stratergy and Visitor patterns. I am really
confused. Both look same passing the logic object in to the a business
object and the logic object works on the business object.

Please clarify.

Regards,
Design Pattern Learner

http://www.questpond.com/FreeDesign1.htm

[Peter Morris]

Re: Visitor and Stratergy Pattern

StrategyPattern is a way of saying you want something done in a flexible
way. For example a package transport company might charge its customers a
basic rate based on size and weight of the package, but for larger and more
regular customers they may have a different approach completely that
requires custom code.

A visitor pattern is something else completely. If you often find yourself
writing code like this on the same structure....

foreach (CustomerSite site in Customer.Sites)
foreach (VendingLocatio n location in site.VendingLoc ations)
foreach (VendingMachine machine in location.Vendin gMachines)

Then you might want to consider using a VisitorPattern. The pattern
basically does the looping for you and executes a method for each item. The
benefit being that if ever you add a new level to the loop you would then
add a new method to the callback interface, the compile will then fail
everywhere you haven't handled the new loop level because the called back
class has not implemented the method.

The visitor pattern is also useful when some of your members are private.


Pete

[JackPot]

Re: Visitor and Stratergy Pattern

Hey Peter, are you going to get a cut of the $120 this dude is demanding for
his video series he is building using guys like you to teach him free what
he is putting into his product and selling?

I'm certainly a business-minded developer myself and I've developed revenue
share services and would at the very least give named attribution to those
who have mentored me as I learn so I was just wondering...


"Peter Morris" <mrpmorrisNO@SP AMgmail.comwrot e in message
news:OIZZ$uy8IH A.2332@TK2MSFTN GP03.phx.gbl...

StrategyPattern is a way of saying you want something done in a flexible
way. For example a package transport company might charge its customers a
basic rate based on size and weight of the package, but for larger and
more regular customers they may have a different approach completely that
requires custom code.
>
A visitor pattern is something else completely. If you often find
yourself writing code like this on the same structure....
>
foreach (CustomerSite site in Customer.Sites)
foreach (VendingLocatio n location in site.VendingLoc ations)
foreach (VendingMachine machine in location.Vendin gMachines)
>
Then you might want to consider using a VisitorPattern. The pattern
basically does the looping for you and executes a method for each item.
The benefit being that if ever you add a new level to the loop you would
then add a new method to the callback interface, the compile will then
fail everywhere you haven't handled the new loop level because the called
back class has not implemented the method.
>
The visitor pattern is also useful when some of your members are private.
>
>
Pete

[Peter Morris]

Re: Visitor and Stratergy Pattern

Hey Peter, are you going to get a cut of the $120 this dude is demanding

for his video series he is building using guys like you to teach him free
what he is putting into his product and selling?
>
I'm certainly a business-minded developer myself and I've developed
revenue share services and would at the very least give named attribution
to those who have mentored me as I learn so I was just wondering...

I didn't follow the link at the bottom of the post. I assumed it was the
site he couldn't understand but it seems you are correct. In honest I am
not sure how to feel about it, probably everyone here makes money out of the
information they pick up in some way or another.



Pete