About the adaptor design pattern

[Tony Johansson]

Hello!

I'm reading about design pattern adaptor in the GOF book and
there is something that sounds strange.

When you use the adaptor design pattern you have these participants.
*Target
- defines the domain-specific interface that Client uses.

* Client
- collaborates with objects conforming to the Target interface.

*Adaptee
- defines an existing interface that needs adapting.???

*Adaptor
- adapts the interface of Adaptee to the Target interface???

Now to my first question. I can't understand the text row for Adaptee saying
"defines an existing interface that needs adapting."
What does they mean when the existing class needs adapting?
No class need any kind of adapting as I understant it.
The adaptor design pattern say that you just use the implementation from the
existing class.

Here the second question. I can't understand the text row for Adaptor saying
"adapts the interface of Adaptee to the Target interface"
The same here this must be wrong saying adapts the interface of Adaptee to
the Target interface.

Many thanks

//Tony

[Oliver Wong]

"Tony Johansson" <jo*****************@telia.com> wrote in message
news:F3*********************@newsc.telia.net...

Now to my first question. I can't understand the text row for Adaptee
saying
"defines an existing interface that needs adapting."
What does they mean when the existing class needs adapting?
No class need any kind of adapting as I understant it.
The adaptor design pattern say that you just use the implementation from
the existing class.
Did you see my responce regarding DirectX versus OpenGL? Sometimes you
have two classes, and you want them to communicate, but their interfaces are
not compatible. Thus it needs adapting.

Here the second question. I can't understand the text row for Adaptor
saying
"adapts the interface of Adaptee to the Target interface"
The same here this must be wrong saying adapts the interface of Adaptee to
the Target interface.

This isn't a question, but I'll try to guess what the question it is
that you are asking. Here's the answer to what I assume your question is:
"No, it's correct."

- Oliver