[Zope3-Users] third try: containment

[catonano]

Hello zopers,

well this is my third try to ask a question, after the first two ones 
went totally ignored, in the last few days. The second one was quite 
simple: how do I instruct the ftp server to write some lines in the 
access log ?

Silence. How comes ? Did I hurt or piss off anyone ? If so, I'm 
sorry; I'm ready to apologize as soon as someone explains me what I got wrong.

Anyhow, here's my third try: I'm trying to learn the Zope 3 
architecture and costumes starting from the book example (the 
messageboard and the messages).

I created two example components: shelf and book. Of course, a shelf 
can contain books.

So far my components are NOT persistent. The do NOT inherit from 
Persistent nor they do implement some sort of persistence themselves. 
This is because I'm just trying to explore the containment stuff and 
I don't want to put in too many layers too early.

My shelf has no attribute, the only difference between it and the 
common folders (containers) is that shelf can contain books ONLY.

A book has 3 attributes: title, author, editor; it can be contained 
in a shelf only and it is NOT a container; it can't contain anything.

In the ZMI I see my components, I added a shelf and inside the shelf 
a book. So far, so good !

BUT, when in the book component, one of the views the ZMI offers is 
"content", which, as far as I know, is referred to the containers 
contents and my book is NOT a container ! I swear ! It does NOT 
implement the IContainer interface or any descendant interface !

Still the ZMI offers to see the contents of it. If I click on the 
contents tab a white screen pops up telling my a system error 
occurred, and the output in the terminal shows a message about a 
forbidden attribute "items" called.

How is that ? The ZMI takes it correctly when it's about to add 
content to the shelf, proposing to add a book only, in the left bar, 
and also, inside the book component, there's no action "add" in the 
actions stripe. Still, there's the content tab in the views tabs !!

How is that ?

I'm on win XP and Zope 3.3.1

Thanks so much anyone for any hint !

Bye
Catonano