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"department is navigable through college"?

Sybyll Jones
Greenhorn

Joined: Dec 20, 2007
Posts: 14
Hello, i am a little confused about this:
In one test if found the assertion, that:
"departments are navigable through college".
But in another example they say:
student[] is navigable through the School class is WRONG??

I'd thought, that this navigable thing has only a meaning in combination with this UML-Arrow (can be traversed in one direction: example: Book ---> pages):
A book knows about its pages, but a page doesn't know what book it's in...).
So Book is navigable though pages??
Has the composition-relation an effect on the navigation?

Thanks
Syb.

[ June 25, 2008: Message edited by: Sybyll Jones ]
[ June 28, 2008: Message edited by: Sybyll Jones ]
Amey Rane
Greenhorn

Joined: Mar 21, 2007
Posts: 15
I could not understand what your question is;

I would however like to explain whatever I know about navigation. In UML you are right when A---->---B U can say that B is navigable through A. In Java Code Navigability usually means that set or get methods for the instance variable of class B are defined in A. If there are no methods accesing or mutating an object of class B in A you will see this in UML A-----B

The line shown here is a solid line...(Dont mistake with interfaces)
Stephen Davies
Ranch Hand

Joined: Jul 23, 2008
Posts: 352
Yes, don't forget that navigability manifests through setters and getters (accessors and mutators) simply "has a" eg A book has pages[] merley denotes an association (UML: Solid line with/without multiplicity indicators). If the Book class then has methods akin to getPage, setPage etc then one may say pages are navigable through book. (Although a page and books represents a composition association as if one were to destroy the book class, all the pages would also be destroyed)

Hope this helps


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