Head First OO Book- Class Diagram Question

[James Chegwidden]

Got a copy of the new head first OO book...

Question on Class Diagram in particular Interfaces and representation.

In UML 2.0 reference books Interface methods/attributes are not italics

in particular in Learning 2.0 and other UML references in basically says.."..unlike abstract classes, an interface does not have to show that its operations are not implemented, so it does not have to use italics."...

But in Head First OO (p. 224 and others) and in other Java programming books...Interfaces are italicized in UML..

Questions.

1. Why the incosistencies?
2. Which is correct- italic or non italics...or is it optional and if so why not say so- instead say one way or other...


I thought this question was answersd a while back but there seems to be inconsistent in notation..jc

[Ilja Preuss]

To me, "does not have to" means exactly that it's optional. It implies "but it may".

[Peer Reynders]

The The Unified Modeling Language Reference Manual 2e (2004) states under "font usage": "Italics are used to indicate an abstract class, attribute, or operation". It then proceeds to use the �interface� stereotype for interfaces and only use a normal font.

This is kind of a contradiction because interface operations are abstract.

In the absense of font styles you can use property lists i.e.:
abstractOperation {abstract}
instead of
abstractOperation
[ December 14, 2006: Message edited by: Peer Reynders ]