[jdom-interest] Factories

[Chris B.]

Alex Rosen wrote:

>I vote for class or abstract class. Here's part of my notes from one of
>the presentations at EclipseCon a few weeks ago.
>
>"He advised that you shouldn't create interfaces that you expect users
>to implement - use abstract classes instead, for forward compatibility.
>  
>

True, but you lose all the good things about interfaces - the ability to 
have multiple "inheritance". Why not have both? With suitable warnings 
about the dangers of using the interface instead of the abstract class?

>You can't add new methods to an interface that a user is implementing -
>you have to use the hacky "MyInterface2 extends MyInterface" workaround.
>He said that wherever they've had interfaces that users are expected to
>implement, they've regretted it. (Having interfaces that the user is not
>expected to implement, to hide your implementation classes, is fine.) He
>had a big bushy programmer's beard, so he must know what he's talking
>about."
>
>Alex
>
>  
>
>>>>Jason Hunter <jhunter at xquery.com> 2/27/2004 9:30:50 PM >>>
>>>>        
>>>>
>FYI, I just made an interesting commit.  People not on the commits list
>
>might want to take a look:
>
>http://lists.denveronline.net/lists/jdom-commits/2004-February/001745.html
>
>
>This change also made me think, should JDOMFactory really be an 
>interface, a class, or an abstract class?  The problem with an
>interface 
>is that if we add methods after 1.0 it breaks everyone implementing the
>
>interface.  With a class or abstract class, we can add w/o breakage so
>
>long as the new methods can have a standard implementation.
>
>-jh-
>
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