Re: Defining Source Interfaces

[Sylvain Wallez]

Carsten Ziegeler wrote:

Sylvain Wallez wrote:

<snip/>

And as far as code cleanliness is concerned, an "instanceof" test seems
more OOP to me than a isTraversable() method that tells us if is we have
the right to use getParent() and getChildren(). With a separate
interface, these methods do not exist if they do not make sense.

This is a point were a not really agree with. If I always have to do instanceof tests and class casts, something is wrong with OOP then in my eyes.

Following Stephen's example, I grep'ed instanceof on the whole 2.1 source base and found... 388 of them !

Anyway, I think your arguments are better than mine (sniff).

So, we have a TraversableSource or HierarchicalSource or ...?

I'm not a native speaker, but the definition of traversable given by dictionary.com makes me prefer hierarchical...

Ah, and what about adding an "exists()" method on Source (it's currently on WriteableSource) ? That one makes sense and is really useful, as the current way to know if an URI exists is to try to getInputStream(), which can be heavy.

What do you think about the ModifiableSource in Excalibur? (That should be
the replacement for WriteableSource - please let *me* win this time ;) )

Hey, you won on the SourceFactory.release() !

But I don't want to count points or judge anyone/anything. I just want things to be nice, and, well, we sometimes have different feelings about what is nice ;-)

I'm not sure about the "Modifiable" name. Maybe I'm biased because it was formerly (in 2.0) used to name something else ? Don't you like "WriteableSource", or "OutputSource" ? Don't know...

Whatever its name, it would be good for this interface to have the canCancel() and cancel() that are on WriteableSource. These allow data that has been written to a source to be discarded if something goes wrong. This is especially usefull in pipelines using the SWT for example.

About the move() and copy() methods, I don't know if they should be kept in the new incarnation of this interface.

Sylvain

--
Sylvain Wallez Anyware Technologies
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