Re: [JBoss-user] What's the best java.util.Collection to return?

[Brandon K. <kni...@bl...>]

Excellent, thanks a ton!  I missed the unmodifiable method! :)

As for DTO's, yeah I keep hearing that from ppl.  Since I'm just following the
book along I'm reading, I'm learning what can and can't be done.  After that,
from doing server-side programming for a few years, then I will pick the best
method that reaps performance and ease of use/extensibility.  

With that said, I'm getting a little help from my friends at Wiley, I picked up
the EJB Patterns book.  Good reading, I think I'm just a little too junior on
the EJB side yet.  Thank god for home projects where you can cut your teeth on
something not job critical! :)

Thanks again!

-- 
-bk


Quoting David Ward <dav...@do...>:

> If you really want to return an unmodifiable Collection structure, you 
> can use one of these helper methods in the java.util.Collections class:
> 
> static Collection unmodifiableCollection(Collection c)
> static List unmodifiableList(List list)
> static Map unmodifiableMap(Map m)
> static Set unmodifiableSet(Set s)
> static SortedMap unmodifiableSortedMap(SortedMap m)
> static SortedSet unmodifiableSortedSet(SortedSet s)
> 
> So you could do:
> {
>      ...
>      origList = new ArrayList();
>      origList.add(x);
>      ...
>      return Collections.unmodifiableList( origList );
> }
> 
> Just make sure the contents of the Collection are Serializable or Remote.
> 
> Now, that being said, if this EJB you're talking about is a stateless 
> session bean (slsb) accessing entities, it would be ***BAD*** to return 
> remote interfaces of those entities.  Much network calls and separate 
> transactions = bad performance and more.
> 
> Instead, use local interfaces to your entites from your slsb, put the 
> data into Serializable data transfer objects (reg. javabeans, or 
> "dto's"), shove them into an ArrayList, and return that.  Of course, 
> that's just one (common) design pattern among other viable options.
> 
> Hope this helps,
> David
> 
> --
> 
> Brandon Knitter wrote:
> > Okay, I know this is not JBoss specific, but I got a good response from my
> last
> > question, and this is a question in the context of EJB.
> > 
> > When returning a java.util.Collection, what object is the best to return? 
> I'm
> > assuming that returning a Vector is not really a good idea as it is able to
> be
> > modified.  What options for immutable Collection implementations are
> there?
> > 
> > 
> 
> 
> 
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