Re: [seam-dev] qualified bean names
On 14 Apr 2010, at 19:14, Dan Allen wrote:
On Fri, Apr 9, 2010 at 10:53 AM, Pete Muir <pmuir(a)redhat.com>
wrote:
* Changed the requirement to be to use org.jboss.seam.* as the prefix for the bean name.
We will add an extension for CDI that allows aliasing namespaces such as org.jboss.seam to
a short prefix (such as seam.). Anyone fancy coding this up quickly for Weld Extensions?
I missed this one. We had a long chat about this in #seam-dev a few weeks ago and drew
these conclusions.
Using long qualified bean names (i.e.,
@Named("com.acme.framework.module.beanName")) immediately introduces the need to
shorten (or import) them in someway. The approach that was taken in Seam 2 was to qualify
every name with the prefix "org.jboss.seam." and then add all of these
namespaces to a list of auto-imports in jboss-seam.jar. But that defeated the whole
purpose of having a qualified name since now each component had two names, the short one
(e.g., "statusMessages" and the long one
"org.jboss.seam.international.statusMessages"). So global imports provided by
the library are meaningless.
Not 100% meaningless, it makes it somewhat easier if an end-user wants to remove the short
names.
That brings us to local imports. Since bean names are only meant to be used in the EL
(which in most cases is the view), we ask, how to we import the names in the view? I posed
this very question to Lincoln. I suggested:
<s:importNames namespace="org.jboss.seam.faces"/>
Understandably, he challenged me by saying (paraphrase) "you must be doing something
wrong if you need that".
I disagree. Does this mean that Java is doing something wrong by requiring
import org.jboss.seam.blah.Foo;
I'm pretty sure that people thought this was a major pain and that the Java language
designers had made a mistake requiring qualified imports until modern IDEs generally
supported automatic importing. In fact, you can see the leftover of this in a few places
(people using the .* import for example).
If we had tooling for this, would this change your opinion?
We came to the understanding that having a protected namespace is
good, but having a namespace that you can't easily type is bad. We concluded that
since we "own" the Seam name, people should be willing to accept that we can
prefix our names with "seam" and that should be enough to ensure that they
don't conflict with application names. In the example above, I can avoid the import by
using the name:
seam.statusMessages
I think bean names should be unique across all our modules so we can avoid having to put
the module name in the bean name "seam.international.statusMessages". You can
always tweak the name to make it unique.
The question we need to ask, is, why not?
Because it doesn't follow conventions.