Can you clarify for me this...
I have Jetty...and I want to add a connector. I want my application to
listen on port 9000 too. I need a GBean. Do I need the source?
I have Tomcat, and I want to add a logging Valve or Single Signon Valve.
I need a Gbean. Do I need the source?
I need to be able to configure these things and have the ability to add
a GBean w/o the source. Will we have this capability for M5 or 1.0?
Jeff
Aaron Mulder wrote:
On Fri, 12 Aug 2005, David Jencks wrote:
What I'd like to see is:
--gbeans have regular persistent attributes and manageable attributes
--the configuration expose the manageable attributes of the gbeans
inside
--you can only change the manageable attributes of a compiled
configuration: to change anything else you have to rebuild the config
Just as a reminder, we already agreed on a strategy for
configurations where they will be able to be flagged as "immutable", at
which time you could only change what we're now calling manageable
attributes. For a "mutable" configuration you could change anything.
Jeremy was going to think about what it would take to implement the
"mutable" flag on configurations, as well as adding version numbers and so
on.
--a database abstraction/interface for the manageable attribute values
so we can save just these values: everything else is read from the
config
--a properties file or xml implementation of the db interface so people
can edit stuff.
I'm fine with this -- I don't think it would be very hard to
implement. I expect a GBeanInfo would have a separate Set of manageable
properties, and the "manageable property database" would be part of the
kernel, so when a Configuration starts a GBean it could look up any
manageable properties for the GBean and override them when loading the
GBean. The only problem is that I'm not sure how we'd work around
properties that the GBean expects to be set in the constructor -- since
the GBean is deserialized the Configuration doesn't have the opportunity
to call the constructor, so (for the short term) we'd probably need to
require that manageable properties can be set via a setter before the
GBean is started (and then the Configuration could do it after the GBean
is deserialized).
I do prefer XML over properties, and since we don't (AFAIK) want
the kernel to depend on XMLBeans, I think we could use SAX or DOM to read
the database config. I'm OK with that since I think it would be quite
simple -- something like:
<config>
<gbean name="...">
<property name="port" type="java.lang.Integer">8080</property>
<property name="host" type="java.lang.String">0.0.0.0</property>
</gbean>
...
</config>
Oh, and since I know David J hates maintaining XML parsing code, I
volunteer. :)
With this, you really would have to be able to start a configuration
before you could edit values, and there are still serious problems if
someone edits the db while the server is running, or if someone changes
a configuration but not its version.
Well, configurations don't have versions yet, and I think that may
itself be a big change, so I think we could go ahead with the manageable
properties but not the configuraiton versions for now.
As far as changing the DB while the server is running, we can
either say that it only takes effect on restart or we can arrange for the
appropriate setter to be called at runtime. We can also probably arrange
for calls to the setter at runtime to update the database.
Any other ideas on how to do this? Any ideas on how long it would take
to implement some or all of this?
I suspect it will take longer to agree on what we want than to
implement it. :)
Aaron
