On Thursday, Aug 14, 2003, at 10:10 Europe/London, Greg Wilkins wrote:
I think Jan added the array methods at my prompting.
The reason I like them is that add/remove are good for scripting & programming, but are not very good for configuration.
You just need to be able to read through the configuration using an Iterator, surely?
I've been using a system that uses MBean for persistent configuration, so it is important that everything can be set and got via getters and setters.
I don't think that it's necessarily a good thing to allow components to be built in this way. I think the container should be passed each component individually and then put in, rather than forcing an array to be put in.
At least, it doesn't have to be implemented using an array internally, even if there are requirements to get/set it as an array.
So how about the following
void addComponent(Component) void removeComponent(Component) ObjectName[] getComponents()
Even worse, IMHO. A container contains components, not JMX objects/ObjectNames. And you've still got the array, which was what I meant in my last e-mail.
But we still don't have a method to iterate over all the Components, or get them all. So either we need something like
ListIterator getComponentIterator()
Why not just Iterator? I don't see the benefit of ListIterator.
OR we just give up on typing and do:
interface Container extends Component, Collection { ObjectName[] getComponents() }
Urg. No, I don't like that at all. A Container shouldn't implement Collection -- if it does, it breaks all manner of things (not the least of which is that you have to add a whole bunch of spurious methods to a Container implementation to get it to work.
You might like to read http://nagoya.apache.org/wiki/apachewiki.cgi?IsA/HasA for more discussion on this, but a Container /is-not-a/ Collection, a Container /has-a/ Collection. You can then expose some/all of it as necessary using the Iterator, or failing that, return a read-only Collection method.
public interface Container extends Component {public Iterator getComponents(); public void addComponent(Component component); public void removeComponent(Component component);
}
Alex.
Why not just getName(), by the way?I also propose that the Component interface has one extra method:
String getObjectName();
Because it is a JMX ObjectName
I think this is one of the examples where because JMXAsKernel is being used, JMXIsEverywhere :-/
