Question about app design with JSF

Question

I'm new to JSF and have been using MyFaces in combination with Tomcat and Hibernate to write a web application for my institution. We have a fairly clean model implemented and our hibernate persistence layer is also looking good. I'm running into trouble making a clean view layer with JSF. Namely, I can't seem to avoid creating lots of classes to get a given job done.
As a for instance: I have quite a few enumerations representing various units of measure, conventions, etc. To persist them in the db with hibernate, I needed to make a converter class to convert the Enums to strings. I wrote a class using generics that could convert any enum to strings appropriately given a class object you pass into the constructor. Well, hibernate needs a no arg constructor so it can instantiate one automatically, so I had to make a subclass of this converter for each enumeration I have in my model. Couldn't see a way around it.
Now, using JSF, I'm needing to implement another converter for enumerations in order convert back and forth from strings. Same deal. I could use a single class to get the job done. The problem is, in the faces-config.xml where you define your converter classes, it doesn't look like I can have 2 converters defined with the same converter class.
i.e.:
<converter>
<converter-for-class>commons.astronomy.Epoch</converter-for-class>
<converter-class>tools.webapp.EnumConverter</converter-class>
<property>
     <property-name>enumClass</property-name>
     <property-class>java.lang.Class</property-class>
       <default-value>commons.astronomy.Epoch</default-value>
</property>
</converter>
<converter>
<converter-for-class>commons.astronomy.VelocityConvention</converter-for-class>
<converter-class>tools.webapp.EnumConverter</converter-class>
<property>
     <property-name>enumClass</property-name>
     <property-class>java.lang.Class</property-class>
        <default-value>commons.astronomy.VelocityConvention</default-value>
</property>
</converter>MyFaces seems to associate both Epoch and VelocityConvention with the second configuration of the EnumConverter class. So, the long and short of it is, here I am again having to write yet another class PER enumeration.
I could go on with another example, but this post is getting lengthy, so I'll make it short. Some of my model classes are not java beans because it would create inconsistencies to only set some of the properties one at a time. I.E. I need to call a method obj.set(a, b) not obj.setA(a); obj.setB(b). My first thought was to create a custom component for obj so that I can turn 2 (or more) input fields into 1 set call. There are other advantages in reusability, etc.
Unfortunately, I have several of those situations and am finding myself leaning toward implementing yet MORE classes to make a separate component for each such instance of a non-java bean set of properties.
What it all comes down to is I seem to be having a class explosion and I'm wondering if there's a better approach to this whole thing. How do you organize a view layer that talks to a model having enumerations and not quite javaBean pattern properties without a class explosion? That's the question I guess.
Thanks for your patience in reading all of that and any help you can provide!
brian

Answer 1

No, I don't have tables of values. I have a java 1.5 enumeration, like for instance:
public enum VelocityConvention {
   RELATIVISTIC,
   REDSHIFT;
}and a class Velocity that contains a convention and a value like so:
public class Velocity {
   public VelocityConvention getConvention() {...}
   public double getValue() {...}
   public void set(VelocityConvention conv, double value) {...}
}When I persist the Velocity class to the database, I want a field called convention that holds the appropriate value of the enumeration. That much is done how I explained before.
I want to have a selectOneMenu for setting the convention. Via trial and error, I found that MyFaces wasn't able to automatically convert from a string back to a proper VelocityConvention enum constant. It can, of course, convert from the enum to a string because it just calls toString(). But I need both directions for any UIInput element I use, be it a selectOne, or just a straight inputText.