Dynamic fields in JSF beans

I want to let my client c开发者_StackOverflow中文版reate his own fields and bean in the CMS dynamically.

As well, once he creates a form, I need to create an Hibernate Entity that could be saved to the database.

Is there a way to do it?

I am using JSF2 and Hibernate 3

With recompiling and without?

Creating tables and entities dynamically is IMO not a good idea. Hibernate is not really made for that and generating entities is only a small part of the problem. You would have to add them to the configuration, rebuild a session factory, update the model. And what about subsequent restarts of the application? Not recommended, just forget this approach...

Another option would be to use an Entity-Attribute-Value (EAV) model. This is something many CMS are doing. I've never implemented this with Hibernate but it's doable (and has already been done). Here are some resources:

• Adding new persistable classes at runtime
• [hibernate-dev] dynamic entities (has some sources attached)

But to be honest, I wouldn't implement my own CMS but rather reuse an existing one. One Hippo seems to be a candidate.

See also

• The CCK buzz (Content Creation Kit) and the EAV problem

Related questions

• Entity Attribute Value Database vs. strict Relational Model Ecommerce question
• Approach to generic database design
• How do you build extensible data model
• I am looking for something similar to the drupal CCK, but in Java (in a Java CMS)?
• Java Frameworks that support Entity-Attribute-Value Models
• Implementing EAV pattern with Hibernate for User -> Settings relationship

Easiest way would be using a List<String> for the field names and a Map<String, Object> for the field values. Maps can be accessed in EL using dynamic keys like so:

<ui:repeat value="#{bean.fieldnames}" var="fieldname">
    <h:inputText value="#{bean.fieldvalues[fieldname]}" /><br />
</ui:repeat>

A completely different alternative is to autogenerate classes using tools like ASM/Javassist and creating database tables on the fly. But that's a lot more work.