Adding custom exporter by extending toolset vs. modifying?

plutonianelephant · **Joined:** Tue Nov 15, 2005 6:56 pm **Posts:** 39

Using HibernateTools3.1.0Beta1.

Trying to figure out best way to add an exporter without modifying code but rather extending the toolset. Is there a way?

My particular need for the custom exporter is explained below.

I'm trying to figure out which is the best way to programmatically set the meta attribute "use-in-equals" on properties. Basically, I know I want to do some code like this:

Code:

property.getMetaAttributes().put("use-in-equals", meta);

1) Is the above code the best way to do this?
2) Which is the best place to put the code? Preferably extending the classes rather than rewriting them would be better.

I originally thought of creating my own MyHbm2JavaGeneratorTask class and MyHibernateToolTask classes. The plan was to have MyHbernateToolTask derive from HibernateToolTask and just add this method:

Code:

    
public ExporterTask createMyHbm2Java() {
   ExporterTask generator = new MyHbm2JavaGeneratorTask(this);
      generators.add(generator);
      return generator;
   }

MyHbm2JavaGeneratorTask.confiureExporter would programmatically add the "use-in-equals" meta attribute.

Unfortunately, the generators member field is private in the super class HibernateToolTask, so I couldn't do it this way. The other solution that does work is to just create a new class parallel, instead of derived, to the HibernateToolTask and duplicate all the code and add my extra method. This, however, was what I didn't want to do since it involved changing the existing code.

So, essentially, I think my problem can be more generally stated as how does one add a custom exporter task by extending the toolset rather than modifying it? Is there a way?

Any help is appreciated.

Thank You.

max · **Posted:** Wed Nov 16, 2005 5:09 am

hmm - so you want to alter the hibernate meta model *before* it is handed to the exporters.

That is doable if you simply just add a <hbmtemplate class="your.mutator.ClassName"/> which will be handed a Configuration which you can actually modify (be carefull and remeber to call cfg.buildMappings() ;)

plutonianelephant · **Joined:** Tue Nov 15, 2005 6:56 pm **Posts:** 39

Thank you for the suggestion. I'm a newbie to Hibernate, so I hope I understood you correctly.

I ended up deriving a class from GenericExporter and overriding the setConfiguration(...) method. I called the super classes setConfiguration method first and then did my code to add meta attributes to the configuration. Something like this in MyPOJOExporter.java:

Code:

public void setConfiguration(Configuration cfg) {
         super.setConfiguration(cfg);
         // my code here
}

I then called it in my ant file like this:

Code:

<hbmtemplate template="pojo.vm" exporterclass="com.mycompany.MyPOJOExporter" filepattern="{package-name}/{class-name}"/>

It seems to work. However, I did not end up calling cfg.buildMappings() like you warned about. Is that necessary and where do I call it?

Thanks for all your help.