GeneratedPropertyContainer and CommitHandler, getting the Bean data?

I previously had a BeanItemContainer for my Grid, but I needed to add a column in my grid for a button, so I used a GeneratedPropertyContainer.

But I'm getting the error:

Caused by: java.lang.ClassCastException: com.vaadin.data.util.GeneratedPropertyContainer$GeneratedPropertyItem cannot be cast to project.test.Bean

how do I get the Bean from GeneratedPropertyContainer?

For BeanItem Container, I could do this:

public class CustomCommit implements CommitHandler {
    public CustomCommit() {
    }

    @Override
    public void preCommit(CommitEvent commitEvent) throws CommitException {
        BeanItem item = (BeanItem) commitEvent.getFieldBinder().getItemDataSource();
        Bean bean = (Bean) item.getBean();
    }

But for GPC I can't figure out how to get the bean?

Thank you, that worked!

public class CustomCommit implements CommitHandler {
    Bean beanPrevious = null;

    @Override
    public void preCommit(CommitEvent commitEvent) throws CommitException {
        GeneratedPropertyItem gpItem = (GeneratedPropertyItem) commitEvent.getFieldBinder().getItemDataSource();
        BeanItem item = (BeanItem) gpItem.getWrappedItem();
        Bean bean = (Bean) item.getBean();
...
}