Hi Dave,
Thanks for your reply. But the situation is quite intricate. Consider the
following action bean:
public Customer customer;
@Before(stages=LifecycleStage.BindingAndValidation)
public void preBind()
{
String id = getContext().getRequest().getParameter("customerId");
customer = customerService.findById(Long.valueOf(id));
}
@DefaultHandler
public Resolution view() {
return new ForwardResolution("/editCustomer.jsp");
}
public Resolution save() {
customerService.makePersistent(customer);
...
}
public Resolution cancel() {
return new RedirectResolution("/listCustomer.jsp");
}
The preBind() method pre-loads the customer domain object, where stripes
binding will bind direct to it. The save() method can simply persist the
domain object without having to use a data transfer object and a whole heaps
of codes to copy properties. This is the binding direct to domain object
pattern advocated in
http://www.stripesframework.org/display/stripes/Binding+Into+Domain+Models.
Now let say I want to introduce the following method:
@After(stages=LifecycleStage.BindingAndValidation)
public void afterBind() {
states = lookupService.getStateCodes(customer.getCountry());
}
The method is to load the list of states to populate a dropdown list. Fair
enough use case.
Now consider the user press the 'cancel' button.
- preBind() loads the domain object
- stripes binding binds the post back values.
- afterBind() kicks in, lookupService got invoked. Now since LookupService
is managed by the Transaction Manager, it is surrounded by open and commit
transaction. With hibernate's session per request pattern, LookupService
will also persist the customer object as well, since it is also in the
session that LookupService is using.
I know I can use @Before(stages=LifecycleStage.BindingAndValidation,
on="!cancel") to get around this problem. I can probably tweak the
Transaction Manager to always open a separate transaction. But after some
days of thinking - it seems to me that there is simply to many ways for
things to go wrong. The binding direct to domain model pattern does not
seems to be tenable.
Best regards,
Yee
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