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Rishi (1) [Avatar] Offline
I am using the exposed domain model pattern. In order to prevent the presentation tier to perform updates without going via a domain service I am writing the presentation tier using read only interfaces of the domain objects. This strategy is suggested in your book on page 293 while using the domain model pattern.

I am using Hibernate for the persistence tier along with Spring in the business tier. I am using Springs OpenSessionInViewFilter to keep hibernate sessions open until rendering of the page is complete.

But I am confused as to how an update would be performed if only a read only interface is returned to the presentation tier.


Suppose I have the Domain object interface Person and its concrete implemetation PersonImpl, and a Service class as follows:

interface Person {



class PersonImpl implements Person {

private String name;

public getName() {

public setName(String person) {
this.person = person;


class PersonService {

Person readPerson (String name) {

void updatePerson(PersonImpl person) {

My question is this - When the presentation tier acquires a Person Object, how will it's fields be updated, since Person does not have any mutator methods ?

Also the domain service method updatePerson expects a parameter of type PersonImpl, but all the presentation tier has is a Person.

I could not find a solution to this problem in your book or in the sample code.

Thank you in advance.

ceracm (110) [Avatar] Offline
Re: Performing Update while using Read-only views of Domain Objects

I didn't explicitly discuss the issue of the presentation tier updating the domain objects directly and so the book focusses on readonly views.

The interface should specify the methods that the presentation tier needs to call.
If it needs to update the domain object then the interface should define methods to do that.

Also, if the service expects a PersonImpl then you need to pass the PersonImpl or downcast. There is no way around that. You could change the service to take a Person and downcast internally. Alternatively, the controller part of the presentation tier to use PersonImpl but would the View part to be written in terms of Person.