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Doing this well depends on some form of centralized data retrieve dispatch/caching.  You make calls to this centralized service to get the objects by id that you are interested in.   It either finds them in cache and can return them immediately, or adds them to a queue of objects to retrieve.  After all requests have been made (ie on DeferredCommand), a single request is sent to retrieve all objects of all types needed.

You could use an event bus to indicate all the objects where data is now available. This could even be a single event instead of one for each object, and the event handlers can ask if their objects of interest are now available, avoiding multiple updates.

there is a clear distinction between *what the browser needs* (DTO) and *what the business needs* (domain objects). When you send JDO objects across the wire, you are sending your domain model. Its not what the browser wants, and that is a problem. Soon, you will have a presentational information in your domain model, and you will have restricted information being sent to the browser, and it will be a big mess. So, take a step back, and separate Domain objects from Presentation objects (or DTOs). Make your RPCs revolve around a particular view, and send all necessary information for that view in one RPC call. Note that now your Person would include company name and company id, but not the entire company object. Now, when the user clicks the company in the view, you make a RPC call to get company information (because you have company id). That's it. Works nicely, without having to make multiple calls.

the data presentation widgets use a 'flyweight' design. Rather than being a container of other widgets, which can tend to be heavy, they build up chunks of HTML that is injected into the DOM. This not only speeds up initialization, but also reduces the event handling overhead that can slow down user experience when there are hundreds of widgets within a view.

The MVP Framework is an app framework that makes it easy for you to connect Data Presentation Widgets with backend data. Using this framework you create views that are focused on displaying data, Activities and an AcivityManager which are the "presenters", responsible for handling self-contained actions, and RequestFactories that fetch and propagate model changes throughout your app.

To make developing apps of this style easier, the 1.1 M1 release of Spring Roo, can generate and maintain the boilerplate code associated with connecting your app's components with GWT's MVP Framework.

MVP Framework The MVP Framework is an app framework that makes it easy for you to connect Data Presentation Widgets with backend data. Using this framework you create views that are focused on displaying data, Activities and an AcivityManager which are the "presenters", responsible for handling self-contained actions, and RequestFactories that fetch and propagate model changes throughout your app. To make developing apps of this style easier, the 1.1 M1 release of Spring Roo, can generate and maintain the boilerplate code associated with connecting your app's components with GWT's MVP Framework.

the data presentation widgets use a 'flyweight' design. Rather than being a container of other widgets, which can tend to be heavy, they build up chunks of HTML that is injected into the DOM. This not only speeds up initialization, but also reduces the event handling overhead that can slow down user experience when there are hundreds of widgets within a view.

To upgrade to 2.1 M1, simply do the following Download GWT 2.1 M1 from the download page and unpack it to the directory of your choice. If you use Eclipse to develop, you should also download the Google Plugin for Eclipse from the same download page. Update your GWT project build path to use the latest gwt-user.jar and gwt-dev.jar (and any other GWT jars that you included on your classpath). Replace references to gwt-dev-<platform>.jar with the location of the new gwt-dev.jar (there is no longer a platform specific suffix). Update any run configurations or application compile and shell scripts to include the latest JARs in the classpath (same JARs as mentioned in step 2). Run a GWT compilation over your project to generate the latest GWT application files for your project. Deploy the latest GWT application files to your web server.

the MVP pattern has nothing in common with GWT's Place/History management framework (often referred to as GWT MVP). If you use GWT places/activities your app will gain bookmarkable urls that represent a place/application state and whenever such a url is visited a corresponding activity will be started. This activity is then responsible for attaching some UI/widgets to an area of your webpage. If this UI is complex and has user interaction elements then you could implement this UI with the MVP pattern to separate the UI from the logic that will be performed when the user interacts with this UI. And once you decide to use the MVP pattern then its in most cases easier to let the activity be the presenter. But its also possible to implement a separate presenter and let the activity hold a reference to it.