Java Reference
In-Depth Information
Consequences
Benefits
•
Improved flexibility
: The application now consists of smaller view components
such as controls and containers embedded in layouts. This makes the view easily
configurable, and changes to the application look and feel, as well as component
positioning, can be rolled out quickly and efficiently.
•
Improved reuse
: With this pattern, the same subview can be used to compose mul-
tiple composite views.
Concerns
•
Performance
: When composing a view, using multiple subviews can impact per-
formance. Hence, you should be judicious in keeping the subviews to an
acceptable number.
Dispatcher View
Problem
eInsure had a sign-in page that presented a simple UI to accept a username and pass-
word. This screen also had a button control that, on being clicked, triggered the
authentication action. Hence, the presentation of this sign-in page did not require any
business logic invocation. There were many other pages similar to this. There were sev-
eral pages to display the input criteria that can be supplied before triggering a search for
the policy, claim, and so on. Then we had lookup pages for various codes used in the sys-
tem. All the values used for lookup were loaded from the database at startup and cached
on the server. This was possible because the static data never changed when the applica-
tion was up and running. Also, the action to load the UI pages to create a policy or claim
required only user information that was cached in the session. Last but not least, almost
each page had a link to open a help page. The static HTML-based help pages provided
context-sensitive help to guide the users on how to use the different features (buttons,
menus, text boxes, and so on) in that particular page.
