Another Example: Streamers

• But why go through so much effort?  Why don't I just tell the view exactly what I want?
• Well, with model-view-controller (MVC), the look of the interface is separated from the data.  So, that means you can plug in a new view very easily, without chaning the representation of the data.  You can even have two simultaneous views.
• Another example... Many on-line brokerages offer a streamer., which constantly sends live stock quotes to the brokerage's customers.  Let's say we have three customers with different interfaces-Macintosh, Windows, and Unix.  Each user has an interface that matches his or her desktop.  This is fine, the views can be different, because the view is separated from the data.
• When a stock quote changes, the brokerage passes this information to its customers.  Perhaps it sends a Java object, via Remote Method Invocation, that has the stock ticker symbol and its price.  This is the model.
• The controller has a method for accepting that object, and can update the view.
• Again, the view is what the user sees.  When the controller updates that view with the new data, the user sees the new data.  Since the data and view are separate, each user sees the data in the preferred format.
• What if the brokerage even offers different ways to see the data?
• In the above example, we assume that the users are using a 'fat client', or an application with an icon that starts it up, and a Swing-based interface.
• Say the brokerage wants to have streaming information on its website as well.  It can do this either with HTML or a Java Applet.  The HTML and the Applet are the view in this case.  Theoretically, the brokerage can re-use the same model, and perhaps even the same controller, with only having a different view!  Imagine the savings in writing and maintaining only one small set of objects for each of these presentations!
Layout Management

Created by:  Brandan Jones January 4, 2002