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I'm making a Servlet application using the a MVC-like implementation, however I'm slightly confused on how I should delegate concurrent modification of the state of the Model object?

I intend to use a database to hold information from a given session for a particular individual (the data will be retrieved based on a username and password).

It doesn't seem possible or practical to store a Thread in the Model object, so that's really not an option.

I do want to respect the MVC implementation such that the View is dependent on the Model object and the Controller changes the state of the Model.

The question is, how do I make the View update when the Model changes state? The View is going to be a JSP that has action-value attributes. Since the View is really just a page (and not an object), how do I tell the page to refresh based on the new information? Must I rely on the Controller to do so?

I understand that Servlets run in a multi-threaded server environment, though I'm not sure how this is exercised upon the model. It seems like a waste to force the page to be refreshed every millisecond (and potentially costly to the client), though I don't understand any other way for the type of program I wish to write.

To be slightly more specific, I'm planning on remaking Snake-it in a Servlet environment as a practice program for JSP and Servlet programming. The information will be stored in a database for a given session.

Any feedback would be appreciated. Thank you.

-Alex

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Last Post by Alex Edwards
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Though this doesn't quite answer my question, a good amount of information provided by peter_budo was found here.

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I need to point out, that the post is not finished yet. I will get rid of snippets (need to gather some more info), improve DB, implement PreparedStatements and provide some additional info on some points. I hope to finalize it in next two weeks and get it approved

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Most of the information is pretty straightforward in terms of Model 2.

However, I'm still struggling to understand how to implement my design for this project...

I don't know if what I need is an Active Server Page, or a Page that, somehow, listens for changes in the database and refreshes accordingly... or simply (if possible) have a thread active that will (somehow) refresh the page whenever a state change in the Model is visible.

I'm completely at the mercy of learning Servlets more thoroughly, which I don't have a problem with. I'd just like to know if what I'm attempting to do is easy, or hard, from an experienced Servlet/JSP-user's perspective.

-Alex

Edit: Will I need to implement Java-code in the View instead (for example, a Panel or some kind of Swing component)? I don't know of what's allowed in a HTML, but I'd assume that Swing components are ok.

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I hope these questions don't seem stupid!

If an elaboration is needed, the intent is to make the Snaker animated in the View for the Model 2 scenario. Unfortunately this means that the Model must be updated constantly along with the View.

I want to hold true to the MVC pattern, though I'm not sure if I can do it in this way. The only other option is to allow the Controller to have a thread to constantly change the state of the model so the view can reflect the changes.

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