As you might think this is not a good way to go. You should organize your business logic into services that are separate from user flow. That means you first you have to ask for user confirmation, then go with the changes. Even if your service fails to update the database you still can report the error to the user and send him back to editing to correct the errors:Hey All,
New user to cocoon here, and I've got a question about the use of continuations in flow scripts.
I'll explain my question with the following block of code:
1: function myFunc()
2: {
3: var myDB = Database.getConnection("myPool");
4: myDB.setAutoCommit(false);
5:
6: .. do some work on the connection, don't commit
7:
8: cocoon.sendPageAndWait("confirm_changes.html");
9: 10: if (cocoon.request.getParameter("confirm_changes") == "true")
11: myDB.commit();
12: else
13: myDB.rollback();
14:
15: cocoon.sendPage("change_made.html");
14: }
In this example I get a connection to a database, make some changes and then allow the user to confirm they are happy with the changes and then depending upon their response, either commit them or roll them back.
Now this is all fine assuming the user follows the confirmation or cancellation links on the page - however, assuming there is a menu system on the confirmation page it is possible for the user to break out of the continuation without completing it, hence leaving uncommitted changes in the database.
Is there anyway I can trap the user activating links on the site (assuming they activate another resource in the current site-map)? I have a feeling I may be thinking about this in too much of a Java-ish way and there should be another way I should be doing this :)
I'm expecting somebody to say "Why not let the user confirm any changes before applying them to the database", well the reason for doing this is it allows me to trap any errors (ie. things like duplicate keys, or invalid foreign keys) that show up when you apply the changes to the db and then show these to the user before I ask them if they are happy with the changes.
var error = null;
while( true ) {
form.showForm( "edit-data", bizData );
form.save( bean );
try {
someService.performAction( bean );
cocoon.redirectTo( "mainpage" );
} catch( e ) {
error = e;
}
if ( error != null ) {
cocoon.sendPageAndWait( "errorHasOccured",
{ exception: error} );
}
}This code loops until the service gets properly executed. Still the user can follow other link and leave the continuation which in turn will expire after some time.
No problem witch resource management. No problem with scalability (holding open connections while user drinks coffee is a BadThing (tm)). Also you can make your service testable which could be PITA in your approach.
-- Leszek Gawron [EMAIL PROTECTED] Project Manager MobileBox sp. z o.o. +48 (61) 855 06 67 http://www.mobilebox.pl mobile: +48 (501) 720 812 fax: +48 (61) 853 29 65
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