I have built a few Web apps using Cayenne quite successfully but now I
am building my first standalone app and have a few questions.
In a Web app, I have typically just setup my Tomcat configuration and in
my code I execute something like ObjectContext context =
BaseContext.getThreadObjectContext() and let the "magic" happen.
In my standalone application I don't think it will be quite that easy.
I will have multiple short lived threads requesting database information
simultaneously so I'm not quite sure how to manage the Cayenne
components. At first I thought I could simple do a
DataContext.createDataContext() and I'd be fine but "Creating a new
DataContext for each request is not a recommended practice." So I
understand the need for a single DataContext and so I think I found the
answer in createChildContext() but,
1) Do I need to manually create a child context in each thread? But
what should I do when the thread has completed its transactions and is
ready to terminate? I don't see a corresponding "destroyChildContext"
ObjectContext oc = getDataContext().createChildContext();
2) Or is it better to create a pool of ObjectContexts that I have to
manually manage access to within the threads - or does Cayenne have
something like this already built-in?
3) Is the maximum simultaneous createChildContext calls tied to the
ConnectionPool limits in the Modeler? To me the "createChildContext"
implies creation without limit so if they are somehow linked how will I
know that the underlying ConnectionPool has run out of resources?
4) Or am I way off base and making things more complicated than they
should be? ;-)
Sorry if I've missed the answers somewhere in the documentation but I
haven't been able to Google successfully for something I've fully
understood.
Thanks,
Andrew
