Calling another application using object carousel

Question

hi, i'm currently developing several applications in mhp, i have 5 mhp applications, i wrote them each with individual xlets, now, one of its application serves as a main menu for other applications, the main menu should call or run another application in another carousel. so i studied how to use carousels. and here's my code below. the locator and the carousel ID is just an example. pls. help me check if this codes are correct or if there something i need to modify
Locator locator;
int carouselID;
String locStr = "dvb://123.456.789";
ServiceDomain carousel = new ServiceDomain();
try {
locator = new DvbLocator(locStr);
carouselID = 5;
carousel.attach(locator, carouselID);
carousel.getMountPoint().synchronousLoad();
} catch (ServiceXFRException e) {
e.printStackTrace();
} catch (InterruptedIOException e) {
e.printStackTrace();
} catch (MPEGDeliveryException e) {
e.printStackTrace();
} catch (InvalidLocatorException e) {
e.printStackTrace();
} catch (InvalidFormatException e) {
e.printStackTrace();
} catch (ServerDeliveryException e) {
e.printStackTrace();
} catch (InvalidPathNameException e) {
e.printStackTrace();
} catch (NotEntitledException e) {
e.printStackTrace();
}

Answer 1

The code you have will work, but will almost certainly not do what you want. It will load the directory entry for the root directory of the carousel and nothing more - using this approach to load multiple applications from another carousel is hard work and fairly error-prone.
An easier solution is this:
1) Broadcast all your applications as separate apps. They can be in the same carousel or different carousels.
2) If you only want the launcher application to be visible in the application list, set the visibility of the other applications in the AIT to be invisible to users but visible to the application listing and launching API.
3) Use the application listing and launching API (org.dvb.application.*) to launch the sub-applications when you want to. This works via the normal application manager, so it will take care of making sure the carousels are mounted correctly.
The disadvantage of this approach is that sharing information between the launcher app and other apps gets harder, and you will need to use the inter-Xlet communication API to get round this. It will save a lot of trouble with carousel management, however.
There are other approaches (e.g. using DVBClassLoaders), but using separate carousels tends to complicate things. Is there a good reason for doing this, or can you store all of the applications in a single carousel?
Steve.