Solutions over ADEP have introduced the concept of an application context (aka app context), which can be seen as a unique identifier, that various server side modules use to identify the execution context (from the current execution thread) and process requests in context of that solution. For instance, when persisting content/assets onto the CRX repository, the platform’s persistence module (official known as Platform Content) uses the current (invoking) app context to determine where to store the content/assets, and what configurations to use (which would typically be different for different solutions). See snapshot below, indicating the solution specific content areas.
Note that the storage location is /content/apps/cm for Correspondence Management, and /content/apps/icr for Integrated Content Review, which happen to be the app contexts for the two solutions.
Since it is essential for the server to identify the execution context, if you do not set or establish the application context before you make calls to the solution APIs, you will encounter a server error that says : “Unable to fetch application context“. To set the app context, use one of the two methods:
App context in your Flex application
If you are invoking a solution API from a flex application, ensure that you set the app context using:
var appToken:AsyncToken = com.adobe.ep.ux.content.services.search.lccontent.LCCQueryServiceFactory.getInstance().setAppContextService("/content/apps/cm"); // setting app context for the CM solution
appToken.addResponder(new mx.rpc.Responder(<your success handler>, <your fault handler>));
App context in your Java application
If you are invoking a solution API from a java based application, ensure that you set the app context using:
com.adobe.livecycle.content.appcontext.AppContextManager.setCurrentAppContext("/content/apps/cm"); // setting app context for the CM solution
The app context concept is also used (or rather leveraged) in other scenarios such as driving solution specific Building Block (BB) configurations. Since a Building Block is meant to be reusable across solutions, it exposes certain configurations that can be different for different solutions. Hence, the BB needs to behave differently depending upon the context in which it is being used or invoked. Below is an example where the Data Dictionary BB is used by two solutions – CM and ICR – and has configurations specific to each solution, lying within the solution’s specific app context – /apps/cm for CM and /apps/icr for ICR.
Original article at http://blogs.adobe.com/saket/solutions-and-the-application-context/.