URL Task Flow vs. WSRP Portlets
By Frank Nimphius-Oracle on Mar 19, 2012
A URL task flow is bounded task flow that is deployed as a stand-alone Java EE application on a remote server with its URL Invoke property set to url-invoke-allowed. The URL task flow is accessed either from a direct browser GET request or, when called from another ADF application, through the task flow call activity.
For more information about how to invoke URL task flows from a task flow call activity see chapter 15.6.4 How to Call a Bounded Task Flow Using a URL of the Oracle Fusion Middleware Fusion Developer's Guide for Oracle Application Development Framework at
Compared to WRSP portlets, URL task flows in Oracle JDeveloper 11g R1 and R2 have a functional limitation in that they cannot be embedded as a region on a page but require the calling ADF application to navigate off to another application and page. The difference between a URL task flow call using the task flow call activity and a simple redirect to a remote Java EE application is that the URL task flow has a state token attached that allows to restore the state of the calling application upon task flow return.
A use case for a URL task flow call activity is a "yellow page lookup" scenario in which different ADF applications use an URL task flow to lookup people, products or similar to return a selected value to the calling application.
Note that URL task flow calls need to be performed from a bounded or unbounded top level task flow of the calling application. If called from a region (using the parent call activity) in a page, the region state is not recovered upon task flow return.
ADF developers recently have identified URL task flows as an architecture pattern to partition their ADF applications into independently deployed Java EE applications. While this sounds like a desirable use of the URL task flow feature, it is not possible to achieve for as long as URL task flows don't render as an ADF region.