Base class for controller logic, exception handlers, and state associated with a particular web directory path. The class is configured through the @Jpf.Controller annotation.

When a page flow request (the page flow URI itself, or any ".do" or page URI in the directory path), arrives, an instance of the associated PageFlowController class is set as the current page flow, and remains stored in the session until a different one becomes active ("long lived" page flows stay in the session indefinitely; see longLived on @Jpf.Controller ).

The page flow class handles actions that are most commonly raised by user interaction with pages. The actions are handled by action methods or action annotations that determine the next URI to be displayed, after optionally performing arbitrary logic.

If the PageFlowController is a "nested page flow" ( nested is set to true on @Jpf.Controller ), then this is a reusable, modular flow that can be "nested" during other flows. It has entry points (actions with optional form bean arguments), and exit points ( @Jpf.Forward , @Jpf.SimpleAction , or @Jpf.ConditionalForward annotations that have returnAction attributes).

The page flow class also handles exceptions thrown by actions or during page execution (see catches on @Jpf.Controller ). Unhandled exceptions are handled in order by declared SharedFlowController s (see sharedFlowRefs on @Jpf.Controller ).

Properties in the current page flow instance can be accessed from JSP 2.0-style expressions like this one: ${pageFlow.someProperty}.

There may only be one page flow in any package.