1.5.2. How it works
The game begins in the
numberGuess.jspx view. When the page is first displayed, the pages.xml configuration activates a conversation and associates it with the numberGuess pageflow. The pageflow starts with a start-page tag (a wait state), so the numberGuess.xhtml is rendered.
The view references the
numberGuess component, which causes a new instance to be created and stored in the conversation. the @Create method is called, initializing the game's state. The view displays an h:form, which allows the user to edit #{numberGuess.currentGuess}.
The "Guess" button triggers the
guess action. Seam refers to the pageflow to handle the action, and the pageflow invokes #{numberGuess.guess} (which updates the guess count and highest/lowest suggestions in the numberGuess component), and transitions to the evaluateGuess state.
The
evaluateGuess state checks the value of #{numberGuess.correctGuess} and transitions to either the win or evaluatingRemainingGuesses state. Assuming the number was incorrect, the pageflow transitions to evaluatingRemainingGuesses. This is also a decision state, which tests the #{numberGuess.lastGuess} state to determine whether or not the user is allowed further guesses. If further guesses are allowed (lastGuess is false), we transition back to the original displayGuess state. Since this is a page state, the associated page /numberGuess.jspx is displayed. This page also contains a redirect element, so Seam sends a redirect to the user's browser, which begins the process again.
If on a future request either the
win or the lose transition were invoked, the user would be taken to /win.jspx or /lose.jspx respectively. Both states specify that Seam should end the conversation, stop holding game and pageflow state, and redirect the user to the final page.
The numberguess example also contains Give up and Cheat buttons. The pageflow state for both actions is relatively easy to trace, so we do not describe it here. Pay particular attention to the
cheat transition, which loads a sub-process to handle that particular flow. Although in this application this process is superfluous, this demonstrates how complex pageflows can be broken down into smaller, simpler structures to make them easier to understand.
