question: public void goBack ( ) { ensureWizardIsRunning ( ) ; if ( myPrevSteps . empty ( ) ) { throw new IllegalStateException ( "Calling back on wizard without any previous pages" ) ; } ModelWizardStep currStep = mySteps . get ( myCurrIndex ) ; if ( ! currStep . canGoBack ( ) ) { throw new IllegalStateException ( "Can't call goBack on wizard when the step prevents it" ) ; } myCurrIndex = mySteps . indexOf ( myPrevSteps . pop ( ) ) ; updateNavigationProperties ( ) ; showCurrentStep ( ) ; }
target:  Returns the wizard back to the previous page. <p/> It is an error to call this if there are no previous pages to return to or on a wizard that's already finished.