NavigationHandler (Java EE 5 SDK)

javax.faces.application Class NavigationHandler

java.lang.Object
  javax.faces.application.NavigationHandler

public abstract class NavigationHandler

extends Object

A NavigationHandler is passed the outcome string returned by an application action invoked for this application, and will use this (along with related state information) to choose the view to be displayed next.

A default implementation of NavigationHandler must be provided by the JSF implementation, which will be utilized unless setNavigationHandler() is called to establish a different one. This default instance will compare the view identifier of the current view, the specified action binding, and the specified outcome against any navigation rules provided in faces-config.xml file(s). If a navigation case matches, the current view will be changed by a call to FacesContext.setViewRoot(). Note that a null outcome value will never match any navigation rule, so it can be used as an indicator that the current view should be redisplayed.

NavigationHandler

public NavigationHandler()

handleNavigation

public abstract void handleNavigation(FacesContext context,
                                      String fromAction,
                                      String outcome)

Perform navigation processing based on the state information in the specified FacesContext, plus the outcome string returned by an executed application action.

参数:

context - The FacesContext for the current request

fromAction - The action binding expression that was evaluated to retrieve the specified outcome, or null if the outcome was acquired by some other means

outcome - The logical outcome returned by a previous invoked application action (which may be null)

抛出异常:

NullPointerException - if context is null

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