org.springframework.web.jsf
Class DecoratingNavigationHandler

java.lang.Object
  javax.faces.application.NavigationHandler
      org.springframework.web.jsf.DecoratingNavigationHandler

public abstract class DecoratingNavigationHandler
extends NavigationHandler

Base class for JSF NavigationHandler implementations that want to be capable of decorating an original NavigationHandler.

Supports the standard JSF style of decoration (through a constructor argument) as well as an overloaded handleNavigation method with explicit NavigationHandler argument (passing in the original NavigationHandler). Subclasses are forced to implement this overloaded handleNavigation method. Standard JSF invocations will automatically delegate to the overloaded method, with the constructor-injected NavigationHandler as argument.

Since:

1.2.7

Author:

Juergen Hoeller

See Also:

DelegatingNavigationHandlerProxy

Constructor Summary

protected	DecoratingNavigationHandler() Create a DecoratingNavigationHandler without fixed original NavigationHandler.
protected	DecoratingNavigationHandler(NavigationHandler originalNavigationHandler) Create a DecoratingNavigationHandler with fixed original NavigationHandler.

Method Summary

protected void	callNextHandlerInChain(FacesContext facesContext, String fromAction, String outcome, NavigationHandler originalNavigationHandler) Method to be called by subclasses when intending to delegate to the next handler in the NavigationHandler chain.
NavigationHandler	getDecoratedNavigationHandler() Return the fixed original NavigationHandler decorated by this handler, if any (that is, if passed in through the constructor).
void	handleNavigation(FacesContext facesContext, String fromAction, String outcome) This implementation of the standard JSF handleNavigation method delegates to the overloaded variant, passing in constructor-injected NavigationHandler as argument.
abstract void	handleNavigation(FacesContext facesContext, String fromAction, String outcome, NavigationHandler originalNavigationHandler) Special handleNavigation variant with explicit NavigationHandler argument.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DecoratingNavigationHandler

protected DecoratingNavigationHandler()

Create a DecoratingNavigationHandler without fixed original NavigationHandler.

DecoratingNavigationHandler

protected DecoratingNavigationHandler(NavigationHandler originalNavigationHandler)

Create a DecoratingNavigationHandler with fixed original NavigationHandler.

Parameters:

originalNavigationHandler - the original NavigationHandler to decorate

Method Detail

getDecoratedNavigationHandler

public final NavigationHandler getDecoratedNavigationHandler()

Return the fixed original NavigationHandler decorated by this handler, if any (that is, if passed in through the constructor).

handleNavigation

public final void handleNavigation(FacesContext facesContext,
                                   String fromAction,
                                   String outcome)

This implementation of the standard JSF handleNavigation method delegates to the overloaded variant, passing in constructor-injected NavigationHandler as argument.

Specified by:

handleNavigation in class NavigationHandler

See Also:

handleNavigation(javax.faces.context.FacesContext, String, String, javax.faces.application.NavigationHandler)

handleNavigation

public abstract void handleNavigation(FacesContext facesContext,
                                      String fromAction,
                                      String outcome,
                                      NavigationHandler originalNavigationHandler)

Special handleNavigation variant with explicit NavigationHandler argument. Either called directly, by code with an explicit original handler, or called from the standard handleNavigation method, as plain JSF-defined NavigationHandler.

Implementations should invoke callNextHandlerInChain to delegate to the next handler in the chain. This will always call the most appropriate next handler (see callNextHandlerInChain javadoc). Alternatively, the decorated NavigationHandler or the passed-in original NavigationHandler can also be called directly; however, this is not as flexible in terms of reacting to potential positions in the chain.

Parameters:

facesContext - the current JSF context

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)

originalNavigationHandler - the original NavigationHandler, or null if none

See Also:

callNextHandlerInChain(javax.faces.context.FacesContext, java.lang.String, java.lang.String, javax.faces.application.NavigationHandler)

callNextHandlerInChain

protected final void callNextHandlerInChain(FacesContext facesContext,
                                            String fromAction,
                                            String outcome,
                                            NavigationHandler originalNavigationHandler)

Method to be called by subclasses when intending to delegate to the next handler in the NavigationHandler chain. Will always call the most appropriate next handler, either the decorated NavigationHandler passed in as constructor argument or the original NavigationHandler as passed into this method - according to the position of this instance in the chain.

Will call the decorated NavigationHandler specified as constructor argument, if any. In case of a DecoratingNavigationHandler as target, the original NavigationHandler as passed into this method will be passed on to the next element in the chain: This ensures propagation of the original handler that the last element in the handler chain might delegate back to. In case of a standard NavigationHandler as target, the original handler will simply not get passed on; no delegating back to the original is possible further down the chain in that scenario.

If no decorated NavigationHandler specified as constructor argument, this instance is the last element in the chain. Hence, this method will call the original NavigationHandler as passed into this method. If no original NavigantionHandler has been passed in (for example if this instance is the last element in a chain with standard NavigationHandlers as earlier elements), this method corresponds to a no-op.

Parameters:

facesContext - the current JSF context

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)

originalNavigationHandler - the original NavigationHandler, or null if none