org.wandora.modules.servlet

Interface ActionExceptionHandler

All Superinterfaces:

Module

All Known Implementing Classes:

FNGAPIExceptionHandler, TemplateActionExceptionHandler

public interface ActionExceptionHandler
extends Module

An interface for handlers that can take care of ActionExceptions thrown when handling an HTTP request. By including a module that implements this interface, GenericContext will automatically use it whenever an ActionException inside it occurs. Note that the root servlet does not (necessarily) perform similarly. If you want to include custom ActionException handling, you should use a context for all your actions. GenericContext can be used as is for this purpose.

See TemplateActionExceptionHandler for a generic implementation of this using templates.

Implementations of this should not extends AbstractAction, or if they do, they need to take special care about dependency handling. The reason is that this will easily cause a circular dependency. AbstractAction will require a ServletModule. ServletModules, which GenericContext implements, may then optionally require an ActionExceptionHandler. If that is an AbstractAction, it will again look for a ServletModule and so on. So if you do extend AbstractAction, you will need to override getDependencies to break the circular dependency problem.

Author:

olli

Method Summary

Modifier and Type	Method and Description
boolean	handleActionException(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp, ModulesServlet.HttpMethod method, User user, ActionException ae) Handles an exception that occurred when handling an HTTP request.

Methods inherited from interface org.wandora.modules.Module

getDependencies, init, isInitialized, isRunning, start, stop

Method Detail

handleActionException

boolean handleActionException(javax.servlet.http.HttpServletRequest req,
                              javax.servlet.http.HttpServletResponse resp,
                              ModulesServlet.HttpMethod method,
                              User user,
                              ActionException ae)
                       throws javax.servlet.ServletException,
                              java.io.IOException,
                              ActionException

Handles an exception that occurred when handling an HTTP request. The ActionException itself should contain the action where it occurred. The return value will act as if the original action return it. In other words, true indicates that the request was handled while false means that the context, or root servlet, should continue giving other actions a chance to handle it. Note that even returning false indicates that you have handled the exception in some way. If you decide not to handle the exception at all, rethrow it in the handler instead of returning either true or false. That, or any other exception thrown, will not be caught by this same handler, but may be caught by another handler higher up in the context tree.

Parameters:

req - The HTTP request.

resp - The HTTP request where the response can be written.

method - The HTTP method used with the request.

user - The authenticated user, or null if not applicable.

ae - The ActionException that caused this to be called.

Returns:

True if the action has been handled, false if other actions should still try to handle it.

Throws:

javax.servlet.ServletException

java.io.IOException

ActionException