org.wandora.modules.servlet

Class TemplateActionExceptionHandler

java.lang.Object

org.wandora.modules.AbstractModule

org.wandora.modules.servlet.TemplateActionExceptionHandler

All Implemented Interfaces:

Module, ActionExceptionHandler

Direct Known Subclasses:

FNGAPIExceptionHandler

public class TemplateActionExceptionHandler
extends AbstractModule
implements ActionExceptionHandler

An implementation of ActionExceptionHandler, a module that handles exceptions thrown by other actions. This handler uses a template to produce the result, much like GeneritTemplateAction. This behaves much the same way as GenericTemplateHandler, but does not extend from it, the reason being a circular dependency problem (See ActionExceptionHandler documentation for more about this).

This uses initialisation parameters templateKey, forwardRequestParameters and prefixes context. and defaultRequestParameter. in exactly the same way as GenericTemplateAction does, refer to its documentation.

Three additional variables are added to the template context. exception contains the exception that was caught, errorMessage contains the error message from the exception, this may or may not be user friendly. Finally, trace contains a stack trace of the exception.

Author:

olli

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.HashMap<java.lang.String,java.lang.String>	defaultRequestParameters
static java.lang.String	EXCEPTION_ACTION
protected java.util.ArrayList<java.lang.String>	forwardRequestParameters
protected java.lang.String	requestContextKey
protected java.util.HashMap<java.lang.String,java.lang.Object>	staticContext
protected java.lang.String	templateKey
protected TemplateManager	templateManager

Fields inherited from class org.wandora.modules.AbstractModule

autoStart, isInitialized, isRunning, logging, loggingModule, moduleManager

Constructor Summary

Constructors

Constructor and Description
TemplateActionExceptionHandler()

Method Summary

Modifier and Type	Method and Description
java.util.Collection<Module>	getDependencies(ModuleManager manager) Returns all the modules this module depends on.
protected java.util.LinkedHashMap<java.lang.String,java.lang.String>	getForwardedParameters(javax.servlet.http.HttpServletRequest req)
protected java.util.HashMap<java.lang.String,java.lang.Object>	getStaticTemplateContext()
protected Template	getTemplate(javax.servlet.http.HttpServletRequest req, ModulesServlet.HttpMethod method, ActionException exception)
protected Template	getTemplate(javax.servlet.http.HttpServletRequest req, ModulesServlet.HttpMethod method, java.lang.String action)
protected java.util.HashMap<java.lang.String,java.lang.Object>	getTemplateContext(Template template, javax.servlet.http.HttpServletRequest req, ModulesServlet.HttpMethod method, User user, ActionException ae)
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.
void	init(ModuleManager manager, java.util.HashMap<java.lang.String,java.lang.Object> settings) Initialises the module.
void	putStaticContext(java.lang.String key, java.lang.Object o)
void	start(ModuleManager manager) Starts the module.
void	stop(ModuleManager manager) Stops the module.

Methods inherited from class org.wandora.modules.AbstractModule

isInitialized, isRunning, requireLogging, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.wandora.modules.Module

isInitialized, isRunning

Field Detail

EXCEPTION_ACTION

public static final java.lang.String EXCEPTION_ACTION

See Also:

Constant Field Values

requestContextKey

protected java.lang.String requestContextKey

templateManager

protected TemplateManager templateManager

templateKey

protected java.lang.String templateKey

forwardRequestParameters

protected java.util.ArrayList<java.lang.String> forwardRequestParameters

defaultRequestParameters

protected java.util.HashMap<java.lang.String,java.lang.String> defaultRequestParameters

staticContext

protected final java.util.HashMap<java.lang.String,java.lang.Object> staticContext

Constructor Detail

TemplateActionExceptionHandler

public TemplateActionExceptionHandler()

Method Detail

putStaticContext

public void putStaticContext(java.lang.String key,
                             java.lang.Object o)

getTemplate

protected Template getTemplate(javax.servlet.http.HttpServletRequest req,
                               ModulesServlet.HttpMethod method,
                               java.lang.String action)

getDependencies

public java.util.Collection<Module> getDependencies(ModuleManager manager)
                                             throws ModuleException

Description copied from interface: Module

Returns all the modules this module depends on. This method will be called after init and the dependencies are allowed to depend on the parameters passed to init. The modules that this module depends on must be returned as a collection. In addition, if any required module is not present, a MissingDependencyException should be thrown. Typically you will use the requireModule and optionalModule methods of the manager to make sure that the modules exist and add them to the collection. requireModule will automatically throw the exception too if the module is not found whereas optionalModule does not.

Specified by:

getDependencies in interface Module

Overrides:

getDependencies in class AbstractModule

Parameters:

manager - The module manager handling this module.

Returns:

A collection of modules this module depends on.

Throws:

ModuleException

init

public void init(ModuleManager manager,
                 java.util.HashMap<java.lang.String,java.lang.Object> settings)
          throws ModuleException

Description copied from interface: Module

Initialises the module. After constructor, this is the first method called in the life cycle of a module. It should not perform anything time consuming or anything with notable outside side effects. It should only read the parameters and initialise the module so that it can later be started. Note that a module being initialised doesn't mean that it necessarily will ever be started.

A ModuleException may be thrown if something vital is missing from the parameters or they are not sensible. In some cases you may not want to throw an exception even if vital initialisation information is missing. If, for example, it is possible that the module is initialised in some other way between the init and the start method calls. A ModuleException may also be thrown at the start method if the module is still not initialised.

Specified by:

init in interface Module

Overrides:

init in class AbstractModule

Parameters:

manager - The module manager handling this module. You may keep a reference to it if needed.

Throws:

ModuleException

start

public void start(ModuleManager manager)
           throws ModuleException

Description copied from interface: Module

Starts the module. This will be called after init and getDependencies and signals that the module should now begin to perform whatever it was designed to do. This method call however should not block for long, so any time consuming tasks should be started in their own threads. You will typically get references to the required modules again in start using the findModule method of the manager and then store those references to instance variables for later use. You may throw a ModuleException if the module is not in a state where it can be started or it immediately becomes obvious that it cannot be started with the provided settings.

Specified by:

start in interface Module

Overrides:

start in class AbstractModule

Parameters:

manager - The module manager handling this module.

Throws:

ModuleException

stop

public void stop(ModuleManager manager)

Description copied from interface: Module

Stops the module. Should stop all threads used by the module, free any large data structures and perform other cleanup. It is possible that the module will be started again later with a start method call (and foregoing init and getDependencies calls). The module should be left in a state where this is possible.

Specified by:

stop in interface Module

Overrides:

stop in class AbstractModule

Parameters:

manager - The module manager handling this module.

getStaticTemplateContext

protected java.util.HashMap<java.lang.String,java.lang.Object> getStaticTemplateContext()

getForwardedParameters

protected java.util.LinkedHashMap<java.lang.String,java.lang.String> getForwardedParameters(javax.servlet.http.HttpServletRequest req)

getTemplate

protected Template getTemplate(javax.servlet.http.HttpServletRequest req,
                               ModulesServlet.HttpMethod method,
                               ActionException exception)

getTemplateContext

protected java.util.HashMap<java.lang.String,java.lang.Object> getTemplateContext(Template template,
                                                                                  javax.servlet.http.HttpServletRequest req,
                                                                                  ModulesServlet.HttpMethod method,
                                                                                  User user,
                                                                                  ActionException ae)

handleActionException

public 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

Description copied from interface: ActionExceptionHandler

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.

Specified by:

handleActionException in interface ActionExceptionHandler

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