org.springframework.web.servlet.mvc
Class CancellableFormController

java.lang.Object
  org.springframework.context.support.ApplicationObjectSupport
      org.springframework.web.context.support.WebApplicationObjectSupport
          org.springframework.web.servlet.support.WebContentGenerator
              org.springframework.web.servlet.mvc.AbstractController
                  org.springframework.web.servlet.mvc.BaseCommandController
                      org.springframework.web.servlet.mvc.AbstractFormController
                          org.springframework.web.servlet.mvc.SimpleFormController
                              org.springframework.web.servlet.mvc.CancellableFormController

All Implemented Interfaces:

ApplicationContextAware, ServletContextAware, Controller

public class CancellableFormController
extends SimpleFormController

Extension of SimpleFormController that supports "cancellation" of form processing. By default, this controller looks for a given parameter in the request, identified by the cancelParamKey. If this parameter is present, then the controller will return the configured cancelView, otherwise processing is passed back to the superclass.

Workflow (in addition to the superclass):

1. Call to processFormSubmission which calls isCancelRequest(javax.servlet.http.HttpServletRequest) to see if the incoming request is to cancel the current form entry. By default, isCancelRequest(javax.servlet.http.HttpServletRequest) returns true if the configured cancelParamKey exists in the request. This behavior can be overridden in subclasses.
2. If isCancelRequest(javax.servlet.http.HttpServletRequest) returns false, then the controller will delegate all processing back to SimpleFormController, otherwise it will call the onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.Object) version with all parameters. By default, that method will delegate to the onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.Object) version with just the command object, which will in turn simply return the configured cancelView. This behavior can be overridden in subclasses.

Thanks to Erwin Bolwidt for submitting the original prototype of such a cancellable form controller!

Since:

1.2.3

Author:

Rob Harrop, Juergen Hoeller

See Also:

setCancelParamKey(java.lang.String), setCancelView(java.lang.String), isCancelRequest(javax.servlet.http.HttpServletRequest), onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, Object)

Field Summary

Fields inherited from class org.springframework.web.servlet.mvc.BaseCommandController

DEFAULT_COMMAND_NAME

Fields inherited from class org.springframework.web.servlet.support.WebContentGenerator

METHOD_GET, METHOD_HEAD, METHOD_POST

Fields inherited from class org.springframework.context.support.ApplicationObjectSupport

logger

Constructor Summary

CancellableFormController()

Method Summary

String	getCancelParamKey() Return the key of the request parameter used to identify a cancel request.
String	getCancelView() Gets the name of the cancel view.
protected boolean	isCancelRequest(HttpServletRequest request) Determine whether the incoming request is a request to cancel the processing of the current form.
protected boolean	isFormSubmission(HttpServletRequest request) Consider an explicit cancel request as a form submission too.
protected ModelAndView	onCancel(HttpServletRequest request, HttpServletResponse response, Object command) Callback method for handling a cancel request.
protected ModelAndView	onCancel(Object command) Simple onCancel version.
protected ModelAndView	processFormSubmission(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) This implementation first checks to see if the incoming is a cancel request, through a call to isCancelRequest(javax.servlet.http.HttpServletRequest).
void	setCancelParamKey(String cancelParamKey) Set the key of the request parameter used to identify a cancel request.
void	setCancelView(String cancelView) Sets the name of the cancel view.
protected boolean	suppressValidation(HttpServletRequest request, Object command) Suppress validation for an explicit cancel request too.

Methods inherited from class org.springframework.web.servlet.mvc.SimpleFormController

doSubmitAction, getFormView, getSuccessView, isFormChangeRequest, isFormChangeRequest, onFormChange, onFormChange, onSubmit, onSubmit, onSubmit, referenceData, referenceData, setFormView, setSuccessView, showForm, showForm

Methods inherited from class org.springframework.web.servlet.mvc.AbstractFormController

currentFormObject, formBackingObject, getCommand, getErrorsForNewForm, getFormSessionAttributeName, getFormSessionAttributeName, handleInvalidSubmit, handleRequestInternal, isBindOnNewForm, isSessionForm, onBindOnNewForm, onBindOnNewForm, setBindOnNewForm, setSessionForm, showForm, showForm, showNewForm

Methods inherited from class org.springframework.web.servlet.mvc.BaseCommandController

bindAndValidate, checkCommand, createBinder, createCommand, getBindingErrorProcessor, getCommandClass, getCommandName, getMessageCodesResolver, getPropertyEditorRegistrars, getValidator, getValidators, initApplicationContext, initBinder, isValidateOnBinding, onBind, onBind, onBindAndValidate, prepareBinder, setBindingErrorProcessor, setCommandClass, setCommandName, setMessageCodesResolver, setPropertyEditorRegistrar, setPropertyEditorRegistrars, setValidateOnBinding, setValidator, setValidators, suppressBinding, suppressValidation, suppressValidation, useDirectFieldAccess

Methods inherited from class org.springframework.web.servlet.mvc.AbstractController

handleRequest, isSynchronizeOnSession, setSynchronizeOnSession

Methods inherited from class org.springframework.web.servlet.support.WebContentGenerator

applyCacheSeconds, applyCacheSeconds, cacheForSeconds, cacheForSeconds, checkAndPrepare, checkAndPrepare, getCacheSeconds, getSupportedMethods, isRequireSession, isUseCacheControlHeader, isUseExpiresHeader, preventCaching, setCacheSeconds, setRequireSession, setSupportedMethods, setUseCacheControlHeader, setUseExpiresHeader

Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport

getServletContext, getTempDir, getWebApplicationContext, isContextRequired, setServletContext

Methods inherited from class org.springframework.context.support.ApplicationObjectSupport

getApplicationContext, getMessageSourceAccessor, requiredContextClass, setApplicationContext

Methods inherited from class java.lang.Object

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

Constructor Detail

CancellableFormController

public CancellableFormController()

Method Detail

setCancelParamKey

public final void setCancelParamKey(String cancelParamKey)

Set the key of the request parameter used to identify a cancel request. Default is "_cancel".

The parameter is recognized both when sent as a plain parameter ("_cancel") or when triggered by an image button ("_cancel.x").

getCancelParamKey

public final String getCancelParamKey()

Return the key of the request parameter used to identify a cancel request.

setCancelView

public final void setCancelView(String cancelView)

Sets the name of the cancel view.

getCancelView

public final String getCancelView()

Gets the name of the cancel view.

isFormSubmission

protected boolean isFormSubmission(HttpServletRequest request)

Consider an explicit cancel request as a form submission too.

Overrides:

isFormSubmission in class AbstractFormController

Parameters:

request - current HTTP request

Returns:

if the request represents a form submission

See Also:

isCancelRequest(javax.servlet.http.HttpServletRequest)

suppressValidation

protected boolean suppressValidation(HttpServletRequest request,
                                     Object command)

Suppress validation for an explicit cancel request too.

Overrides:

suppressValidation in class SimpleFormController

Parameters:

request - current HTTP request

command - the command object to validate

Returns:

whether to suppress validation for the given request

See Also:

isCancelRequest(javax.servlet.http.HttpServletRequest)

processFormSubmission

protected ModelAndView processFormSubmission(HttpServletRequest request,
                                             HttpServletResponse response,
                                             Object command,
                                             BindException errors)
                                      throws Exception

This implementation first checks to see if the incoming is a cancel request, through a call to isCancelRequest(javax.servlet.http.HttpServletRequest). If so, control is passed to onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.Object); otherwise, control is passed up to SimpleFormController.processFormSubmission(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.Object, org.springframework.validation.BindException).

Overrides:

processFormSubmission in class SimpleFormController

Parameters:

request - current servlet request

response - current servlet response

command - form object with request parameters bound onto it

errors - holder without errors (subclass can add errors if it wants to)

Returns:

the prepared model and view, or null

Throws:

Exception - in case of errors

See Also:

isCancelRequest(javax.servlet.http.HttpServletRequest), onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, Object), SimpleFormController.processFormSubmission(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.Object, org.springframework.validation.BindException)

isCancelRequest

protected boolean isCancelRequest(HttpServletRequest request)

Determine whether the incoming request is a request to cancel the processing of the current form.

By default, this method returns true if a parameter matching the configured cancelParamKey is present in the request, otherwise it returns false. Subclasses may override this method to provide custom logic to detect a cancel request.

The parameter is recognized both when sent as a plain parameter ("_cancel") or when triggered by an image button ("_cancel.x").

Parameters:

request - current HTTP request

See Also:

setCancelParamKey(java.lang.String), PARAM_CANCEL

onCancel

protected ModelAndView onCancel(HttpServletRequest request,
                                HttpServletResponse response,
                                Object command)
                         throws Exception

Callback method for handling a cancel request. Called if isCancelRequest(javax.servlet.http.HttpServletRequest) returns true.

Default implementation delegates to onCancel(Object) to return the configured cancelView. Subclasses may override either of the two methods to build a custom ModelAndView that may contain model parameters used in the cancel view.

If you simply want to move the user to a new view and you don't want to add additional model parameters, use setCancelView(String) rather than overriding an onCancel method.

Parameters:

request - current servlet request

response - current servlet response

command - form object with request parameters bound onto it

Returns:

the prepared model and view, or null

Throws:

Exception - in case of errors

See Also:

isCancelRequest(javax.servlet.http.HttpServletRequest), onCancel(Object), setCancelView(java.lang.String)

onCancel

protected ModelAndView onCancel(Object command)
                         throws Exception

Simple onCancel version. Called by the default implementation of the onCancel version with all parameters.

Default implementation returns eturns the configured cancelView. Subclasses may override this method to build a custom ModelAndView that may contain model parameters used in the cancel view.

If you simply want to move the user to a new view and you don't want to add additional model parameters, use setCancelView(String) rather than overriding an onCancel method.

Parameters:

command - form object with request parameters bound onto it

Returns:

the prepared model and view, or null

Throws:

Exception - in case of errors

See Also:

onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, Object), setCancelView(java.lang.String)