org.springframework.web.servlet.mvc
Class CancellableFormController

java.lang.Object
  extended by org.springframework.context.support.ApplicationObjectSupport
      extended by org.springframework.web.context.support.WebApplicationObjectSupport
          extended by org.springframework.web.servlet.support.WebContentGenerator
              extended by org.springframework.web.servlet.mvc.AbstractController
                  extended by org.springframework.web.servlet.mvc.BaseCommandController
                      extended by org.springframework.web.servlet.mvc.AbstractFormController
                          extended by org.springframework.web.servlet.mvc.SimpleFormController
                              extended by 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, getWebBindingInitializer, initApplicationContext, initBinder, isValidateOnBinding, onBind, onBind, onBindAndValidate, prepareBinder, setBindingErrorProcessor, setCommandClass, setCommandName, setMessageCodesResolver, setPropertyEditorRegistrar, setPropertyEditorRegistrars, setValidateOnBinding, setValidator, setValidators, setWebBindingInitializer, 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, isUseCacheControlNoStore, isUseExpiresHeader, preventCaching, setCacheSeconds, setRequireSession, setSupportedMethods, setUseCacheControlHeader, setUseCacheControlNoStore, setUseExpiresHeader
 
Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport
getServletContext, getTempDir, getWebApplicationContext, initApplicationContext, initServletContext, 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)


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