org.springframework.web.servlet.mvc
Class SimpleFormController

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

All Implemented Interfaces:

ApplicationContextAware, Controller

public class SimpleFormController

extends AbstractFormController

Concrete FormController implementation that provides configurable form and success views, and an onSubmit chain for convenient overriding. Automatically resubmits to the form view in case of validation errors, and renders the success view in case of a valid submission.

The workflow of this Controller does not differ much from the one described in the AbstractFormController. The difference is that you do not need to implement showForm and processFormSubmission: A form view and a success view can be configured declaratively.

Workflow (in addition to the superclass):

1. Call to processFormSubmission which inspects the Errors object to see if any errors have occurred during binding and validation.
2. If errors occured, the controller will return the configured formView, showing the form again (possibly rendering according error messages).
3. If isFormChangeRequest is overridden and returns true for the given request, the controller will return the formView too. In that case, the controller will also suppress validation. This is intended for requests that change the structure of the form, which should not cause validation and show the form in any case.
4. If no errors occurred, the controller will call onSubmit using all parameters, which in case of the default implementation delegates to onSubmit with just the command object. The default implementation of the latter method will return the configured successView. Consider implementing doSubmitAction(java.lang.Object) doSubmitAction for simply performing a submit action and rendering the success view.

The submit behavior can be customized by overriding one of the onSubmit methods. Submit actions can also perform custom validation if necessary (typically database-driven checks), calling showForm in case of validation errors to show the form view again.

Exposed configuration properties (and those defined by superclass):

name	default	description
formView	null	Indicates what view to use when the user asks for a new form or when validation errors have occurred on form submission.
successView	null	Indicates what view to use when successful form submissions have occurred. Such a success view could e.g. display a submission summary. More sophisticated actions can be implemented by overriding one of the onSubmit() methods.

Since:

05.05.2003

Author:

Juergen Hoeller

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

HEADER_CACHE_CONTROL, HEADER_EXPIRES, HEADER_PRAGMA, METHOD_GET, METHOD_POST

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

logger

Constructor Summary

SimpleFormController()
Create a new SimpleFormController.

Method Summary

protected void	doSubmitAction(Object command) Template method for submit actions.
String	getFormView() Return the name of the view that should be used for form display.
String	getSuccessView() Return the name of the view that should be shown on successful submit.
protected boolean	isFormChangeRequest(HttpServletRequest request) Determine whether the given request is a form change request.
protected ModelAndView	onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) Submit callback with all parameters.
protected ModelAndView	onSubmit(Object command) Simplest onSubmit version.
protected ModelAndView	onSubmit(Object command, BindException errors) Simpler onSubmit version.
protected ModelAndView	processFormSubmission(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) This implementation calls showForm in case of errors, and delegates to onSubmit's full version else.
protected Map	referenceData(HttpServletRequest request) Create a reference data map for the given request.
protected Map	referenceData(HttpServletRequest request, Object command, Errors errors) Create a reference data map for the given request and command, consisting of bean name/bean instance pairs as expected by ModelAndView.
void	setFormView(String formView) Set the name of the view that should be used for form display.
void	setSuccessView(String successView) Set the name of the view that should be shown on successful submit.
protected ModelAndView	showForm(HttpServletRequest request, HttpServletResponse response, BindException errors) This implementation shows the configured form view.
protected boolean	suppressValidation(HttpServletRequest request) This implementation delegates to isFormChangeRequest: A form change request changes the appearance of the form and should not get validated but just show the new form.

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

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

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

bindAndValidate, checkCommand, createBinder, createCommand, getCommandClass, getCommandName, getMessageCodesResolver, getValidator, getValidators, initApplicationContext, initBinder, isValidateOnBinding, onBind, onBind, onBindAndValidate, setCommandClass, setCommandName, setMessageCodesResolver, setValidateOnBinding, setValidator, setValidators

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

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

SimpleFormController

public SimpleFormController()

Create a new SimpleFormController.

Subclasses should set the following properties, either in the constructor or via a BeanFactory: commandName, commandClass, sessionForm, formView, successView. Note that commandClass doesn't need to be set when overriding formBackingObject, as this determines the class anyway.

See Also:

BaseCommandController.setCommandClass(java.lang.Class), BaseCommandController.setCommandName(java.lang.String), AbstractFormController.setSessionForm(boolean), setFormView(java.lang.String), setSuccessView(java.lang.String), AbstractFormController.formBackingObject(javax.servlet.http.HttpServletRequest)

Method Detail

setFormView

public final void setFormView(String formView)

Set the name of the view that should be used for form display.

getFormView

public final String getFormView()

Return the name of the view that should be used for form display.

setSuccessView

public final void setSuccessView(String successView)

Set the name of the view that should be shown on successful submit.

getSuccessView

public final String getSuccessView()

Return the name of the view that should be shown on successful submit.

referenceData

protected Map referenceData(HttpServletRequest request,
                            Object command,
                            Errors errors)
                     throws Exception

Create a reference data map for the given request and command, consisting of bean name/bean instance pairs as expected by ModelAndView.

Default implementation delegates to referenceData(request). Subclasses can override this to set reference data used in the view.

Overrides:

referenceData in class AbstractFormController

Parameters:

request - current HTTP request

command - form object with request parameters bound onto it

errors - validation errors holder

Returns:

a Map with reference data entries, or null if none

Throws:

Exception - in case of invalid state or arguments

See Also:

ModelAndView

referenceData

protected Map referenceData(HttpServletRequest request)
                     throws Exception

Create a reference data map for the given request. Called by referenceData version with all parameters.

Default implementation returns null. Subclasses can override this to set reference data used in the view.

Parameters:

request - current HTTP request

Returns:

a Map with reference data entries, or null if none

Throws:

Exception - in case of invalid state or arguments

See Also:

referenceData(HttpServletRequest, Object, Errors), ModelAndView

showForm

protected ModelAndView showForm(HttpServletRequest request,
                                HttpServletResponse response,
                                BindException errors)
                         throws Exception

This implementation shows the configured form view. Can be called within onSubmit implementations, to redirect back to the form in case of custom validation errors (i.e. not determined by the validator).

Specified by:

showForm in class AbstractFormController

Parameters:

request - current HTTP request

response - current HTTP response

errors - validation errors holder

Returns:

the prepared form view, or null if handled directly

Throws:

Exception - in case of invalid state or arguments

See Also:

setFormView(java.lang.String)

suppressValidation

protected final boolean suppressValidation(HttpServletRequest request)

This implementation delegates to isFormChangeRequest: A form change request changes the appearance of the form and should not get validated but just show the new form.

Overrides:

suppressValidation in class BaseCommandController

Parameters:

request - current HTTP request

Returns:

whether to suppress validation for the given request

See Also:

isFormChangeRequest(javax.servlet.http.HttpServletRequest)

processFormSubmission

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

This implementation calls showForm in case of errors, and delegates to onSubmit's full version else.

This can only be overridden to check for an action that should be executed without respect to binding errors, like a cancel action. To just handle successful submissions without binding errors, override one of the onSubmit methods.

Specified by:

processFormSubmission in class AbstractFormController

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:

showForm(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, org.springframework.validation.BindException), onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException)

isFormChangeRequest

protected boolean isFormChangeRequest(HttpServletRequest request)

Determine whether the given request is a form change request. A form change request changes the appearance of the form and should always show the new form, without validation.

Gets called by suppressValidation and processFormSubmission. Consequently, this single method determines to suppress validation and to show the form view in any case.

Parameters:

request - current HTTP request

Returns:

whether the given request is a form change request

See Also:

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

onSubmit

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

Submit callback with all parameters. Called in case of submit without errors reported by the registered validator respectively on every submit if no validator.

Default implementation delegates to onSubmit(Object, BindException). For simply performing a submit action and rendering the specified success view, consider implementing doSubmitAction rather than an onSubmit version.

Subclasses can override this to provide custom submission handling like storing the object to the database. Implementations can also perform custom validation and call showForm to return to the form. Do not implement multiple onSubmit methods: In that case, just this method will be called by the controller.

Call errors.getModel() to populate the ModelAndView model with the command and the Errors instance, under the specified command name, as expected by the "spring:bind" tag.

Parameters:

request - current servlet request

response - current servlet response

command - form object with request parameters bound onto it

errors - Errors instance 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:

onSubmit(Object, BindException), doSubmitAction(java.lang.Object), showForm(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, org.springframework.validation.BindException), Errors, BindException.getModel()

onSubmit

protected ModelAndView onSubmit(Object command,
                                BindException errors)
                         throws Exception

Simpler onSubmit version. Called by the default implementation of the onSubmit version with all parameters.

Default implementation calls onSubmit(command), using the returned ModelAndView if actually implemented in a subclass. Else, the default behavior is applied: rendering the success view with the command and Errors instance as model.

Subclasses can override this to provide custom submission handling that does not need request and response.

Call errors.getModel() to populate the ModelAndView model with the command and the Errors instance, under the specified command name, as expected by the "spring:bind" tag.

Parameters:

command - form object with request parameters bound onto it

errors - Errors instance without errors

Returns:

the prepared model and view, or null

Throws:

Exception - in case of errors

See Also:

onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException), onSubmit(Object), setSuccessView(java.lang.String), Errors, BindException.getModel()

onSubmit

protected ModelAndView onSubmit(Object command)
                         throws Exception

Simplest onSubmit version. Called by the default implementation of the onSubmit version with command and BindException parameters.

This implementation calls doSubmitAction and returns null as ModelAndView, making the calling onSubmit method perform its default rendering of the success view.

Subclasses can override this to provide custom submission handling that just depends on the command object. It's preferable to use either onSubmit(command, errors) or doSubmitAction(command), though: Use the former when you want to build your own ModelAndView; use the latter when you want to perform an action and forward to the successView.

Parameters:

command - form object with request parameters bound onto it

Returns:

the prepared model and view, or null for default (i.e. successView)

Throws:

Exception - in case of errors

See Also:

onSubmit(Object, BindException), doSubmitAction(java.lang.Object), setSuccessView(java.lang.String)

doSubmitAction

protected void doSubmitAction(Object command)
                       throws Exception

Template method for submit actions. Called by the default implementation of the simplest onSubmit version.

This is the preferred submit callback to implement if you want to perform an action (like storing changes to the database) and then render the success view with the command and Errors instance as model. You don't need to care about the success ModelAndView here.

Parameters:

command - form object with request parameters bound onto it

Throws:

Exception - in case of errors

See Also:

onSubmit(Object), setSuccessView(java.lang.String)