|
|
Spring Framework example source code file (SimpleFormController.java)
This example Spring Framework source code file (SimpleFormController.java) is included in the DevDaily.com
"Java Source Code
Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.
The Spring Framework SimpleFormController.java source code
/*
* Copyright 2002-2007 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.servlet.mvc;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.validation.BindException;
import org.springframework.validation.Errors;
import org.springframework.web.servlet.ModelAndView;
/**
* <p>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.</p>
*
* <p>The workflow of this Controller does not differ much from the one described
* in the {@link AbstractFormController AbstractFormController}. The difference
* is that you do not need to implement {@link #showForm showForm} and
* {@link #processFormSubmission processFormSubmission}: A form view and a
* success view can be configured declaratively.</p>
*
* <p>Workflow
* (<a href="AbstractFormController.html#workflow">in addition to the superclass):
* <ol>
* <li>Call to {@link #processFormSubmission processFormSubmission} which inspects
* the {@link org.springframework.validation.Errors Errors} object to see if
* any errors have occurred during binding and validation.</li>
* <li>If errors occured, the controller will return the configured formView,
* showing the form again (possibly rendering according error messages).</li>
* <li>If {@link #isFormChangeRequest 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. Before returning the formView,
* the controller will invoke {@link #onFormChange}, giving sub-classes a chance
* to make modification to the command object.
* This is intended for requests that change the structure of the form,
* which should not cause validation and show the form in any case.</li>
* <li>If no errors occurred, the controller will call
* {@link #onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException) onSubmit}
* using all parameters, which in case of the default implementation delegates to
* {@link #onSubmit(Object, BindException) onSubmit} with just the command object.
* The default implementation of the latter method will return the configured
* <code>successView. Consider implementing {@link #doSubmitAction} doSubmitAction
* for simply performing a submit action and rendering the success view.</li>
* </ol>
* </p>
*
* <p>The submit behavior can be customized by overriding one of the
* {@link #onSubmit onSubmit} methods. Submit actions can also perform
* custom validation if necessary (typically database-driven checks), calling
* {@link #showForm(HttpServletRequest, HttpServletResponse, BindException) showForm}
* in case of validation errors to show the form view again.</p>
*
* <p>Exposed configuration properties
* (<a href="AbstractFormController.html#config">and those defined by superclass):
* <table border="1">
* <tr>
* <td>name |
* <td>default
* <td>description
* </tr>
* <tr>
* <td>formView
* <td>null
* <td>Indicates what view to use when the user asks for a new form
* or when validation errors have occurred on form submission.</td>
* </tr>
* <tr>
* <td>successView
* <td>null
* <td>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 {@link #onSubmit(Object) onSubmit()} methods.</td>
* </tr>
* <table>
* </p>
*
* @author Juergen Hoeller
* @author Rob Harrop
* @since 05.05.2003
*/
public class SimpleFormController extends AbstractFormController {
private String formView;
private String successView;
/**
* Create a new SimpleFormController.
* <p>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
* <code>formBackingObject, as this determines the class anyway.
* @see #setCommandClass
* @see #setCommandName
* @see #setSessionForm
* @see #setFormView
* @see #setSuccessView
* @see #formBackingObject
*/
public SimpleFormController() {
// AbstractFormController sets default cache seconds to 0.
super();
}
/**
* Set the name of the view that should be used for form display.
*/
public final void setFormView(String formView) {
this.formView = formView;
}
/**
* Return the name of the view that should be used for form display.
*/
public final String getFormView() {
return this.formView;
}
/**
* Set the name of the view that should be shown on successful submit.
*/
public final void setSuccessView(String successView) {
this.successView = successView;
}
/**
* Return the name of the view that should be shown on successful submit.
*/
public final String getSuccessView() {
return this.successView;
}
/**
* This implementation shows the configured form view, delegating to the analogous
* {@link #showForm(HttpServletRequest, HttpServletResponse, BindException, Map)}
* variant with a "controlModel" argument.
* <p>Can be called within
* {@link #onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException)}
* implementations, to redirect back to the form in case of custom validation errors
* (errors not determined by the validator).
* <p>Can be overridden in subclasses to show a custom view, writing directly
* to the response or preparing the response before rendering a view.
* <p>If calling showForm with a custom control model in subclasses, it's preferable
* to override the analogous showForm version with a controlModel argument
* (which will handle both standard form showing and custom form showing then).
* @see #setFormView
* @see #showForm(HttpServletRequest, HttpServletResponse, BindException, Map)
*/
protected ModelAndView showForm(
HttpServletRequest request, HttpServletResponse response, BindException errors)
throws Exception {
return showForm(request, response, errors, null);
}
/**
* This implementation shows the configured form view.
* <p>Can be called within
* {@link #onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException)}
* implementations, to redirect back to the form in case of custom validation errors
* (errors not determined by the validator).
* <p>Can be overridden in subclasses to show a custom view, writing directly
* to the response or preparing the response before rendering a view.
* @param request current HTTP request
* @param errors validation errors holder
* @param controlModel model map containing controller-specific control data
* (e.g. current page in wizard-style controllers or special error message)
* @return the prepared form view
* @throws Exception in case of invalid state or arguments
* @see #setFormView
*/
protected ModelAndView showForm(
HttpServletRequest request, HttpServletResponse response, BindException errors, Map controlModel)
throws Exception {
return showForm(request, errors, getFormView(), controlModel);
}
/**
* Create a reference data map for the given request and command,
* consisting of bean name/bean instance pairs as expected by ModelAndView.
* <p>The default implementation delegates to {@link #referenceData(HttpServletRequest)}.
* Subclasses can override this to set reference data used in the view.
* @param request current HTTP request
* @param command form object with request parameters bound onto it
* @param errors validation errors holder
* @return a Map with reference data entries, or <code>null if none
* @throws Exception in case of invalid state or arguments
* @see ModelAndView
*/
protected Map referenceData(HttpServletRequest request, Object command, Errors errors) throws Exception {
return referenceData(request);
}
/**
* Create a reference data map for the given request.
* Called by the {@link #referenceData(HttpServletRequest, Object, Errors)}
* variant with all parameters.
* <p>The default implementation returns null.
* Subclasses can override this to set reference data used in the view.
* @param request current HTTP request
* @return a Map with reference data entries, or <code>null if none
* @throws Exception in case of invalid state or arguments
* @see #referenceData(HttpServletRequest, Object, Errors)
* @see ModelAndView
*/
protected Map referenceData(HttpServletRequest request) throws Exception {
return null;
}
/**
* This implementation calls
* {@link #showForm(HttpServletRequest, HttpServletResponse, BindException)}
* in case of errors, and delegates to the full
* {@link #onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException)}'s
* variant else.
* <p>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 <code>onSubmit
* methods or {@link #doSubmitAction}.
* @see #showForm(HttpServletRequest, HttpServletResponse, BindException)
* @see #onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException)
* @see #onSubmit(Object, BindException)
* @see #onSubmit(Object)
* @see #doSubmitAction(Object)
*/
protected ModelAndView processFormSubmission(
HttpServletRequest request, HttpServletResponse response, Object command, BindException errors)
throws Exception {
if (errors.hasErrors()) {
if (logger.isDebugEnabled()) {
logger.debug("Data binding errors: " + errors.getErrorCount());
}
return showForm(request, response, errors);
}
else if (isFormChangeRequest(request, command)) {
logger.debug("Detected form change request -> routing request to onFormChange");
onFormChange(request, response, command, errors);
return showForm(request, response, errors);
}
else {
logger.debug("No errors -> processing submit");
return onSubmit(request, response, command, errors);
}
}
/**
* This implementation delegates to {@link #isFormChangeRequest(HttpServletRequest, Object)}:
* A form change request changes the appearance of the form and should not get
* validated but just show the new form.
* @see #isFormChangeRequest
*/
protected boolean suppressValidation(HttpServletRequest request, Object command) {
return isFormChangeRequest(request, command);
}
/**
* 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.
* <p>Gets called by {@link #suppressValidation} and {@link #processFormSubmission}.
* Consequently, this single method determines to suppress validation
* <i>and to show the form view in any case.
* <p>The default implementation delegates to
* {@link #isFormChangeRequest(javax.servlet.http.HttpServletRequest)}.
* @param request current HTTP request
* @param command form object with request parameters bound onto it
* @return whether the given request is a form change request
* @see #suppressValidation
* @see #processFormSubmission
*/
protected boolean isFormChangeRequest(HttpServletRequest request, Object command) {
return isFormChangeRequest(request);
}
/**
* Simpler <code>isFormChangeRequest variant, called by the full
* variant {@link #isFormChangeRequest(HttpServletRequest, Object)}.
* <p>The default implementation returns false. Allows subclasses to implement custom logic
* to modify the command object to directly modify data in the form.
* <p>The default implementation delegates to
* {@link #onFormChange(HttpServletRequest, HttpServletResponse, Object, BindException)}.
* @param request current servlet request
* @param response current servlet response
* @param command form object with request parameters bound onto it
* @param errors validation errors holder, allowing for additional
* custom validation
* @throws Exception in case of errors
* @see #isFormChangeRequest(HttpServletRequest)
* @see #onFormChange(HttpServletRequest, HttpServletResponse, Object)
*/
protected void onFormChange(
HttpServletRequest request, HttpServletResponse response, Object command, BindException errors)
throws Exception {
onFormChange(request, response, command);
}
/**
* Simpler <code>onFormChange variant, called by the full variant
* {@link #onFormChange(HttpServletRequest, HttpServletResponse, Object, BindException)}.
* <p>The default implementation is empty.
* @param request current servlet request
* @param response current servlet response
* @param command form object with request parameters bound onto it
* @throws Exception in case of errors
* @see #onFormChange(HttpServletRequest, HttpServletResponse, Object, BindException)
*/
protected void onFormChange(HttpServletRequest request, HttpServletResponse response, Object command)
throws Exception {
}
/**
* Submit callback with all parameters. Called in case of submit without errors
* reported by the registered validator, or on every submit if no validator.
* <p>The default implementation delegates to {@link #onSubmit(Object, BindException)}.
* For simply performing a submit action and rendering the specified success
* view, consider implementing {@link #doSubmitAction} rather than an
* <code>onSubmit variant.
* <p>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 <i>not implement multiple onSubmit
* methods: In that case, just this method will be called by the controller.
* <p>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.
* @param request current servlet request
* @param response current servlet response
* @param command form object with request parameters bound onto it
* @param errors Errors instance without errors (subclass can add errors if it wants to)
* @return the prepared model and view, or <code>null
* @throws Exception in case of errors
* @see #onSubmit(Object, BindException)
* @see #doSubmitAction
* @see #showForm
* @see org.springframework.validation.Errors
* @see org.springframework.validation.BindException#getModel
*/
protected ModelAndView onSubmit(
HttpServletRequest request, HttpServletResponse response, Object command, BindException errors)
throws Exception {
return onSubmit(command, errors);
}
/**
* Simpler <code>onSubmit variant.
* Called by the default implementation of the
* {@link #onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException)}
* variant with all parameters.
* <p>The default implementation calls {@link #onSubmit(Object)}, using the
* returned ModelAndView if actually implemented in a subclass. Else, the
* default behavior will apply: rendering the success view with the command
* and Errors instance as model.
* <p>Subclasses can override this to provide custom submission handling that
* does not need request and response.
* <p>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.
* @param command form object with request parameters bound onto it
* @param errors Errors instance without errors
* @return the prepared model and view
* @throws Exception in case of errors
* @see #onSubmit(HttpServletRequest, HttpServletResponse, Object, BindException)
* @see #onSubmit(Object)
* @see #setSuccessView
* @see org.springframework.validation.Errors
* @see org.springframework.validation.BindException#getModel
*/
protected ModelAndView onSubmit(Object command, BindException errors) throws Exception {
ModelAndView mv = onSubmit(command);
if (mv != null) {
// simplest onSubmit variant implemented in custom subclass
return mv;
}
else {
// default behavior: render success view
if (getSuccessView() == null) {
throw new ServletException("successView isn't set");
}
return new ModelAndView(getSuccessView(), errors.getModel());
}
}
/**
* Simplest <code>onSubmit variant. Called by the default implementation
* of the {@link #onSubmit(Object, BindException)} variant.
* <p>This implementation calls {@link #doSubmitAction(Object)} and returns
* <code>null as ModelAndView, making the calling onSubmit
* method perform its default rendering of the success view.
* <p>Subclasses can override this to provide custom submission handling
* that just depends on the command object. It's preferable to use either
* {@link #onSubmit(Object, BindException)} or {@link #doSubmitAction(Object)},
* 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.
* @param command form object with request parameters bound onto it
* @return the prepared model and view, or <code>null for default
* (that is, rendering the configured "successView")
* @throws Exception in case of errors
* @see #onSubmit(Object, BindException)
* @see #doSubmitAction
* @see #setSuccessView
*/
protected ModelAndView onSubmit(Object command) throws Exception {
doSubmitAction(command);
return null;
}
/**
* Template method for submit actions. Called by the default implementation
* of the simplest {@link #onSubmit(Object)} variant.
* <p>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.</b>
* You don't need to care about the success ModelAndView here.
* @param command form object with request parameters bound onto it
* @throws Exception in case of errors
* @see #onSubmit(Object)
* @see #setSuccessView
*/
protected void doSubmitAction(Object command) throws Exception {
}
}
Other Spring Framework examples (source code examples)
Here is a short list of links related to this Spring Framework SimpleFormController.java source code file:
The search page
Other Spring Framework source code examples at this package level
Click here to learn more about this project
