/*
* Copyright 2002-2005 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.form;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import org.springframework.validation.BindingResult;
import org.springframework.validation.Errors;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.util.WebUtils;
/**
* Form controller for typical wizard-style workflows.
*
* <p>In contrast to classic forms, wizards have more than one form view page.
* Therefore, there are various actions instead of one single submit action:
* <ul>
* <li>finish: trying to leave the wizard successfully, i.e. performing its
* final action, and thus needing a valid state;
* <li>cancel: leaving the wizard without performing its final action, and
* thus without regard to the validity of its current state;
* <li>page change: showing another wizard page, e.g. the next or previous
* one, with regard to "dirty back" and "dirty forward".
* </ul>
*
* <p>Finish and cancel actions can be triggered by request parameters, named
* PARAM_FINISH ("_finish") and PARAM_CANCEL ("_cancel"), ignoring parameter
* values to allow for HTML buttons. The target page for page changes can be
* specified by PARAM_TARGET, appending the page number to the parameter name
* (e.g. "_target1"). The action parameters are recognized when triggered by
* image buttons too (via "_finish.x", "_abort.x", or "_target1.x").
*
* <p>The current page number will be stored in the session. It can also be
* specified as request parameter PARAM_PAGE, to properly handle usage of
* the back button in a browser: In this case, a submission always contains
* the correct page number, even if the user submitted from an old view.
*
* <p>The page can only be changed if it validates correctly, except if a
* "dirty back" or "dirty forward" is allowed. At finish, all pages get
* validated again to guarantee a consistent state.
*
* <p>Note that a validator's default validate method is not executed when using
* this class! Rather, the <code>validatePage</code> implementation should call
* special <code>validateXXX</code> methods that the validator needs to provide,
* validating certain pieces of the object. These can be combined to validate
* the elements of individual pages.
*
* <p>Note: Page numbering starts with 0, to be able to pass an array
* consisting of the corresponding view names to the "pages" bean property.
*
* @author Juergen Hoeller
* @since 25.04.2003
* @see #setPages
* @see #validatePage
* @see #processFinish
* @see #processCancel
*/
public abstract class AbstractWizardFormController extends AbstractFormController {
/**
* Parameter triggering the finish action.
* Can be called from any wizard page!
*/
public static final String PARAM_FINISH = "_finish";
/**
* Parameter triggering the cancel action.
* Can be called from any wizard page!
*/
public static final String PARAM_CANCEL = "_cancel";
/**
* Parameter specifying the target page,
* appending the page number to the name.
*/
public static final String PARAM_TARGET = "_target";
/**
* Parameter specifying the current page as value. Not necessary on
* form pages, but allows to properly handle usage of the back button.
* @see #setPageAttribute
*/
public static final String PARAM_PAGE = "_page";
private String[] pages;
private String pageAttribute;
private boolean allowDirtyBack = true;
private boolean allowDirtyForward = false;
/**
* Create a new AbstractWizardFormController.
* <p>"sessionForm" is automatically turned on, "validateOnBinding"
* turned off, and "cacheSeconds" set to 0 by the base class
* (-> no caching for all form controllers).
*/
public AbstractWizardFormController() {
// AbstractFormController sets default cache seconds to 0.
super();
// Always needs session to keep data from all pages.
setSessionForm(true);
// Never validate everything on binding ->
// wizards validate individual pages.
setValidateOnBinding(false);
}
/**
* Set the wizard pages, i.e. the view names for the pages.
* The array index is interpreted as page number.
* @param pages view names for the pages
*/
public final void setPages(String[] pages) {
if (pages == null || pages.length == 0) {
throw new IllegalArgumentException("No wizard pages defined");
}
this.pages = pages;
}
/**
* Return the wizard pages, i.e. the view names for the pages.
* The array index corresponds to the page number.
* <p>Note that a concrete wizard form controller might override
* <code>getViewName(HttpServletRequest, Object, int)</code> to
* determine the view name for each page dynamically.
* @see #getViewName(javax.servlet.http.HttpServletRequest, Object, int)
*/
public final String[] getPages() {
return pages;
}
/**
* Return the number of wizard pages.
* Useful to check whether the last page has been reached.
* <p>Note that a concrete wizard form controller might override
* <code>getPageCount(HttpServletRequest, Object)</code> to determine
* the page count dynamically. The default implementation of that extended
* <code>getPageCount</code> variant returns the static page count as
* determined by this <code>getPageCount()</code> method.
* @see #getPageCount(javax.servlet.http.HttpServletRequest, Object)
*/
protected final int getPageCount() {
return this.pages.length;
}
/**
* Set the name of the page attribute in the model, containing
* an Integer with the current page number.
* <p>This will be necessary for single views rendering multiple view pages.
* It also allows for specifying the optional "_page" parameter.
* @param pageAttribute name of the page attribute
* @see #PARAM_PAGE
*/
public final void setPageAttribute(String pageAttribute) {
this.pageAttribute = pageAttribute;
}
/**
* Return the name of the page attribute in the model.
*/
public final String getPageAttribute() {
return pageAttribute;
}
/**
* Set if "dirty back" is allowed, i.e. if moving to a former wizard
* page is allowed in case of validation errors for the current page.
* @param allowDirtyBack if "dirty back" is allowed
*/
public final void setAllowDirtyBack(boolean allowDirtyBack) {
this.allowDirtyBack = allowDirtyBack;
}
/**
* Return whether "dirty back" is allowed.
*/
public final boolean isAllowDirtyBack() {
return allowDirtyBack;
}
/**
* Set if "dirty forward" is allowed, i.e. if moving to a later wizard
* page is allowed in case of validation errors for the current page.
* @param allowDirtyForward if "dirty forward" is allowed
*/
public final void setAllowDirtyForward(boolean allowDirtyForward) {
this.allowDirtyForward = allowDirtyForward;
}
/**
* Return whether "dirty forward" is allowed.
*/
public final boolean isAllowDirtyForward() {
return allowDirtyForward;
}
/**
* Calls page-specific onBindAndValidate method.
*/
protected final void onBindAndValidate(HttpServletRequest request, BindingResult bindingResult) throws Exception {
onBindAndValidate(request, bindingResult, getCurrentPage(request));
}
/**
* Callback for custom post-processing in terms of binding and validation.
* Called on each submit, after standard binding but before page-specific
* validation of this wizard form controller.
* <p>Note: AbstractWizardFormController does not perform standand
* validation on binding but rather applies page-specific validation
* on processing the form submission.
* @param request current HTTP request
* @param bindingResult Errors instance for additional custom validation
* @param page current wizard page
* @throws Exception in case of invalid state or arguments
* @see #bindAndValidate
* @see #processFormSubmission
* @see org.springframework.validation.Errors
*/
protected void onBindAndValidate(HttpServletRequest request, BindingResult bindingResult, int page)
throws Exception {
}
/**
* Consider an explicit finish or cancel request as a form submission too.
* @see #isFinishRequest(javax.servlet.http.HttpServletRequest)
* @see #isCancelRequest(javax.servlet.http.HttpServletRequest)
*/
protected boolean isFormSubmission(HttpServletRequest request) {
return super.isFormSubmission(request) || isFinishRequest(request) || isCancelRequest(request);
}
/**
* Calls page-specific referenceData method.
*/
protected final Map referenceData(HttpServletRequest request, BindingResult bindingResult) throws Exception {
return referenceData(request, bindingResult, getCurrentPage(request));
}
/**
* Create a reference data map for the given request, consisting of
* bean name/bean instance pairs as expected by ModelAndView.
* <p>Default implementation delegates to referenceData(HttpServletRequest, int).
* Subclasses can override this to set reference data used in the view.
* @param request current HTTP request
* @param bindingResult validation errors holder
* @param page current wizard page
* @return a Map with reference data entries, or <code>null</code> if none
* @throws Exception in case of invalid state or arguments
* @see org.springframework.web.servlet.ModelAndView
*/
protected Map referenceData(HttpServletRequest request, BindingResult bindingResult, int page) throws Exception {
return null;
}
/**
* Show first page as form view.
*/
protected final ModelAndView showForm(HttpServletRequest request, BindingResult bindingResult) throws Exception {
return showPage(request, bindingResult, getInitialPage(request, bindingResult));
}
/**
* Prepare the form model and view, including reference and error data,
* for the given page. Can be used in <code>processFinish</code> implementations,
* to show the corresponding page in case of validation errors.
* @param request current HTTP request
* @param errors validation errors holder
* @param page number of page to show
* @return the prepared form view
* @throws Exception in case of invalid state or arguments
*/
protected final ModelAndView showPage(HttpServletRequest request, BindingResult errors, int page)
throws Exception {
if (page >= 0 && page < getPageCount(request, errors.getTarget())) {
if (logger.isDebugEnabled()) {
logger.debug("Showing wizard page " + page + " for form bean '" + getFormObjectName() + "'");
}
// Set page session attribute, expose overriding request attribute.
Integer pageInteger = new Integer(page);
String pageAttrName = getPageSessionAttributeName(request);
if (isSessionForm()) {
if (logger.isDebugEnabled()) {
logger.debug("Setting page session attribute [" + pageAttrName + "] to: " + pageInteger);
}
request.getSession().setAttribute(pageAttrName, pageInteger);
}
request.setAttribute(pageAttrName, pageInteger);
// Set page request attribute for evaluation by views.
Map controlModel = new HashMap();
if (this.pageAttribute != null) {
controlModel.put(this.pageAttribute, new Integer(page));
}
String viewName = getViewName(request, errors.getTarget(), page);
return showForm(request, errors, viewName, controlModel);
}
else {
throw new ServletException("Invalid wizard page number: " + page);
}
}
/**
* Return the page count for this wizard form controller.
* Default implementation delegates to <code>getPageCount()</code>.
* <p>Can be overridden to dynamically adapt the page count.
* @param request current HTTP request
* @param command the command object as returned by formBackingObject
* @return the current page count
* @see #getPageCount
*/
protected int getPageCount(HttpServletRequest request, Object command) {
return getPageCount();
}
/**
* Return the name of the view for the specified page of this wizard form controller.
* Default implementation takes the view name from the <code>getPages()</code> array.
* <p>Can be overridden to dynamically switch the page view or to return view names
* for dynamically defined pages.
* @param request current HTTP request
* @param command the command object as returned by formBackingObject
* @return the current page count
* @see #getPageCount
*/
protected String getViewName(HttpServletRequest request, Object command, int page) {
return getPages()[page];
}
/**
* Return the initial page of the wizard, i.e. the page shown at wizard startup.
* Default implementation delegates to <code>getInitialPage(HttpServletRequest)</code>.
* @param request current HTTP request
* @param bindingResult validation errors holder
* @return the initial page number
* @see #formBackingObject
*/
protected int getInitialPage(HttpServletRequest request, BindingResult bindingResult) {
return 0;
}
/**
* Return the name of the HttpSession attribute that holds the page object
* for this wizard form controller.
* <p>Default implementation delegates to the <code>getPageSessionAttributeName</code>
* version without arguments.
* @param request current HTTP request
* @return the name of the form session attribute
* @see #getPageSessionAttributeName
* @see #getFormSessionAttributeName(javax.servlet.http.HttpServletRequest)
* @see javax.servlet.http.HttpSession#getAttribute
*/
protected String getPageSessionAttributeName(HttpServletRequest request) {
return getClass().getName() + ".PAGE." + getFormObjectName();
}
/**
* Handle an invalid submit request, e.g. when in session form mode but no form object
* was found in the session (like in case of an invalid resubmit by the browser).
* <p>Default implementation for wizard form controllers simply shows the initial page
* of a new wizard form. If you want to show some "invalid submit" message, you need
* to override this method.
* @param request current HTTP request
* @return a prepared view, or <code>null</code> if handled directly
* @throws Exception in case of errors
* @see #showNewForm
* @see #setBindOnNewForm
*/
protected ModelAndView handleInvalidSubmit(HttpServletRequest request) throws Exception {
return showNewForm(request);
}
/**
* Apply wizard workflow: finish, cancel, page change.
*/
protected final ModelAndView processFormSubmission(HttpServletRequest request, BindingResult bindingResult)
throws Exception {
int currentPage = getCurrentPage(request);
// Remove page session attribute, provide copy as request attribute.
String pageAttrName = getPageSessionAttributeName(request);
if (isSessionForm()) {
if (logger.isDebugEnabled()) {
logger.debug("Removing page session attribute [" + pageAttrName + "]");
}
request.getSession().removeAttribute(pageAttrName);
}
request.setAttribute(pageAttrName, new Integer(currentPage));
// cancel?
if (isCancelRequest(request)) {
if (logger.isDebugEnabled()) {
logger.debug("Cancelling wizard for form bean '" + getFormObjectName() + "'");
}
return processCancel(request, bindingResult);
}
// finish?
if (isFinishRequest(request)) {
if (logger.isDebugEnabled()) {
logger.debug("Finishing wizard for form bean '" + getFormObjectName() + "'");
}
return validatePagesAndFinish(request, bindingResult, currentPage);
}
// Normal submit: validate current page and show specified target page.
if (!suppressValidation(request)) {
if (logger.isDebugEnabled()) {
logger.debug("Validating wizard page " + currentPage + " for form bean '" + getFormObjectName() + "'");
}
validatePage(bindingResult.getTarget(), bindingResult, currentPage, false);
}
// Give subclasses a change to perform custom post-procession
// of the current page and its command object.
postProcessPage(request, bindingResult, currentPage);
int targetPage = getTargetPage(request, bindingResult, currentPage);
if (logger.isDebugEnabled()) {
logger.debug("Target page " + targetPage + " requested");
}
if (targetPage != currentPage) {
if (!bindingResult.hasErrors() || (this.allowDirtyBack && targetPage < currentPage) ||
(this.allowDirtyForward && targetPage > currentPage)) {
// Allowed to go to target page.
return showPage(request, bindingResult, targetPage);
}
}
// Show current page again.
return showPage(request, bindingResult, currentPage);
}
/**
* Return the current page number. Used by processFormSubmission.
* <p>The default implementation checks the page session attribute.
* Subclasses can override this for customized page determination.
* @see #processFormSubmission
* @see #getPageSessionAttributeName
*/
protected int getCurrentPage(HttpServletRequest request) {
// Check for overriding attribute in request.
String pageAttrName = getPageSessionAttributeName(request);
Integer pageAttr = (Integer) request.getAttribute(pageAttrName);
if (pageAttr != null) {
return pageAttr.intValue();
}
// Check for explicit request parameter.
String pageParam = request.getParameter(PARAM_PAGE);
if (pageParam != null) {
return Integer.parseInt(pageParam);
}
// Check for original attribute in session.
if (isSessionForm()) {
pageAttr = (Integer) request.getSession().getAttribute(pageAttrName);
if (pageAttr != null) {
return pageAttr.intValue();
}
}
throw new IllegalStateException(
"Page attribute [" + pageAttrName + "] neither found in session nor in request");
}
/**
* Determine whether the incoming request is a request to finish the
* processing of the current form.
* <p>By default, this method returns <code>true</code> if a parameter
* matching the "_finish" key is present in the request, otherwise it
* returns <code>false</code>. Subclasses may override this method
* to provide custom logic to detect a finish request.
* <p>The parameter is recognized both when sent as a plain parameter
* ("_finish") or when triggered by an image button ("_finish.x").
* @param request current HTTP request
* @see #PARAM_FINISH
*/
protected boolean isFinishRequest(HttpServletRequest request) {
return WebUtils.hasSubmitParameter(request, PARAM_FINISH);
}
/**
* Determine whether the incoming request is a request to cancel the
* processing of the current form.
* <p>By default, this method returns <code>true</code> if a parameter
* matching the "_cancel" key is present in the request, otherwise it
* returns <code>false</code>. Subclasses may override this method
* to provide custom logic to detect a cancel request.
* <p>The parameter is recognized both when sent as a plain parameter
* ("_cancel") or when triggered by an image button ("_cancel.x").
* @param request current HTTP request
* @see #PARAM_CANCEL
*/
protected boolean isCancelRequest(HttpServletRequest request) {
return WebUtils.hasSubmitParameter(request, PARAM_CANCEL);
}
/**
* Return the target page specified in the request.
* <p>Default implementation delegates to
* <code>getTargetPage(HttpServletRequest, int)</code>.
* Subclasses can override this for customized target page determination.
* @param request current HTTP request
* @param bindingResult validation errors holder
* @param currentPage the current page, to be returned as fallback
* if no target page specified
* @return the page specified in the request, or current page if not found
*/
protected int getTargetPage(HttpServletRequest request, BindingResult bindingResult, int currentPage) {
Enumeration paramNames = request.getParameterNames();
while (paramNames.hasMoreElements()) {
String paramName = (String) paramNames.nextElement();
if (paramName.startsWith(PARAM_TARGET)) {
for (int i = 0; i < WebUtils.SUBMIT_IMAGE_SUFFIXES.length; i++) {
String suffix = WebUtils.SUBMIT_IMAGE_SUFFIXES[i];
if (paramName.endsWith(suffix)) {
paramName = paramName.substring(0, paramName.length() - suffix.length());
}
}
return Integer.parseInt(paramName.substring(PARAM_TARGET.length()));
}
}
return currentPage;
}
/**
* Validate all pages and process finish.
* If there are page validation errors, show the corresponding view page.
*/
private ModelAndView validatePagesAndFinish(
HttpServletRequest request, BindingResult bindingResult, int currentPage) throws Exception {
// In case of binding errors -> show current page.
if (bindingResult.hasErrors()) {
return showPage(request, bindingResult, currentPage);
}
if (!suppressValidation(request)) {
// In case of remaining errors on a page -> show the page.
for (int page = 0; page < getPageCount(request, bindingResult); page++) {
validatePage(bindingResult, bindingResult, page, true);
if (bindingResult.hasErrors()) {
return showPage(request, bindingResult, page);
}
}
}
// No remaining errors -> proceed with finish.
return processFinish(request, bindingResult);
}
/**
* Template method for custom validation logic for individual pages.
* Default implementation calls <code>validatePage(command, errors, page)</code>.
* <p>Implementations will typically call fine-granular <code>validateXXX</code>
* methods of this instance's Validator, combining them to validation of the
* corresponding pages. The Validator's default <code>validate</code> method
* will not be called by a wizard form controller!
* @param command form object with the current wizard state
* @param errors validation errors holder
* @param page number of page to validate
* @param finish whether this method is called during final revalidation on finish
* (else, it is called for validating the current page)
* @see #validatePage(Object, org.springframework.validation.Errors, int)
* @see org.springframework.validation.Validator#validate
*/
protected void validatePage(Object command, Errors errors, int page, boolean finish) {
validatePage(command, errors, page);
}
/**
* Template method for custom validation logic for individual pages.
* Default implementation is empty.
* <p>Implementations will typically call fine-granular validateXXX methods of this
* instance's validator, combining them to validation of the corresponding pages.
* The validator's default <code>validate</code> method will not be called by a
* wizard form controller!
* @param command form object with the current wizard state
* @param errors validation errors holder
* @param page number of page to validate
* @see org.springframework.validation.Validator#validate
*/
protected void validatePage(Object command, Errors errors, int page) {
}
/**
* Post-process the given page after binding and validation, potentially
* updating its command object. The passed-in request might contain special
* parameters sent by the page.
* <p>Only invoked when displaying another page or the same page again,
* not when finishing or cancelling.
* @param request current HTTP request
* @param bindingResult validation errors holder
* @param page number of page to post-process
* @throws Exception in case of invalid state or arguments
*/
protected void postProcessPage(HttpServletRequest request, BindingResult bindingResult, int page)
throws Exception {
}
/**
* Template method for processing the final action of this wizard.
* <p>Call <code>errors.getModel()</code> to populate the ModelAndView model
* with the command and the Errors instance, under the specified command name,
* as expected by the "spring:bind" tag.
* <p>You can call the <code>showPage</code> method to return back to the wizard,
* in case of last-minute validation errors having been found that you would
* like to present to the user within the original wizard form.
* @param request current HTTP request
* @param bindingResult validation errors holder
* @return the finish view
* @throws Exception in case of invalid state or arguments
* @see org.springframework.validation.Errors
* @see org.springframework.validation.BindException#getModel
* @see #showPage(javax.servlet.http.HttpServletRequest, org.springframework.validation.BindingResult, int)
*/
protected abstract ModelAndView processFinish(HttpServletRequest request, BindingResult bindingResult)
throws Exception;
/**
* Template method for processing the cancel action of this wizard.
* <p>Default implementation throws a ServletException, saying that a cancel
* operation is not supported by this controller. Thus, you do not need to
* implement this template method if you do not support a cancel operation.
* <p>Call <code>errors.getModel()</code> 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 HTTP request
* @param bindingResult Errors instance containing errors
* @return the cancellation view
* @throws Exception in case of invalid state or arguments
* @see org.springframework.validation.Errors
* @see org.springframework.validation.BindException#getModel
*/
protected ModelAndView processCancel(HttpServletRequest request, BindingResult bindingResult) throws Exception {
throw new ServletException(
"Wizard form controller class [" + getClass().getName() + "] does not support a cancel operation");
}
}