abstractwizardformcontroller.java

spring的源代码

			request.getSession().setAttribute(getPageSessionAttributeName(), new Integer(page));
			// set page request attribute for evaluation by views
			Map controlModel = new HashMap();
			if (this.pageAttribute != null) {
				controlModel.put(this.pageAttribute, new Integer(page));
			}
			return showForm(request, errors, this.pages[page], controlModel);
		}
		else {
			throw new ServletException("Invalid page number: " + page);
		}
	}

	/**
	 * Return the initial page of the wizard, i.e. the page shown at wizard startup.
	 * Default implementation delegates to getInitialPage(HttpServletRequest).
	 * @param request current HTTP request
	 * @param command the command object as returned by formBackingObject
	 * @return the initial page number
	 * @see #getInitialPage(HttpServletRequest)
	 * @see #formBackingObject
	 */
	protected int getInitialPage(HttpServletRequest request, Object command) {
		return getInitialPage(request);
	}

	/**
	 * Return the initial page of the wizard, i.e. the page shown at wizard startup.
	 * Default implementation returns 0 for first page.
	 * @param request current HTTP request
	 * @return the initial page number
	 */
	protected int getInitialPage(HttpServletRequest request) {
		return 0;
	}

	/**
	 * Return the name of the session attribute that holds
	 * the page object for this controller.
	 * @return the name of the page session attribute
	 */
	protected final String getPageSessionAttributeName() {
		return getClass() + ".page." + getCommandName();
	}

	/**
	 * 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
	 * @param response current HTTP response
	 * @return a prepared view, or null if handled directly
	 * @throws Exception in case of errors
	 * @see #showNewForm
	 * @see #setBindOnNewForm
	 */
	protected ModelAndView handleInvalidSubmit(HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		return showNewForm(request, response);
	}

	/**
	 * Apply wizard workflow: finish, cancel, page change.
	 */
	protected final ModelAndView processFormSubmission(HttpServletRequest request, HttpServletResponse response,
	                                                   Object command, BindException errors) throws Exception {
		int currentPage = getCurrentPage(request);
		request.getSession().removeAttribute(getPageSessionAttributeName());

		// cancel?
		if (isCancel(request)) {
			logger.debug("Cancelling wizard for form bean '" + getCommandName() + "'");
			return processCancel(request, response, command, errors);
		}

		// finish?
		if (isFinish(request)) {
			logger.debug("Finishing wizard for form bean '" + getCommandName() + "'");
			return validatePagesAndFinish(request, response, command, errors);
		}

		// normal submit: validate current page and show specified target page
		logger.debug("Validating wizard page " + currentPage + " for form bean '" + getCommandName() + "'");
		validatePage(command, errors, currentPage);

		int targetPage = getTargetPage(request, command, errors, currentPage);
		logger.debug("Target page " + targetPage + " requested");
		if (targetPage != currentPage) {
			if (!errors.hasErrors() || (this.allowDirtyBack && targetPage < currentPage) ||
					(this.allowDirtyForward && targetPage > currentPage)) {
				// allowed to go to target page
				return showPage(request, errors, targetPage);
			}		
		}
		
		// show current page again
		return showPage(request, errors, currentPage);
	}

	/**
	 * Return the current page number. Used by processFormSubmission.
	 * Can also be called by page-specific onBindAndValidate implementations,
	 * as methods like validatePage explicitly feature a page parameter.
	 * <p>The default implementation checks the page session attribute.
	 * Subclasses can override this for customized target page determination.
	 * @throws IllegalStateException if the page attribute isn't in the session
	 * anymore, i.e. when called after processFormSubmission.
	 * @see #getPageSessionAttributeName
	 */
	protected int getCurrentPage(HttpServletRequest request) throws IllegalStateException {
		Integer pageAttr = (Integer) request.getSession().getAttribute(getPageSessionAttributeName());
		if (pageAttr == null) {
			throw new IllegalStateException("Page attribute isn't in session anymore - called after processFormSubmission?");
		}
		return pageAttr.intValue();
	}

	/**
	 * Return if finish action is specified in the request.
	 * @param request current HTTP request
	 */
	protected boolean isFinish(HttpServletRequest request) {
		return WebUtils.hasSubmitParameter(request, PARAM_FINISH);
	}

	/**
	 * Return if cancel action is specified in the request.
	 * @param request current HTTP request
	 */
	protected boolean isCancel(HttpServletRequest request) {
		return WebUtils.hasSubmitParameter(request, PARAM_CANCEL);
	}

	/**
	 * Return the target page specified in the request.
	 * <p>Default implementation delegates to getTargetPage(HttpServletRequest, int).
	 * Subclasses can override this for customized target page determination.
	 * @param request current HTTP request
	 * @param command form object with request parameters bound onto it
	 * @param errors 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
	 * @see #getTargetPage(HttpServletRequest, int)
	 */
	protected int getTargetPage(HttpServletRequest request, Object command, Errors errors, int currentPage) {
		return getTargetPage(request, currentPage);
	}

	/**
	 * Return the target page specified in the request.
	 * <p>Default implementation examines "_target" parameter (e.g. "_target1").
	 * Subclasses can override this for customized target page determination.
	 * @param request current HTTP request
	 * @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
	 * @see #PARAM_TARGET
	 */
	protected int getTargetPage(HttpServletRequest request, 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 respective view page.
	 */
	private ModelAndView validatePagesAndFinish(HttpServletRequest request, HttpServletResponse response,
	                                            Object command, BindException errors) throws Exception {
		for (int page = 0; page < pages.length; page++) {
			validatePage(command, errors, page);
			// in case of field errors on a page -> show the page
			if (errors.getErrorCount() - errors.getGlobalErrorCount() > 0) {
				return showPage(request, errors, page);
			}
		}
		// no field errors -> maybe global errors, or none at all
		return processFinish(request, response, command, errors);
	}

	/**
	 * Template method for custom validation logic for individual pages.
	 * Implementations will typically call fine-granular validateXXX methods of this
	 * instance's validator, combining them to validation of the respective pages.
	 * The validator's default validate method will not be called by a wizard controller!
	 * @param command form object with the current wizard state
	 * @param errors validation errors holder
	 * @param page number of page to show
	 */
	protected abstract void validatePage(Object command, Errors errors, int page);

	/**
	 * Template method for processing the final action of this wizard.
	 * <p>Can call errors.getModel() to populate the ModelAndView model with the command
	 * and the Errors instance, under the specified bean name.
	 * @param request current HTTP request
	 * @param response current HTTP response
	 * @param command form object with the current wizard state
	 * @param errors validation errors holder
	 * @return the finish view
	 * @throws Exception in case of invalid state or arguments
	 * @see org.springframework.validation.Errors
	 */
	protected abstract ModelAndView processFinish(HttpServletRequest request, HttpServletResponse response,
	                                              Object command, BindException errors) throws Exception;

	/**
	 * Template method for processing the cancel action of this wizard.
	 * <p>Can call errors.getModel() to populate the ModelAndView model with the command
	 * and the Errors instance, under the specified bean name.
	 * @param request current HTTP request
	 * @param response current HTTP response
	 * @param command form object with the current wizard state
	 * @param errors Errors instance containing errors
	 * @return the finish view
	 * @throws Exception in case of invalid state or arguments
	 * @see org.springframework.validation.Errors
	 */
	protected abstract ModelAndView processCancel(HttpServletRequest request, HttpServletResponse response,
	                                              Object command, BindException errors) throws Exception;

}