org.springframework.web.servlet.mvc.CancellableFormController Maven / Gradle / Ivy
/*
* 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;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.validation.BindException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.util.WebUtils;
/**
* 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):
*
* - Call to {@link #processFormSubmission processFormSubmission} which calls
* {@link #isCancelRequest} to see if the incoming request is to cancel the
* current form entry. By default, {@link #isCancelRequest} returns
true
* if the configured cancelParamKey exists in the request.
* This behavior can be overridden in subclasses.
* - If {@link #isCancelRequest} returns
false, then the controller
* will delegate all processing back to {@link SimpleFormController SimpleFormController},
* otherwise it will call the {@link #onCancel} version with all parameters.
* By default, that method will delegate to the {@link #onCancel} version with just
* the command object, which will in turn simply return the configured
* cancelView. This behavior can be overridden in subclasses.
*
*
*
* @author Rob Harrop
* @author Juergen Hoeller
* @author Erwin Bolwidt
* @since 1.2.3
* @see #setCancelParamKey
* @see #setCancelView
* @see #isCancelRequest(javax.servlet.http.HttpServletRequest)
* @see #onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, Object)
*/
public class CancellableFormController extends SimpleFormController {
/**
* Default parameter triggering the cancel action.
* Can be called even with validation errors on the form.
*/
private static final String PARAM_CANCEL = "_cancel";
private String cancelParamKey = PARAM_CANCEL;
private String cancelView;
/**
* 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").
*/
public final void setCancelParamKey(String cancelParamKey) {
this.cancelParamKey = cancelParamKey;
}
/**
* Return the key of the request parameter used to identify a cancel request.
*/
public final String getCancelParamKey() {
return cancelParamKey;
}
/**
* Sets the name of the cancel view.
*/
public final void setCancelView(String cancelView) {
this.cancelView = cancelView;
}
/**
* Gets the name of the cancel view.
*/
public final String getCancelView() {
return cancelView;
}
/**
* Consider an explicit cancel request as a form submission too.
* @see #isCancelRequest(javax.servlet.http.HttpServletRequest)
*/
protected boolean isFormSubmission(HttpServletRequest request) {
return super.isFormSubmission(request) || isCancelRequest(request);
}
/**
* This implementation first checks to see if the incoming is a cancel request,
* through a call to {@link #isCancelRequest}. If so, control is passed to
* {@link #onCancel}; otherwise, control is passed up to
* {@link SimpleFormController#processFormSubmission}.
* @see #isCancelRequest
* @see #onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, Object)
* @see SimpleFormController#processFormSubmission
*/
protected ModelAndView processFormSubmission(
HttpServletRequest request, HttpServletResponse response, Object command, BindException errors)
throws Exception {
if (isCancelRequest(request)) {
return onCancel(request, response, command);
}
else {
return super.processFormSubmission(request, response, command, errors);
}
}
/**
* 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").
* @param request current HTTP request
* @see #setCancelParamKey
* @see #PARAM_CANCEL
*/
protected boolean isCancelRequest(HttpServletRequest request) {
return WebUtils.hasSubmitParameter(request, getCancelParamKey());
}
/**
* Callback method for handling a cancel request. Called if {@link #isCancelRequest}
* 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 {@link ModelAndView 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 {@link #setCancelView(String)} rather than
* overriding an onCancel method.
* @param request current servlet request
* @param response current servlet response
* @param command form object with request parameters bound onto it
* @return the prepared model and view, or null
* @throws Exception in case of errors
* @see #isCancelRequest(javax.servlet.http.HttpServletRequest)
* @see #onCancel(Object)
* @see #setCancelView
*/
protected ModelAndView onCancel(HttpServletRequest request, HttpServletResponse response, Object command)
throws Exception {
return onCancel(command);
}
/**
* 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 {@link ModelAndView 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 {@link #setCancelView(String)} rather than
* overriding an onCancel method.
* @param command form object with request parameters bound onto it
* @return the prepared model and view, or null
* @throws Exception in case of errors
* @see #onCancel(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, Object)
* @see #setCancelView
*/
protected ModelAndView onCancel(Object command) throws Exception {
return new ModelAndView(getCancelView());
}
}