org.apache.struts.actions.EventDispatchAction Maven / Gradle / Ivy
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/*
* $Id: EventDispatchAction.java 384134 2006-03-08 06:43:55Z niallp $
*
* Copyright 2006 The Apache Software Foundation.
*
* 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.apache.struts.actions;
import java.util.StringTokenizer;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForward;
/**
* An Action that dispatches to to one of the public methods
* that are named in the parameter attribute of the corresponding
* ActionMapping and matches a submission parameter. This is useful for
* developers who prefer to use many submit buttons, images, or submit links
* on a single form and whose related actions exist in a single Action class.
*
* The method(s) must have the same signature (other than method name) of the
* standard Action.execute method.
*
* To configure the use of this action in your
* struts-config.xml file, create an entry like this:
*
*
* <action path="/saveSubscription"
* type="org.example.SubscriptionAction"
* name="subscriptionForm"
* scope="request"
* input="/subscription.jsp"
* parameter="save,back,recalc=recalculate,default=save"/>
*
*
* where parameter contains three possible methods and one
* default method if nothing matches (such as the user pressing the enter key).
*
* For utility purposes, you can use the key=value notation to
* alias methods so that they are exposed as different form element names, in the
* event of a naming conflict or otherwise. In this example, the recalc
* button (via a request parameter) will invoke the recalculate
* method. The security-minded person may find this feature valuable to
* obfuscate and not expose the methods.
*
* The default key is purely optional. If this is not specified
* and no parameters match the list of method keys, null is
* returned which means the unspecified method will be invoked.
*
* The order of the parameters are guaranteed to be iterated in the order
* specified. If multiple buttons were accidently submitted, the first match in
* the list will be dispatched.
*
* @since Struts 1.2.9
*/
public class EventDispatchAction extends DispatchAction {
/**
* Commons Logging instance.
*/
private static final Log LOG = LogFactory.getLog(EventDispatchAction.class);
/**
* The method key, if present, to use if other specified method keys
* do not match a request parameter.
*/
private static final String DEFAULT_METHOD_KEY = "default";
// --------------------------------------------------------- Protected Methods
/**
* Method which is dispatched to when there is no value for specified
* request parameter included in the request. Subclasses of
* DispatchAction should override this method if they wish to
* provide default behavior different than throwing a ServletException.
*
* @param mapping The ActionMapping used to select this instance
* @param form The optional ActionForm bean for this request (if any)
* @param request The non-HTTP request we are processing
* @param response The non-HTTP response we are creating
* @return The forward to which control should be transferred, or
* null if the response has been completed.
* @throws Exception if the application business logic throws an
* exception.
*/
protected ActionForward unspecified(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
String message =
messages.getMessage("event.parameter", mapping.getPath(),
mapping.getParameter());
LOG.error(message + " " + mapping.getParameter());
throw new ServletException(message);
}
/**
* Returns the method name, given a parameter's value.
*
* @param mapping The ActionMapping used to select this instance
* @param form The optional ActionForm bean for this request (if
* any)
* @param request The HTTP request we are processing
* @param response The HTTP response we are creating
* @param parameter The ActionMapping parameter's name
* @return The method's name.
* @throws Exception if an error occurs.
*/
protected String getMethodName(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response,
String parameter) throws Exception {
StringTokenizer st = new StringTokenizer(parameter, ",");
String defaultMethodName = null;
while (st.hasMoreTokens()) {
String methodKey = st.nextToken().trim();
String methodName = methodKey;
// The key can either be a direct method name or an alias
// to a method as indicated by a "key=value" signature
int equals = methodKey.indexOf('=');
if (equals > -1) {
methodName = methodKey.substring(equals + 1).trim();
methodKey = methodKey.substring(0, equals).trim();
}
// Set the default if it passes by
if (methodKey.equals(DEFAULT_METHOD_KEY)) {
defaultMethodName = methodName;
}
// If the method key exists as a standalone parameter or with
// the image suffixes (.x/.y), the method name has been found.
if ((request.getParameter(methodKey) != null)
|| (request.getParameter(methodKey + ".x") != null)) {
return methodName;
}
}
return defaultMethodName;
}
}