craigmcc 01/03/29 10:40:31
Added: src/share/org/apache/struts/actions DispatchAction.java
Removed: src/share/org/apache/struts/action DispatchAction.java
Log:
Move DispatchAction to the "actions" directory with all the other standard
actions provided by Struts.
Revision Changes Path
1.1
jakarta-struts/src/share/org/apache/struts/actions/DispatchAction.java
Index: DispatchAction.java
===================================================================
/*
* $Header:
/home/cvs/jakarta-struts/src/share/org/apache/struts/actions/DispatchAction.java,v 1.1
2001/03/29 18:40:30 craigmcc Exp $
* $Revision: 1.1 $
* $Date: 2001/03/29 18:40:30 $
*
* ====================================================================
*
* The Apache Software License, Version 1.1
*
* Copyright (c) 1999-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Struts", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [EMAIL PROTECTED]
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.struts.actions;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.util.MessageResources;
/**
* <p>An abstract <strong>Action</strong> that dispatches to a public
* method that is named by the request parameter whose name is specified
* by the <code>parameter</code> property of the corresponding
* ActionMapping. This Action is useful for developers who prefer to
* combine many similar actions into a single Action class, in order to
* simplify their application design.</p>
*
* <p>To configure the use of this action in your
* <code>struts-config.xml</code> file, create an entry like this:</p>
*
* <code>
* <action path="/saveSubscription"
* type="org.apache.struts.actions.DispatchAction"
* name="subscriptionForm"
* scope="request"
* input="/subscription.jsp"
* parameter="method"/>
* </code>
*
* <p>which will use the value of the request parameter named "method"
* to pick the appropriate "perform" method, which must have the same
* signature (other than method name) of the standard Action.perform()
* method. For example, you might have the following three methods in the
* same action:</p>
* <ul>
* <li>public ActionForward delete(ActionMapping mapping, ActionForm form,
* HttpServletRequest request, HttpServletResponse response)
* throws IOException, ServletException</li>
* <li>public ActionForward insert(ActionMapping mapping, ActionForm form,
* HttpServletRequest request, HttpServletResponse response)
* throws IOException, ServletException</li>
* <li>public ActionForward update(ActionMapping mapping, ActionForm form,
* HttpServletRequest request, HttpServletResponse response)
* throws IOException, ServletException</li>
* </ul>
* <p>and call one of the methods with a URL like this:</p>
* <code>
* http://localhost:8080/myapp/saveSubscription.do?method=update
* </code>
*
* <p><strong>NOTE</strong> - All of the other mapping characteristics of
* this action must be shared by the various handlers. This places some
* constraints over what types of handlers may reasonably be packaged into
* the same <code>DispatchAction</code> subclass.</p>
*
* @author Niall Pemberton <[EMAIL PROTECTED]>
* @author Craig R. McClanahan
* @version $Revision: 1.1 $ $Date: 2001/03/29 18:40:30 $
*/
public abstract class DispatchAction extends Action {
// ----------------------------------------------------- Instance Variables
/**
* The Class instance of this <code>DispatchAction</code> class.
*/
protected Class clazz = this.getClass();
/**
* The message resources for this package.
*/
protected static MessageResources messages =
MessageResources.getMessageResources
("org.apache.struts.action.LocalStrings");
/**
* The set of Method objects we have introspected for this class,
* keyed by method name. This collection is populated as different
* methods are called, so that introspection needs to occur only
* once per method name.
*/
protected HashMap methods = new HashMap();
/**
* The set of argument type classes for the reflected method call. These
* are the same for all calls, so calculate them only once.
*/
protected Class types[] = {
ActionMapping.class, ActionForm.class,
HttpServletRequest.class, HttpServletResponse.class };
// --------------------------------------------------------- Public Methods
/**
* Process the specified HTTP request, and create the corresponding HTTP
* response (or forward to another web component that will create it).
* Return an <code>ActionForward</code> instance describing where and how
* control should be forwarded, or <code>null</code> if the response has
* already been completed.
*
* @param mapping The ActionMapping used to select this instance
* @param actionForm 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
*
* @exception IOException if an input/output error occurs
* @exception ServletException if a servlet exception occurs
*/
public ActionForward perform(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {
// Identify the request parameter containing the method name
String parameter = mapping.getParameter();
if (parameter == null) {
String message =
messages.getMessage("dispatch.handler", mapping.getPath());
servlet.log(message);
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
message);
return (null);
}
// Identify the method name to be dispatched to
String name = request.getParameter(parameter);
if (name == null) {
String message =
messages.getMessage("dispatch.parameter", mapping.getPath(),
parameter);
servlet.log(message);
response.sendError(HttpServletResponse.SC_BAD_REQUEST,
message);
return (null);
}
// Identify the method object to be dispatched to
Method method = null;
try {
method = getMethod(name);
} catch (NoSuchMethodException e) {
String message =
messages.getMessage("dispatch.method", mapping.getPath(),
name);
servlet.log(message);
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
message);
return (null);
}
// Dispatch to the specified method
ActionForward forward = null;
try {
Object args[] = { mapping, form, request, response };
forward = (ActionForward) method.invoke(this, args);
} catch (ClassCastException e) {
String message =
messages.getMessage("dispatch.return", mapping.getPath(),
name);
servlet.log(message);
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
message);
return (null);
} catch (IllegalAccessException e) {
String message =
messages.getMessage("dispatch.error", mapping.getPath(),
name);
servlet.log(message, e);
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
message);
return (null);
} catch (InvocationTargetException e) {
String message =
messages.getMessage("dispatch.error", mapping.getPath(),
name);
servlet.log(message, e);
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
message);
return (null);
}
// Return the returned ActionForward instance
return (forward);
}
// ----------------------------------------------------- Protected Methods
/**
* Introspect the current class to identify a method of the specified
* name that accepts the same parameter types as the <code>perform()</code>
* method does.
*
* @param name Name of the method to be introspected
*
* @exception NoSuchMethodException if no such method can be found
*/
protected Method getMethod(String name)
throws NoSuchMethodException {
synchronized (methods) {
Method method = (Method) methods.get(name);
if (method == null) {
method = clazz.getMethod(name, types);
methods.put(name, method);
}
return (method);
}
}
}
