|
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.directwebremoting.util.FakeHttpServletResponse;
import org.directwebremoting.util.LocalUtil;
import org.directwebremoting.util.Logger;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.Dispatcher;
import org.apache.struts2.dispatcher.mapper.ActionMapping;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ActionProxy;
import com.opensymphony.xwork2.ActionProxyFactory;
import com.opensymphony.xwork2.Result;
import com.opensymphony.xwork2.config.Configuration;
import com.opensymphony.xwork2.config.ConfigurationException;
import com.opensymphony.xwork2.util.OgnlValueStack;
/**
* This class represents the entry point to all WebWork action invocations. It identifies the
* action to be invoked, prepares the action invocation context and finally wraps the
* result.
* You can configure an IDWRActionProcessor through a context-wide initialization parameter
* dwrActionProcessor that whose methods will be invoked around action invocation.
*
* @author
*/
public class DWRAction
{
/**
* The log stream
*/
private static final Logger log = Logger.getLogger(DWRAction.class);
private static final String DWRACTIONPROCESSOR_INIT_PARAM = "dwrActionProcessor";
private static DWRAction s_instance;
private Dispatcher m_wwDispatcher;
private IDWRActionProcessor m_actionProcessor;
@SuppressWarnings("unchecked")
private DWRAction(ServletContext servletContext) throws ServletException
{
// Dispatcher.initialize(servletContext);
m_wwDispatcher = Dispatcher.getInstance();
if(m_wwDispatcher==null)
{
m_wwDispatcher = new Dispatcher(servletContext, new HashMap());
m_wwDispatcher.init();
Dispatcher.setInstance(m_wwDispatcher);
}
m_actionProcessor = loadActionProcessor(servletContext.getInitParameter (DWRACTIONPROCESSOR_INIT_PARAM));
}
/**
* Entry point for all action invocations.
*
* @param actionDefinition the identification information for the action
* @param params action invocation parameters
* @param request original request
* @param response original response
* @param servletContext current ServletContext
* @return an AjaxResult wrapping invocation result
*
* @throws ServletException thrown if the initialization or invocation of the action fails
*/
public static AjaxResult execute(ActionDefinition actionDefinition, Map params, HttpServletRequest request, HttpServletResponse response, ServletContext servletContext) throws ServletException
{
initialize(servletContext);
return s_instance.doExecute(actionDefinition, params, request, response, servletContext);
}
protected AjaxResult doExecute(ActionDefinition actionDefinition, Map params, HttpServletRequest request, HttpServletResponse response, ServletContext servletContext) throws ServletException
{
FakeHttpServletResponse actionResponse = new FakeHttpServletResponse();
if (null != m_actionProcessor)
{
m_actionProcessor.preProcess(request, response, actionResponse, params);
}
m_wwDispatcher.prepare(request, actionResponse);
ActionInvocation invocation = invokeAction(m_wwDispatcher, request, actionResponse, servletContext, actionDefinition, params);
AjaxResult result = null;
if (actionDefinition.isExecuteResult())
{
// HINT: we have output string
result = getTextResult(actionResponse);
}
else
{
result = new DefaultAjaxDataResult(invocation.getAction());
}
if (null != m_actionProcessor)
{
m_actionProcessor.postProcess(request, response, actionResponse, result);
}
return result;
}
@SuppressWarnings("unchecked")
protected ActionInvocation invokeAction(Dispatcher du, HttpServletRequest request, HttpServletResponse response, ServletContext context, ActionDefinition actionDefinition, Map params) throws ServletException
{
ActionMapping mapping = getActionMapping(actionDefinition, params);
Map extraContext = du.createContextMap(request, response, mapping, context);
// If there was a previous value stack, then create a new copy and pass it in to be used by the new Action
OgnlValueStack stack = (OgnlValueStack) request.getAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY);
if (null != stack)
{
extraContext.put(ActionContext.VALUE_STACK, new OgnlValueStack(stack));
}
try
{
prepareContinuationAction(request, extraContext);
Configuration config = du.getConfigurationManager().getConfiguration();
ActionProxy proxy = config.getContainer().getInstance(ActionProxyFactory.class).createActionProxy(
mapping.getNamespace(), mapping.getName(), extraContext, actionDefinition.isExecuteResult(), false); proxy.setMethod(actionDefinition.getMethod());
request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, proxy.getInvocation().getStack());
// if the ActionMapping says to go straight to a result, do it!
if (mapping.getResult() != null)
{
Result result = mapping.getResult();
result.execute(proxy.getInvocation());
}
else
{
proxy.execute();
}
return proxy.getInvocation();
}
catch (ConfigurationException ce)
{
throw new ServletException("Cannot invoke action '" + actionDefinition.getAction() + "' in namespace '" + actionDefinition.getNamespace() + "'", ce);
}
catch (Exception e)
{
throw new ServletException("Cannot invoke action '" + actionDefinition.getAction() + "' in namespace '" + actionDefinition.getNamespace() + "'", e);
}
finally
{
// If there was a previous value stack then set it back onto the request
if (null != stack)
{
request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, stack);
}
}
}
protected void prepareContinuationAction(HttpServletRequest request, Map extraContext)
{
// String id = request.getParameter(XWorkContinuationConfig.CONTINUE_PARAM);
// if (null != id)
// {
// // remove the continue key from the params - we don't want to bother setting
// // on the value stack since we know it won't work. Besides, this breaks devMode!
// Map params = (Map) extraContext.get(ActionContext.PARAMETERS);
// params.remove(XWorkContinuationConfig.CONTINUE_PARAM);
//
// // and now put the key in the context to be picked up later by XWork
// extraContext.put(XWorkContinuationConfig.CONTINUE_KEY, id);
// }
}
protected ActionMapping getActionMapping(ActionDefinition actionDefinition, Map params)
{
ActionMapping actionMapping = new ActionMapping(actionDefinition.getAction(), actionDefinition.getNamespace(), actionDefinition.getMethod(), params);
return actionMapping;
}
protected AjaxTextResult getTextResult(FakeHttpServletResponse response)
{
DefaultAjaxTextResult result = new DefaultAjaxTextResult();
String text = null;
try
{
text = response.getContentAsString();
}
catch (UnsupportedEncodingException uee)
{
log.warn("Cannot retrieve text output as string", uee);
}
if (null == text)
{
try
{
text = response.getCharacterEncoding() != null ? new String(response.getContentAsByteArray(), response.getCharacterEncoding()) : new String(response.getContentAsByteArray());
}
catch (UnsupportedEncodingException uee)
{
log.warn("Cannot retrieve text output as encoded byte array", uee);
text = new String(response.getContentAsByteArray());
}
}
result.setText(text);
return result;
}
/**
* Performs the one time initialization of the singleton DWRAction.
*
* @param servletContext
* @throws ServletException thrown in case the singleton initialization fails
*/
private static void initialize(ServletContext servletContext) throws ServletException
{
synchronized(DWRAction.class)
{
if (null == s_instance)
{
s_instance = new DWRAction(servletContext);
}
}
}
/**
* Tries to instantiate an IDWRActionProcessor if defined in web.xml.
*
* @param actionProcessorClassName
* @return an instance of IDWRActionProcessor if the init-param is defined or null
* @throws ServletException thrown if the IDWRActionProcessor cannot be loaded and instantiated
*/
private static IDWRActionProcessor loadActionProcessor(String actionProcessorClassName) throws ServletException
{
if (null == actionProcessorClassName || "".equals(actionProcessorClassName))
{
return null;
}
try
{
Class actionProcessorClass = LocalUtil.classForName(actionProcessorClassName);
return (IDWRActionProcessor) actionProcessorClass.newInstance();
}
catch(ClassNotFoundException cnfe)
{
throw new ServletException("Cannot load DWRActionProcessor class '" + actionProcessorClassName + "'", cnfe);
}
catch(IllegalAccessException iae)
{
throw new ServletException("Cannot instantiate DWRActionProcessor class '" + actionProcessorClassName + "'. Default constructor is not visible", iae);
}
catch(InstantiationException ie)
{
throw new ServletException("Cannot instantiate DWRActionProcessor class '" + actionProcessorClassName + "'. No default constructor found", ie);
}
catch(Throwable cause)
{
throw new ServletException("Cannot instantiate DWRActionProcessor class '" + actionProcessorClassName + "'", cause);
}
}
}
|
