org.apache.myfaces.application.jsp.JspViewHandlerImpl Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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,
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.myfaces.application.jsp;
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.Iterator;
import java.util.Locale;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.faces.FacesException;
import javax.faces.FactoryFinder;
import javax.faces.application.Application;
import javax.faces.application.StateManager;
import javax.faces.application.ViewHandler;
import javax.faces.component.UIViewRoot;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.RenderKit;
import javax.faces.render.RenderKitFactory;
import javax.faces.render.ResponseStateManager;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.jstl.core.Config;
import org.apache.myfaces.shared_impl.application.DefaultViewHandlerSupport;
import org.apache.myfaces.shared_impl.application.InvalidViewIdException;
import org.apache.myfaces.shared_impl.application.ViewHandlerSupport;
import org.apache.myfaces.shared_impl.config.MyfacesConfig;
import org.apache.myfaces.shared_impl.renderkit.html.util.JavascriptUtils;
/**
* Implementation of the ViewHandler interface that knows how to use JSP pages
* as the view templating mechanism.
*
* This implementation works tightly together with the various JSP TagHandler classes
* to implement the behaviour mandated by the ViewHandler specification.
*
* Rendering of a view is done in two parts: first a jsp-generated servlet is invoked
* to create or refresh a jsf component tree, then the component tree is walked to generate
* the output to send to the user.
*
* The invoked servlet is the one generated from the jsp file which corresponds to the
* viewId of the view being rendered. As is normal for jsp, this servlet alternates between
* writing literal text to the response output stream and invoking "tag handler" classes
* representing the jsp tags that were present in the page. This servlet is not aware of
* JSF at all.
*
* On the first visit to a view, when each JSF taghandler is invoked, the corresponding
* JSF component will not yet exist so it is created and added to the current view tree.
* Each JSF taghandler also marks itself as having "buffered body content", which means that
* after the start-tag is executed a temporary output stream is installed for the response.
* Any output generated by the jsp-servlet therefore gets written into a memory buffer
* rather than sent via the network socket to the sender of the request. When the end
* of the JSF tag is encountered, the JSF tag checks whether any such body text did exist,
* and if so it creates a transient f:verbatim component and inserts it into the component
* tree. The final result is that after this "first pass" a component tree exists which has
* all the JSF components in it, plus a bunch of auto-generated f:verbatim components that
* hold all plain text, or output generated by non-jsf jsp tags. Absolutely NO output has
* yet been sent to the real response stream.
*
* On later visits to the same view, the component tree already exists (has been restored).
* However the "verbatim" components holding static text are not present as they were
* marked "transient" (not keeping them reduces the amount of memory required to "save state").
* Note that these components are not needed for any phase prior to RENDER because they
* are not "input" components. When the jsp-generated servlet is executed, JSF taghandlers
* that are invoked will simply verify that a corresponding component already exists in the
* view-tree rather than creating a new one. However the "body buffering" occurs again, so
* that the appropriate transient verbatim components are once again created and inserted into
* the tree.
*
* Regardless of whether the view is new or restored, the rendered output can now be generated
* simply by walking the component tree and invoking the encodeBegin/encodeChildren/encodeEnd
* methods on each component. The static components simply output their contained text.
*
* Notes for JSF1.1 users: the new two-phase approach that uses "output buffering" to capture
* non-JSF output is rather like wrapping all non-jsf components in an invisible f:verbatim tag.
* Although that doesn't sound like a big change, it allows processing to occur in two passes
* rather than one. And that means that before any component is rendered the entire component
* tree already exists. This solves a number of JSF1.1 problems, including output-ordering
* problems between text and jsf components, and errors when using the "for" attribute of a
* label to reference a component later in the page. It does introduce a performance penalty;
* non-JSF-generated output now gets buffered rather than being streamed directly to the
* user.
*
* @author Thomas Spiegl (latest modification by $Author: lu4242 $)
* @author Bruno Aranda
* @version $Revision: 966305 $ $Date: 2010-07-21 11:39:15 -0500 (Wed, 21 Jul 2010) $
*/
public class JspViewHandlerImpl extends ViewHandler
{
//private static final Log log = LogFactory.getLog(JspViewHandlerImpl.class);
private static final Logger log = Logger.getLogger(JspViewHandlerImpl.class.getName());
public static final String FORM_STATE_MARKER = "";
public static final int FORM_STATE_MARKER_LEN = FORM_STATE_MARKER.length();
private static final String AFTER_VIEW_TAG_CONTENT_PARAM = JspViewHandlerImpl.class + ".AFTER_VIEW_TAG_CONTENT";
private ViewHandlerSupport _viewHandlerSupport;
public JspViewHandlerImpl()
{
if (log.isLoggable(Level.FINEST))
log.finest("New ViewHandler instance created");
}
/**
* @param viewHandlerSupport
* the viewHandlerSupport to set
*/
public void setViewHandlerSupport(ViewHandlerSupport viewHandlerSupport)
{
_viewHandlerSupport = viewHandlerSupport;
}
/**
* @return the viewHandlerSupport
*/
protected ViewHandlerSupport getViewHandlerSupport()
{
if (_viewHandlerSupport == null)
{
_viewHandlerSupport = new DefaultViewHandlerSupport();
}
return _viewHandlerSupport;
}
/**
* Get the locales specified as acceptable by the original request, compare them to the
* locales supported by this Application and return the best match.
*/
@Override
public Locale calculateLocale(FacesContext facesContext)
{
Application application = facesContext.getApplication();
for (Iterator requestLocales = facesContext.getExternalContext().getRequestLocales(); requestLocales
.hasNext();)
{
Locale requestLocale = requestLocales.next();
for (Iterator supportedLocales = application.getSupportedLocales(); supportedLocales.hasNext();)
{
Locale supportedLocale = supportedLocales.next();
// higher priority to a language match over an exact match
// that occures further down (see Jstl Reference 1.0 8.3.1)
if (requestLocale.getLanguage().equals(supportedLocale.getLanguage())
&& (supportedLocale.getCountry() == null || supportedLocale.getCountry().length() == 0))
{
return supportedLocale;
}
else if (supportedLocale.equals(requestLocale))
{
return supportedLocale;
}
}
}
Locale defaultLocale = application.getDefaultLocale();
return defaultLocale != null ? defaultLocale : Locale.getDefault();
}
@Override
public String calculateRenderKitId(FacesContext facesContext)
{
Object renderKitId = facesContext.getExternalContext().getRequestMap().get(
ResponseStateManager.RENDER_KIT_ID_PARAM);
if (renderKitId == null)
{
renderKitId = facesContext.getApplication().getDefaultRenderKitId();
}
if (renderKitId == null)
{
renderKitId = RenderKitFactory.HTML_BASIC_RENDER_KIT;
}
return renderKitId.toString();
}
/**
* Create a UIViewRoot object and return it; the returned object has no children.
*
* As required by the spec, the returned object inherits locale and renderkit settings from
* the viewRoot currently configured for the facesContext (if any). This means that on navigation
* from one view to another these settings are "inherited".
*/
@Override
public UIViewRoot createView(FacesContext facesContext, String viewId)
{
String calculatedViewId = viewId;
try
{
calculatedViewId = getViewHandlerSupport().calculateViewId(facesContext, viewId);
}
catch (InvalidViewIdException e)
{
sendSourceNotFound(facesContext, e.getMessage());
}
Application application = facesContext.getApplication();
ViewHandler applicationViewHandler = application.getViewHandler();
Locale currentLocale = null;
String currentRenderKitId = null;
UIViewRoot uiViewRoot = facesContext.getViewRoot();
if (uiViewRoot != null)
{
// Remember current locale and renderKitId
currentLocale = uiViewRoot.getLocale();
currentRenderKitId = uiViewRoot.getRenderKitId();
}
uiViewRoot = (UIViewRoot) application.createComponent(UIViewRoot.COMPONENT_TYPE);
uiViewRoot.setViewId(calculatedViewId);
if (currentLocale != null)
{
// set old locale
uiViewRoot.setLocale(currentLocale);
}
else
{
// calculate locale
uiViewRoot.setLocale(applicationViewHandler.calculateLocale(facesContext));
}
if (currentRenderKitId != null)
{
// set old renderKit
uiViewRoot.setRenderKitId(currentRenderKitId);
}
else
{
// calculate renderKit
uiViewRoot.setRenderKitId(applicationViewHandler.calculateRenderKitId(facesContext));
}
if (log.isLoggable(Level.FINEST))
log.finest("Created view " + viewId);
return uiViewRoot;
}
private void sendSourceNotFound(FacesContext context, String message)
{
HttpServletResponse response = (HttpServletResponse) context.getExternalContext().getResponse();
try
{
context.responseComplete();
response.sendError(HttpServletResponse.SC_NOT_FOUND, message);
}
catch (IOException ioe)
{
throw new FacesException(ioe);
}
}
/**
* Return a string containing a webapp-relative URL that the user can invoke
* to render the specified view.
*
* URLs and ViewIds are not quite the same; for example a url of "/foo.jsf"
* or "/faces/foo.jsp" may be needed to access the view "/foo.jsp".
*
* This method simply delegates to ViewHandlerSupport.calculateActionURL.
*/
@Override
public String getActionURL(FacesContext facesContext, String viewId)
{
return getViewHandlerSupport().calculateActionURL(facesContext, viewId);
}
@Override
public String getResourceURL(FacesContext facesContext, String path)
{
if (path.length() > 0 && path.charAt(0) == '/')
{
return facesContext.getExternalContext().getRequestContextPath() + path;
}
return path;
}
/**
* Generate output to the user by combining the data in the jsp-page specified by viewToRender
* with the existing JSF component tree (if any).
*
* As described in the class documentation, this first runs the jsp-generated servlet to
* create or enhance the JSF component tree - including verbatim nodes for any non-jsf
* data in that page.
*
* The component tree is then walked to generate the appropriate output for each component.
*/
@Override
public void renderView(FacesContext facesContext, UIViewRoot viewToRender) throws IOException, FacesException
{
if (viewToRender == null)
{
log.severe("viewToRender must not be null");
throw new NullPointerException("viewToRender must not be null");
}
// do not render the view if the rendered attribute for the view is false
if (!viewToRender.isRendered())
{
if (log.isLoggable(Level.FINEST))
log.finest("View is not rendered");
return;
}
ExternalContext externalContext = facesContext.getExternalContext();
String viewId = facesContext.getViewRoot().getViewId();
if (log.isLoggable(Level.FINEST))
log.finest("Rendering JSP view: " + viewId);
ServletResponse response = (ServletResponse) externalContext.getResponse();
ServletRequest request = (ServletRequest) externalContext.getRequest();
Locale locale = viewToRender.getLocale();
response.setLocale(locale);
Config.set(request, Config.FMT_LOCALE, facesContext.getViewRoot().getLocale());
if(!buildView(response, externalContext, viewId)) {
//building the view was unsuccessful - an exception occurred during rendering
//we need to jump out
return;
}
// handle character encoding as of section 2.5.2.2 of JSF 1.1
if (externalContext.getRequest() instanceof HttpServletRequest)
{
HttpServletRequest httpServletRequest = (HttpServletRequest) externalContext.getRequest();
HttpSession session = httpServletRequest.getSession(false);
if (session != null)
{
session.setAttribute(ViewHandler.CHARACTER_ENCODING_KEY, response.getCharacterEncoding());
}
}
// render the view in this method (since JSF 1.2)
RenderKitFactory renderFactory = (RenderKitFactory) FactoryFinder.getFactory(FactoryFinder.RENDER_KIT_FACTORY);
RenderKit renderKit = renderFactory.getRenderKit(facesContext, viewToRender.getRenderKitId());
ResponseWriter responseWriter = facesContext.getResponseWriter();
if (responseWriter == null)
{
responseWriter = renderKit.createResponseWriter(response.getWriter(), null,
((HttpServletRequest) externalContext.getRequest()).getCharacterEncoding());
facesContext.setResponseWriter(responseWriter);
}
ResponseWriter oldResponseWriter = responseWriter;
StateMarkerAwareWriter stateAwareWriter = null;
StateManager stateManager = facesContext.getApplication().getStateManager();
if (stateManager.isSavingStateInClient(facesContext))
{
stateAwareWriter = new StateMarkerAwareWriter();
// Create a new response-writer using as an underlying writer the stateAwareWriter
// Effectively, all output will be buffered in the stateAwareWriter so that later
// this writer can replace the state-markers with the actual state.
responseWriter = hookInStateAwareWriter(
oldResponseWriter, stateAwareWriter, renderKit, externalContext);
facesContext.setResponseWriter(responseWriter);
}
actuallyRenderView(facesContext, viewToRender);
facesContext.setResponseWriter(oldResponseWriter);
//We're done with the document - now we can write all content
//to the response, properly replacing the state-markers on the way out
//by using the stateAwareWriter
if (stateManager.isSavingStateInClient(facesContext))
{
stateAwareWriter.flushToWriter(response.getWriter());
}
else
{
stateManager.saveView(facesContext);
}
// Final step - we output any content in the wrappedResponse response from above to the response,
// removing the wrappedResponse response from the request, we don't need it anymore
ServletViewResponseWrapper afterViewTagResponse = (ServletViewResponseWrapper) externalContext.getRequestMap().get(
AFTER_VIEW_TAG_CONTENT_PARAM);
externalContext.getRequestMap().remove(AFTER_VIEW_TAG_CONTENT_PARAM);
if (afterViewTagResponse != null)
{
afterViewTagResponse.flushToWriter(response.getWriter(),
facesContext.getExternalContext().getResponseCharacterEncoding());
}
response.flushBuffer();
}
/**
* Render the view now - properly setting and resetting the response writer
*/
private void actuallyRenderView(FacesContext facesContext,
UIViewRoot viewToRender) throws IOException {
// Set the new ResponseWriter into the FacesContext, saving the old one aside.
ResponseWriter responseWriter = facesContext.getResponseWriter();
//Now we actually render the document
// Call startDocument() on the ResponseWriter.
responseWriter.startDocument();
// Call encodeAll() on the UIViewRoot
viewToRender.encodeAll(facesContext);
// Call endDocument() on the ResponseWriter
responseWriter.endDocument();
responseWriter.flush();
}
/**Create a new response-writer using as an underlying writer the stateAwareWriter
* Effectively, all output will be buffered in the stateAwareWriter so that later
* this writer can replace the state-markers with the actual state.
*
* If the FacesContext has a non-null ResponseWriter create a new writer using its
* cloneWithWriter() method, passing the response's Writer as the argument.
* Otherwise, use the current RenderKit to create a new ResponseWriter.
*
* @param oldResponseWriter
* @param stateAwareWriter
* @param renderKit
* @param externalContext
* @return
*/
private ResponseWriter hookInStateAwareWriter(ResponseWriter oldResponseWriter, StateMarkerAwareWriter stateAwareWriter, RenderKit renderKit, ExternalContext externalContext) {
return oldResponseWriter.cloneWithWriter(stateAwareWriter);
/*
ResponseWriter newResponseWriter;
if (oldResponseWriter != null)
{
newResponseWriter = oldResponseWriter.cloneWithWriter(stateAwareWriter);
}
else
{
if (log.isTraceEnabled())
log.trace("Creating new ResponseWriter");
newResponseWriter = renderKit.createResponseWriter(stateAwareWriter, null,
((HttpServletRequest) externalContext.getRequest()).getCharacterEncoding());
}
return newResponseWriter;
*/
}
/**Build the view-tree before rendering.
* This is done by dispatching to the underlying JSP-page, effectively processing it, creating
* components out of any text in between JSF components (not rendering the text to the output of course, this
* will happen later while rendering), attaching these components
* to the component tree, and buffering any content after the view-root.
*
* @param response The current response - it will be replaced while the view-building happens (we want the text in the component tree, not on the actual servlet output stream)
* @param externalContext The external context where the response will be replaced while building
* @param viewId The view-id to dispatch to
* @return true if successfull, false if an error occurred during rendering
* @throws IOException
*/
private boolean buildView(ServletResponse response, ExternalContext externalContext, String viewId) throws IOException {
ServletViewResponseWrapper wrappedResponse = new ServletViewResponseWrapper((HttpServletResponse) response);
externalContext.setResponse(wrappedResponse);
try
{
externalContext.dispatch(viewId);
}
finally
{
externalContext.setResponse(response);
}
boolean errorResponse = wrappedResponse.getStatus() < 200 || wrappedResponse.getStatus() > 299;
if (errorResponse)
{
wrappedResponse.flushToWrappedResponse();
return false;
}
// store the wrapped response in the request, so it is thread-safe
externalContext.getRequestMap().put(AFTER_VIEW_TAG_CONTENT_PARAM, wrappedResponse);
return true;
}
/**
* Just invoke StateManager.restoreView.
*/
@Override
public UIViewRoot restoreView(FacesContext facesContext, String viewId)
{
Application application = facesContext.getApplication();
ViewHandler applicationViewHandler = application.getViewHandler();
String renderKitId = applicationViewHandler.calculateRenderKitId(facesContext);
String calculatedViewId = getViewHandlerSupport().calculateViewId(facesContext, viewId);
UIViewRoot viewRoot = application.getStateManager().restoreView(facesContext, calculatedViewId, renderKitId);
return viewRoot;
}
/**
* Writes a state marker that is replaced later by one or more hidden form
* inputs.
*
* The problem with html is that the only place to encode client-side state is
* in a hidden html input field. However when a form is submitted, only the fields
* within a particular form are sent; fields in other forms are not sent. Therefore
* the view tree state must be written into every form in the page. This method
* is therefore invoked at the end of every form.
*
* Theoretically the state of a component tree will not change after rendering
* starts. Therefore it is possible to create a serialized representation of that
* state at the start of the rendering phase (or when first needed) and output it
* whenever needed as described above. However this is not currently implemented;
* instead the entire page being generated is buffered, and a "marker" string is
* output instead of the tree state. After the rendering pass is complete the component
* final tree state is computed and the buffer is then post-processed to replace the
* "marker" strings with the real data.
*
* This method also supports "javascript viewstate". TODO: document this.
*
* @param facesContext
* @throws IOException
*/
@Override
public void writeState(FacesContext facesContext) throws IOException
{
StateManager stateManager = facesContext.getApplication().getStateManager();
if (stateManager.isSavingStateInClient(facesContext))
{
// Only write state marker if javascript view state is disabled
ExternalContext extContext = facesContext.getExternalContext();
if (!(JavascriptUtils.isJavascriptAllowed(extContext) && MyfacesConfig.getCurrentInstance(extContext).isViewStateJavascript())) {
facesContext.getResponseWriter().write(FORM_STATE_MARKER);
}
}
else
{
stateManager.writeState(facesContext, new Object[2]);
}
}
/**
* Writes the response and replaces the state marker tags with the state information for the current context
*/
private static class StateMarkerAwareWriter extends Writer
{
private StringBuilder buf;
public StateMarkerAwareWriter()
{
this.buf = new StringBuilder();
}
@Override
public void close() throws IOException
{
}
@Override
public void flush() throws IOException
{
}
@Override
public void write(char[] cbuf, int off, int len) throws IOException
{
if ((off < 0) || (off > cbuf.length) || (len < 0) ||
((off + len) > cbuf.length) || ((off + len) < 0)) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return;
}
buf.append(cbuf, off, len);
}
public StringBuilder getStringBuilder()
{
return buf;
}
public void flushToWriter(Writer writer) throws IOException
{
FacesContext facesContext = FacesContext.getCurrentInstance();
StateManager stateManager = facesContext.getApplication().getStateManager();
StringWriter stateWriter = new StringWriter();
ResponseWriter realWriter = facesContext.getResponseWriter();
facesContext.setResponseWriter(realWriter.cloneWithWriter(stateWriter));
Object serializedView = stateManager.saveView(facesContext);
stateManager.writeState(facesContext, serializedView);
facesContext.setResponseWriter(realWriter);
StringBuilder contentBuffer = getStringBuilder();
String state = stateWriter.getBuffer().toString();
ExternalContext extContext = facesContext.getExternalContext();
if (JavascriptUtils.isJavascriptAllowed(extContext) && MyfacesConfig.getCurrentInstance(extContext).isViewStateJavascript()) {
// If javascript viewstate is enabled no state markers were written
write(contentBuffer, 0, contentBuffer.length(), writer);
writer.write(state);
} else {
// If javascript viewstate is disabled state markers must be replaced
int lastFormMarkerPos = 0;
int formMarkerPos = 0;
// Find all state markers and write out actual state instead
while ((formMarkerPos = contentBuffer.indexOf(FORM_STATE_MARKER, formMarkerPos)) > -1)
{
// Write content before state marker
write(contentBuffer, lastFormMarkerPos, formMarkerPos, writer);
// Write state and move position in buffer after marker
writer.write(state);
formMarkerPos += FORM_STATE_MARKER_LEN;
lastFormMarkerPos = formMarkerPos;
}
// Write content after last state marker
if (lastFormMarkerPos < contentBuffer.length()) {
write(contentBuffer, lastFormMarkerPos, contentBuffer.length(), writer);
}
}
}
/**
* Writes the content of the specified StringBuffer from index
* beginIndex to index endIndex - 1.
*
* @param contentBuffer the StringBuffer to copy content from
* @param beginIndex the beginning index, inclusive.
* @param endIndex the ending index, exclusive
* @param writer the Writer to write to
* @throws IOException if an error occurs writing to specified Writer
*/
private void write(StringBuilder contentBuffer, int beginIndex, int endIndex, Writer writer) throws IOException {
int index = beginIndex;
int bufferSize = 2048;
char[] bufToWrite = new char[bufferSize];
while (index < endIndex)
{
int maxSize = Math.min(bufferSize, endIndex - index);
contentBuffer.getChars(index, index + maxSize, bufToWrite, 0);
writer.write(bufToWrite, 0, maxSize);
index += bufferSize;
}
}
}
}