/*
* Copyright 2004-2005 Graeme Rocher
*
* 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.grails.web.pages.ext.jsp;
import groovy.lang.Binding;
import java.io.IOException;
import java.io.Writer;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.*;
import javax.el.ELContext;
import javax.servlet.GenericServlet;
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
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.*;
import javax.servlet.jsp.el.ELException;
import javax.servlet.jsp.el.ExpressionEvaluator;
import javax.servlet.jsp.el.VariableResolver;
import javax.servlet.jsp.tagext.BodyContent;
import org.grails.web.pages.GroovyPage;
import org.grails.web.servlet.mvc.GrailsWebRequest;
import org.springframework.util.Assert;
import org.springframework.web.context.request.RequestContextHolder;
/**
* A JSP PageContext implementation for use with GSP.
*
* @author Graeme Rocher
* @since 1.1
*/
public class GroovyPagesPageContext extends PageContext {
private static final Enumeration EMPTY_ENUMERATION = new Enumeration() {
@Override
public boolean hasMoreElements() {
return false;
}
@Override
public Object nextElement() {
return new NoSuchElementException();
}
};
private ServletContext servletContext;
private Servlet servlet;
private HttpServletRequest request;
private HttpServletResponse response;
private ServletConfig servletconfig;
private Binding pageScope;
private GrailsWebRequest webRequest;
private JspWriter jspOut;
private Deque outStack = new ArrayDeque();
@SuppressWarnings("rawtypes")
private List tags = new ArrayList();
private HttpSession session;
public GroovyPagesPageContext(Servlet pagesServlet, Binding pageScope) {
Assert.notNull(pagesServlet, "GroovyPagesPageContext class requires a reference to the GSP servlet");
webRequest = (GrailsWebRequest) RequestContextHolder.currentRequestAttributes();
servletContext = webRequest.getServletContext();
request = webRequest.getCurrentRequest();
response = webRequest.getCurrentResponse();
servlet = pagesServlet;
servletconfig = pagesServlet.getServletConfig();
this.pageScope = pageScope;
session = request.getSession(false);
// setup initial writer
pushWriter(new JspWriterDelegate(webRequest.getOut()));
// Register page attributes as per JSP spec
setAttribute(REQUEST, request);
setAttribute(RESPONSE, response);
if (session != null) {
setAttribute(SESSION, session);
}
setAttribute(PAGE, servlet);
setAttribute(CONFIG, servlet.getServletConfig());
setAttribute(PAGECONTEXT, this);
setAttribute(APPLICATION, servletContext);
}
void popWriter() {
outStack.pop();
jspOut = (JspWriter) outStack.peek();
setCurrentOut();
}
void pushWriter(JspWriter out) {
outStack.push(out);
jspOut = out;
setCurrentOut();
}
private void setCurrentOut() {
setAttribute(OUT, jspOut);
setAttribute(GroovyPage.OUT, jspOut);
webRequest.setOut(jspOut);
}
Object peekTopTag(Class<?> tagClass) {
for (ListIterator<?> iter = tags.listIterator(tags.size()); iter.hasPrevious();) {
Object tag = iter.previous();
if (tagClass.isInstance(tag)) {
return tag;
}
}
return null;
}
void popTopTag() {
tags.remove(tags.size() - 1);
}
@SuppressWarnings("unchecked")
void pushTopTag(Object tag) {
tags.add(tag);
}
@Override
public BodyContent pushBody() {
BodyContent bc = new BodyContentImpl(getOut(), true);
pushWriter(bc);
return bc;
}
@Override
public JspWriter popBody() {
popWriter();
return (JspWriter) getAttribute(OUT);
}
@SuppressWarnings("serial")
public GroovyPagesPageContext(Binding pageScope) {
this(new GenericServlet() {
@Override
public ServletConfig getServletConfig() {
return this;
}
@Override
public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
// do nothing;
}
}, pageScope != null ? pageScope : new Binding());
}
public GroovyPagesPageContext() {
this(new Binding());
}
@Override
public void initialize(Servlet s, ServletRequest servletRequest, ServletResponse servletResponse,
String errorPageURL, boolean needSession, int bufferSize, boolean autoFlush) {
// do nothing, not constructed for container
}
@Override
public void release() {
// do nothing, not released by container
}
@Override
public HttpSession getSession() {
return request.getSession(false);
}
@Override
public Object getPage() {
return servlet;
}
@Override
public ServletRequest getRequest() {
return request;
}
@Override
public ServletResponse getResponse() {
return response;
}
@Override
public Exception getException() {
throw new UnsupportedOperationException();
}
@Override
public ServletConfig getServletConfig() {
return servletconfig;
}
@Override
public ServletContext getServletContext() {
return servletContext;
}
@Override
public void forward(String url) throws ServletException, IOException {
request.getRequestDispatcher(url).forward(request, response);
}
@Override
public void include(String url) throws ServletException, IOException {
include(url, false);
}
@Override
public void include(String url, boolean flush) throws ServletException, IOException {
request.getRequestDispatcher(url).include(request, response);
}
@Override
public void handlePageException(Exception e) throws ServletException, IOException {
throw new UnsupportedOperationException();
}
@Override
public void handlePageException(Throwable throwable) throws ServletException, IOException {
throw new UnsupportedOperationException();
}
@Override
public void setAttribute(String name, Object value) {
Assert.notNull(name, "Attribute name cannot be null");
pageScope.setVariable(name, value);
}
@Override
public void setAttribute(String name, Object value, int scope) {
Assert.notNull(name, "Attribute name cannot be null");
switch (scope) {
case PAGE_SCOPE:
setAttribute(name, value);
break;
case REQUEST_SCOPE:
request.setAttribute(name,value);
break;
case SESSION_SCOPE:
request.getSession(true).setAttribute(name, value);
break;
case APPLICATION_SCOPE:
servletContext.setAttribute(name, value);
break;
default:
setAttribute(name, value);
}
}
@Override
public Object getAttribute(String name) {
Assert.notNull(name, "Attribute name cannot be null");
if (pageScope.getVariables().containsKey(name)) {
return pageScope.getVariable(name);
}
return null;
}
@Override
public Object getAttribute(String name, int scope) {
Assert.notNull(name, "Attribute name cannot be null");
switch (scope) {
case PAGE_SCOPE: return getAttribute(name);
case REQUEST_SCOPE: return request.getAttribute(name);
case SESSION_SCOPE: return request.getSession(true).getAttribute(name);
case APPLICATION_SCOPE: return servletContext.getAttribute(name);
default: return getAttribute(name);
}
}
@Override
public Object findAttribute(String name) {
Assert.notNull(name, "Attribute name cannot be null");
int scope = getAttributesScope(name);
if (scope > 0) {
return getAttribute(name, scope);
}
return null;
}
@Override
public void removeAttribute(String name) {
Assert.notNull(name, "Attribute name cannot be null");
pageScope.getVariables().remove(name);
}
@Override
public void removeAttribute(String name, int scope) {
Assert.notNull(name, "Attribute name cannot be null");
switch (scope) {
case PAGE_SCOPE:
removeAttribute(name);
break;
case REQUEST_SCOPE:
request.removeAttribute(name);
break;
case SESSION_SCOPE:
HttpSession httpSession = request.getSession(false);
if (httpSession != null) {
httpSession.removeAttribute(name);
}
break;
case APPLICATION_SCOPE:
servletContext.removeAttribute(name);
break;
default:
removeAttribute(name);
}
}
@Override
public int getAttributesScope(String name) {
Assert.notNull(name, "Attribute name cannot be null");
if (pageScope.getVariables().containsKey(name)) {
return PAGE_SCOPE;
}
if (request.getAttribute(name) != null) {
return REQUEST_SCOPE;
}
HttpSession httpSession = request.getSession(false);
if (httpSession != null && httpSession.getAttribute(name) != null) {
return SESSION_SCOPE;
}
if (servletContext.getAttribute(name) !=null) {
return APPLICATION_SCOPE;
}
return 0;
}
@SuppressWarnings("rawtypes")
@Override
public Enumeration getAttributeNamesInScope(int scope) {
switch (scope) {
case PAGE_SCOPE:
final Iterator i = pageScope.getVariables().keySet().iterator();
return new Enumeration() {
@Override
public boolean hasMoreElements() {
return i.hasNext();
}
@Override
public Object nextElement() {
return i.next();
}
};
case REQUEST_SCOPE:
return request.getAttributeNames();
case SESSION_SCOPE:
HttpSession httpSession = request.getSession(false);
if (httpSession != null) {
return httpSession.getAttributeNames();
}
else {
return EMPTY_ENUMERATION;
}
case APPLICATION_SCOPE:
return servletContext.getAttributeNames();
}
return EMPTY_ENUMERATION;
}
@Override
public JspWriter getOut() {
Writer out = webRequest.getOut();
if (out instanceof JspWriter) {
return (JspWriter)out;
}
out = new JspWriterDelegate(out);
webRequest.setOut(out);
return (JspWriter)out;
}
@Override
public ExpressionEvaluator getExpressionEvaluator() {
try {
Class<?> type = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
public ClassLoader run() {
return Thread.currentThread().getContextClassLoader();
}
}).loadClass("org.apache.commons.el.ExpressionEvaluatorImpl");
return (ExpressionEvaluator) type.newInstance();
}
catch (Exception e) {
throw new UnsupportedOperationException("In order for the getExpressionEvaluator() " +
"method to work, you must have downloaded the apache commons-el jar and " +
"made it available in the classpath.");
}
}
@Override
public VariableResolver getVariableResolver() {
final PageContext ctx = this;
return new VariableResolver() {
public Object resolveVariable(String name) throws ELException {
return ctx.findAttribute(name);
}
};
}
static {
if (JspFactory.getDefaultFactory() == null) {
JspFactory.setDefaultFactory(new GroovyPagesJspFactory());
}
}
private ELContext elContext;
public ELContext getELContext() {
if (elContext == null) {
JspApplicationContext jspContext = JspFactory.getDefaultFactory().getJspApplicationContext(getServletContext());
if (jspContext instanceof GroovyPagesJspApplicationContext) {
elContext = ((GroovyPagesJspApplicationContext)jspContext).createELContext(this);
elContext.putContext( JspContext.class, this );
}
else {
throw new IllegalStateException("Unable to create ELContext for a JspApplicationContext. It must be an instance of [GroovyPagesJspApplicationContext] do not override JspFactory.setDefaultFactory()!");
}
}
return elContext;
}
}