https://tomcat.apache.org/: Tomcat Servlet Engine Core Classes and Standard implementations 
/*
 * 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, 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.catalina.core;

import java.io.IOException;
import java.io.PrintWriter;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;

import jakarta.servlet.AsyncContext;
import jakarta.servlet.DispatcherType;
import jakarta.servlet.RequestDispatcher;
import jakarta.servlet.Servlet;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletRequestWrapper;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.ServletResponseWrapper;
import jakarta.servlet.UnavailableException;
import jakarta.servlet.http.HttpServletMapping;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import org.apache.catalina.AsyncDispatcher;
import org.apache.catalina.Context;
import org.apache.catalina.Globals;
import org.apache.catalina.Wrapper;
import org.apache.catalina.connector.ClientAbortException;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.RequestFacade;
import org.apache.catalina.connector.Response;
import org.apache.catalina.connector.ResponseFacade;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.res.StringManager;


Standard implementation of RequestDispatcher that allows a
request to be forwarded to a different resource to create the ultimate
response, or to include the output of another resource in the response
from this resource.  This implementation allows application level servlets
to wrap the request and/or response objects that are passed on to the
called resource, as long as the wrapping classes extend
jakarta.servlet.ServletRequestWrapper and
jakarta.servlet.ServletResponseWrapper.

Author:Craig R. McClanahan
/**
 * Standard implementation of <code>RequestDispatcher</code> that allows a
 * request to be forwarded to a different resource to create the ultimate
 * response, or to include the output of another resource in the response
 * from this resource.  This implementation allows application level servlets
 * to wrap the request and/or response objects that are passed on to the
 * called resource, as long as the wrapping classes extend
 * <code>jakarta.servlet.ServletRequestWrapper</code> and
 * <code>jakarta.servlet.ServletResponseWrapper</code>.
 *
 * @author Craig R. McClanahan
 */
final class ApplicationDispatcher implements AsyncDispatcher, RequestDispatcher {

    protected class PrivilegedForward
            implements PrivilegedExceptionAction<Void> {
        private final ServletRequest request;
        private final ServletResponse response;

        PrivilegedForward(ServletRequest request, ServletResponse response) {
            this.request = request;
            this.response = response;
        }

        @Override
        public Void run() throws java.lang.Exception {
            doForward(request,response);
            return null;
        }
    }

    protected class PrivilegedInclude implements
            PrivilegedExceptionAction<Void> {
        private final ServletRequest request;
        private final ServletResponse response;

        PrivilegedInclude(ServletRequest request, ServletResponse response) {
            this.request = request;
            this.response = response;
        }

        @Override
        public Void run() throws ServletException, IOException {
            doInclude(request, response);
            return null;
        }
    }

    protected class PrivilegedDispatch implements
            PrivilegedExceptionAction<Void> {
        private final ServletRequest request;
        private final ServletResponse response;

        PrivilegedDispatch(ServletRequest request, ServletResponse response) {
            this.request = request;
            this.response = response;
        }

        @Override
        public Void run() throws ServletException, IOException {
            doDispatch(request, response);
            return null;
        }
    }


    
Used to pass state when the request dispatcher is used. Using instance
variables causes threading issues and state is too complex to pass and
return single ServletRequest or ServletResponse objects.

/**
     * Used to pass state when the request dispatcher is used. Using instance
     * variables causes threading issues and state is too complex to pass and
     * return single ServletRequest or ServletResponse objects.
     */
    private static class State {
        State(ServletRequest request, ServletResponse response,
                boolean including) {
            this.outerRequest = request;
            this.outerResponse = response;
            this.including = including;
        }

        
The outermost request that will be passed on to the invoked servlet.

/**
         * The outermost request that will be passed on to the invoked servlet.
         */
        ServletRequest outerRequest = null;


        
The outermost response that will be passed on to the invoked servlet.

/**
         * The outermost response that will be passed on to the invoked servlet.
         */
        ServletResponse outerResponse = null;

        
The request wrapper we have created and installed (if any).

/**
         * The request wrapper we have created and installed (if any).
         */
        ServletRequest wrapRequest = null;


        
The response wrapper we have created and installed (if any).

/**
         * The response wrapper we have created and installed (if any).
         */
        ServletResponse wrapResponse = null;

        
Are we performing an include() instead of a forward()?

/**
         * Are we performing an include() instead of a forward()?
         */
        boolean including = false;

        
Outermost HttpServletRequest in the chain

/**
         * Outermost HttpServletRequest in the chain
         */
        HttpServletRequest hrequest = null;

        
Outermost HttpServletResponse in the chain

/**
         * Outermost HttpServletResponse in the chain
         */
        HttpServletResponse hresponse = null;
    }

    // ----------------------------------------------------------- Constructors


    
Construct a new instance of this class, configured according to the
specified parameters.  If both servletPath and pathInfo are
null, it will be assumed that this RequestDispatcher
was acquired by name, rather than by path.

Params:
  • wrapper – The Wrapper associated with the resource that will
 be forwarded to or included (required)
  • requestURI – The request URI to this resource (if any)
  • servletPath – The revised servlet path to this resource (if any)
  • pathInfo – The revised extra path information to this resource
 (if any)
  • queryString – Query string parameters included with this request
 (if any)
  • mapping – The mapping for this resource (if any)
  • name – Servlet name (if a named dispatcher was created)
 else null
/**
     * Construct a new instance of this class, configured according to the
     * specified parameters.  If both servletPath and pathInfo are
     * <code>null</code>, it will be assumed that this RequestDispatcher
     * was acquired by name, rather than by path.
     *
     * @param wrapper The Wrapper associated with the resource that will
     *  be forwarded to or included (required)
     * @param requestURI The request URI to this resource (if any)
     * @param servletPath The revised servlet path to this resource (if any)
     * @param pathInfo The revised extra path information to this resource
     *  (if any)
     * @param queryString Query string parameters included with this request
     *  (if any)
     * @param mapping The mapping for this resource (if any)
     * @param name Servlet name (if a named dispatcher was created)
     *  else <code>null</code>
     */
    public ApplicationDispatcher
        (Wrapper wrapper, String requestURI, String servletPath,
         String pathInfo, String queryString, HttpServletMapping mapping, String name) {

        super();

        // Save all of our configuration parameters
        this.wrapper = wrapper;
        this.context = (Context) wrapper.getParent();
        this.requestURI = requestURI;
        this.servletPath = servletPath;
        this.pathInfo = pathInfo;
        this.queryString = queryString;
        this.mapping = mapping;
        this.name = name;
    }


    // ----------------------------------------------------- Instance Variables

    
The Context this RequestDispatcher is associated with.

/**
     * The Context this RequestDispatcher is associated with.
     */
    private final Context context;


    
The servlet name for a named dispatcher.

/**
     * The servlet name for a named dispatcher.
     */
    private final String name;


    
The extra path information for this RequestDispatcher.

/**
     * The extra path information for this RequestDispatcher.
     */
    private final String pathInfo;


    
The query string parameters for this RequestDispatcher.

/**
     * The query string parameters for this RequestDispatcher.
     */
    private final String queryString;


    
The request URI for this RequestDispatcher.

/**
     * The request URI for this RequestDispatcher.
     */
    private final String requestURI;


    
The servlet path for this RequestDispatcher.

/**
     * The servlet path for this RequestDispatcher.
     */
    private final String servletPath;


    
The mapping for this RequestDispatcher.

/**
     * The mapping for this RequestDispatcher.
     */
    private final HttpServletMapping mapping;


    
The StringManager for this package.

/**
     * The StringManager for this package.
     */
    private static final StringManager sm = StringManager.getManager(Constants.Package);


    
The Wrapper associated with the resource that will be forwarded to
or included.

/**
     * The Wrapper associated with the resource that will be forwarded to
     * or included.
     */
    private final Wrapper wrapper;


    // --------------------------------------------------------- Public Methods


    
Forward this request and response to another resource for processing.
Any runtime exception, IOException, or ServletException thrown by the
called servlet will be propagated to the caller.

Params:
  • request – The servlet request to be forwarded
  • response – The servlet response to be forwarded
Throws:
/**
     * Forward this request and response to another resource for processing.
     * Any runtime exception, IOException, or ServletException thrown by the
     * called servlet will be propagated to the caller.
     *
     * @param request The servlet request to be forwarded
     * @param response The servlet response to be forwarded
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet exception occurs
     */
    @Override
    public void forward(ServletRequest request, ServletResponse response)
        throws ServletException, IOException
    {
        if (Globals.IS_SECURITY_ENABLED) {
            try {
                PrivilegedForward dp = new PrivilegedForward(request,response);
                AccessController.doPrivileged(dp);
            } catch (PrivilegedActionException pe) {
                Exception e = pe.getException();
                if (e instanceof ServletException)
                    throw (ServletException) e;
                throw (IOException) e;
            }
        } else {
            doForward(request,response);
        }
    }

    private void doForward(ServletRequest request, ServletResponse response)
        throws ServletException, IOException
    {

        // Reset any output that has been buffered, but keep headers/cookies
        if (response.isCommitted()) {
            throw new IllegalStateException
                (sm.getString("applicationDispatcher.forward.ise"));
        }
        try {
            response.resetBuffer();
        } catch (IllegalStateException e) {
            throw e;
        }

        // Set up to handle the specified request and response
        State state = new State(request, response, false);

        if (context.getDispatcherWrapsSameObject()) {
            // Check SRV.8.2 / SRV.14.2.5.1 compliance
            checkSameObjects(request, response);
        }

        wrapResponse(state);
        // Handle an HTTP named dispatcher forward
        if ((servletPath == null) && (pathInfo == null)) {

            ApplicationHttpRequest wrequest =
                (ApplicationHttpRequest) wrapRequest(state);
            HttpServletRequest hrequest = state.hrequest;
            wrequest.setRequestURI(hrequest.getRequestURI());
            wrequest.setContextPath(hrequest.getContextPath());
            wrequest.setServletPath(hrequest.getServletPath());
            wrequest.setPathInfo(hrequest.getPathInfo());
            wrequest.setQueryString(hrequest.getQueryString());

            processRequest(request,response,state);
        }

        // Handle an HTTP path-based forward
        else {

            ApplicationHttpRequest wrequest = (ApplicationHttpRequest) wrapRequest(state);
            HttpServletRequest hrequest = state.hrequest;
            if (hrequest.getAttribute(RequestDispatcher.FORWARD_REQUEST_URI) == null) {
                wrequest.setAttribute(RequestDispatcher.FORWARD_REQUEST_URI,
                                      hrequest.getRequestURI());
                wrequest.setAttribute(RequestDispatcher.FORWARD_CONTEXT_PATH,
                                      hrequest.getContextPath());
                wrequest.setAttribute(RequestDispatcher.FORWARD_SERVLET_PATH,
                                      hrequest.getServletPath());
                wrequest.setAttribute(RequestDispatcher.FORWARD_PATH_INFO,
                                      hrequest.getPathInfo());
                wrequest.setAttribute(RequestDispatcher.FORWARD_QUERY_STRING,
                                      hrequest.getQueryString());
                wrequest.setAttribute(RequestDispatcher.FORWARD_MAPPING, hrequest.getHttpServletMapping());
            }

            wrequest.setContextPath(context.getEncodedPath());
            wrequest.setRequestURI(requestURI);
            wrequest.setServletPath(servletPath);
            wrequest.setPathInfo(pathInfo);
            if (queryString != null) {
                wrequest.setQueryString(queryString);
                wrequest.setQueryParams(queryString);
            }
            wrequest.setMapping(mapping);

            processRequest(request,response,state);
        }

        if (request.isAsyncStarted()) {
            // An async request was started during the forward, don't close the
            // response as it may be written to during the async handling
            return;
        }

        // This is not a real close in order to support error processing
        if (wrapper.getLogger().isDebugEnabled() )
            wrapper.getLogger().debug(" Disabling the response for further output");

        if  (response instanceof ResponseFacade) {
            ((ResponseFacade) response).finish();
        } else {
            // Servlet SRV.6.2.2. The Request/Response may have been wrapped
            // and may no longer be instance of RequestFacade
            if (wrapper.getLogger().isDebugEnabled()){
                wrapper.getLogger().debug( " The Response is vehiculed using a wrapper: "
                           + response.getClass().getName() );
            }

            // Close anyway
            try {
                PrintWriter writer = response.getWriter();
                writer.close();
            } catch (IllegalStateException e) {
                try {
                    ServletOutputStream stream = response.getOutputStream();
                    stream.close();
                } catch (IllegalStateException f) {
                    // Ignore
                } catch (IOException f) {
                    // Ignore
                }
            } catch (IOException e) {
                // Ignore
            }
        }

    }


    
Prepare the request based on the filter configuration.

Params:
  • request – The servlet request we are processing
  • response – The servlet response we are creating
  • state – The RD state
Throws:
/**
     * Prepare the request based on the filter configuration.
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param state The RD state
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    private void processRequest(ServletRequest request,
                                ServletResponse response,
                                State state)
        throws IOException, ServletException {

        DispatcherType disInt = (DispatcherType) request.getAttribute(Globals.DISPATCHER_TYPE_ATTR);
        if (disInt != null) {
            boolean doInvoke = true;

            if (context.getFireRequestListenersOnForwards() &&
                    !context.fireRequestInitEvent(request)) {
                doInvoke = false;
            }

            if (doInvoke) {
                if (disInt != DispatcherType.ERROR) {
                    state.outerRequest.setAttribute(
                            Globals.DISPATCHER_REQUEST_PATH_ATTR,
                            getCombinedPath());
                    state.outerRequest.setAttribute(
                            Globals.DISPATCHER_TYPE_ATTR,
                            DispatcherType.FORWARD);
                    invoke(state.outerRequest, response, state);
                } else {
                    invoke(state.outerRequest, response, state);
                }

                if (context.getFireRequestListenersOnForwards()) {
                    context.fireRequestDestroyEvent(request);
                }
            }
        }
    }


    
Combine the servletPath and the pathInfo. If pathInfo is
null it is ignored. If servletPath is null then
null is returned.

Returns:The combined path with pathInfo appended to servletInfo
/**
     * Combine the servletPath and the pathInfo. If pathInfo is
     * <code>null</code> it is ignored. If servletPath is <code>null</code> then
     * <code>null</code> is returned.
     * @return The combined path with pathInfo appended to servletInfo
     */
    private String getCombinedPath() {
        if (servletPath == null) {
            return null;
        }
        if (pathInfo == null) {
            return servletPath;
        }
        return servletPath + pathInfo;
    }


    
Include the response from another resource in the current response.
Any runtime exception, IOException, or ServletException thrown by the
called servlet will be propagated to the caller.

Params:
  • request – The servlet request that is including this one
  • response – The servlet response to be appended to
Throws:
/**
     * Include the response from another resource in the current response.
     * Any runtime exception, IOException, or ServletException thrown by the
     * called servlet will be propagated to the caller.
     *
     * @param request The servlet request that is including this one
     * @param response The servlet response to be appended to
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet exception occurs
     */
    @Override
    public void include(ServletRequest request, ServletResponse response)
        throws ServletException, IOException
    {
        if (Globals.IS_SECURITY_ENABLED) {
            try {
                PrivilegedInclude dp = new PrivilegedInclude(request,response);
                AccessController.doPrivileged(dp);
            } catch (PrivilegedActionException pe) {
                Exception e = pe.getException();

                if (e instanceof ServletException)
                    throw (ServletException) e;
                throw (IOException) e;
            }
        } else {
            doInclude(request, response);
        }
    }

    private void doInclude(ServletRequest request, ServletResponse response)
            throws ServletException, IOException {

        // Set up to handle the specified request and response
        State state = new State(request, response, true);

        if (context.getDispatcherWrapsSameObject()) {
            // Check SRV.8.2 / SRV.14.2.5.1 compliance
            checkSameObjects(request, response);
        }

        // Create a wrapped response to use for this request
        wrapResponse(state);

        // Handle an HTTP named dispatcher include
        if (name != null) {

            ApplicationHttpRequest wrequest =
                (ApplicationHttpRequest) wrapRequest(state);
            wrequest.setAttribute(Globals.NAMED_DISPATCHER_ATTR, name);
            if (servletPath != null)
                wrequest.setServletPath(servletPath);
            wrequest.setAttribute(Globals.DISPATCHER_TYPE_ATTR,
                    DispatcherType.INCLUDE);
            wrequest.setAttribute(Globals.DISPATCHER_REQUEST_PATH_ATTR,
                    getCombinedPath());
            invoke(state.outerRequest, state.outerResponse, state);
        }

        // Handle an HTTP path based include
        else {

            ApplicationHttpRequest wrequest =
                (ApplicationHttpRequest) wrapRequest(state);
            String contextPath = context.getPath();
            if (requestURI != null)
                wrequest.setAttribute(RequestDispatcher.INCLUDE_REQUEST_URI,
                                      requestURI);
            if (contextPath != null)
                wrequest.setAttribute(RequestDispatcher.INCLUDE_CONTEXT_PATH,
                                      contextPath);
            if (servletPath != null)
                wrequest.setAttribute(RequestDispatcher.INCLUDE_SERVLET_PATH,
                                      servletPath);
            if (pathInfo != null)
                wrequest.setAttribute(RequestDispatcher.INCLUDE_PATH_INFO,
                                      pathInfo);
            if (queryString != null) {
                wrequest.setAttribute(RequestDispatcher.INCLUDE_QUERY_STRING,
                                      queryString);
                wrequest.setQueryParams(queryString);
            }
            if (mapping != null) {
                wrequest.setAttribute(RequestDispatcher.INCLUDE_MAPPING, mapping);
            }

            wrequest.setAttribute(Globals.DISPATCHER_TYPE_ATTR,
                    DispatcherType.INCLUDE);
            wrequest.setAttribute(Globals.DISPATCHER_REQUEST_PATH_ATTR,
                    getCombinedPath());
            invoke(state.outerRequest, state.outerResponse, state);
        }

    }


    @Override
    public void dispatch(ServletRequest request, ServletResponse response)
            throws ServletException, IOException {
        if (Globals.IS_SECURITY_ENABLED) {
            try {
                PrivilegedDispatch dp = new PrivilegedDispatch(request,response);
                AccessController.doPrivileged(dp);
            } catch (PrivilegedActionException pe) {
                Exception e = pe.getException();

                if (e instanceof ServletException)
                    throw (ServletException) e;
                throw (IOException) e;
            }
        } else {
            doDispatch(request, response);
        }
    }

    private void doDispatch(ServletRequest request, ServletResponse response)
            throws ServletException, IOException {

        // Set up to handle the specified request and response
        State state = new State(request, response, false);

        // Create a wrapped response to use for this request
        wrapResponse(state);

        ApplicationHttpRequest wrequest = (ApplicationHttpRequest) wrapRequest(state);
        HttpServletRequest hrequest = state.hrequest;

        wrequest.setAttribute(Globals.DISPATCHER_TYPE_ATTR, DispatcherType.ASYNC);
        wrequest.setAttribute(Globals.DISPATCHER_REQUEST_PATH_ATTR, getCombinedPath());
        wrequest.setAttribute(AsyncContext.ASYNC_MAPPING, hrequest.getHttpServletMapping());

        wrequest.setContextPath(context.getEncodedPath());
        wrequest.setRequestURI(requestURI);
        wrequest.setServletPath(servletPath);
        wrequest.setPathInfo(pathInfo);
        if (queryString != null) {
            wrequest.setQueryString(queryString);
            wrequest.setQueryParams(queryString);
        }
        if (!Globals.STRICT_SERVLET_COMPLIANCE) {
            wrequest.setMapping(mapping);
        }

        invoke(state.outerRequest, state.outerResponse, state);
    }


    // -------------------------------------------------------- Private Methods


    
Ask the resource represented by this RequestDispatcher to process
the associated request, and create (or append to) the associated
response.


IMPLEMENTATION NOTE: This implementation assumes
that no filters are applied to a forwarded or included resource,
because they were already done for the original request.

Params:
  • request – The servlet request we are processing
  • response – The servlet response we are creating
Throws:
/**
     * Ask the resource represented by this RequestDispatcher to process
     * the associated request, and create (or append to) the associated
     * response.
     * <p>
     * <strong>IMPLEMENTATION NOTE</strong>: This implementation assumes
     * that no filters are applied to a forwarded or included resource,
     * because they were already done for the original request.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    private void invoke(ServletRequest request, ServletResponse response,
            State state) throws IOException, ServletException {

        // Checking to see if the context classloader is the current context
        // classloader. If it's not, we're saving it, and setting the context
        // classloader to the Context classloader
        ClassLoader oldCCL = context.bind(false, null);

        // Initialize local variables we may need
        HttpServletResponse hresponse = state.hresponse;
        Servlet servlet = null;
        IOException ioException = null;
        ServletException servletException = null;
        RuntimeException runtimeException = null;
        boolean unavailable = false;

        // Check for the servlet being marked unavailable
        if (wrapper.isUnavailable()) {
            wrapper.getLogger().warn(
                    sm.getString("applicationDispatcher.isUnavailable",
                    wrapper.getName()));
            long available = wrapper.getAvailable();
            if ((available > 0L) && (available < Long.MAX_VALUE))
                hresponse.setDateHeader("Retry-After", available);
            hresponse.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE, sm
                    .getString("applicationDispatcher.isUnavailable", wrapper
                            .getName()));
            unavailable = true;
        }

        // Allocate a servlet instance to process this request
        try {
            if (!unavailable) {
                servlet = wrapper.allocate();
            }
        } catch (ServletException e) {
            wrapper.getLogger().error(sm.getString("applicationDispatcher.allocateException",
                             wrapper.getName()), StandardWrapper.getRootCause(e));
            servletException = e;
        } catch (Throwable e) {
            ExceptionUtils.handleThrowable(e);
            wrapper.getLogger().error(sm.getString("applicationDispatcher.allocateException",
                             wrapper.getName()), e);
            servletException = new ServletException
                (sm.getString("applicationDispatcher.allocateException",
                              wrapper.getName()), e);
            servlet = null;
        }

        // Get the FilterChain Here
        ApplicationFilterChain filterChain =
                ApplicationFilterFactory.createFilterChain(request, wrapper, servlet);

        // Call the service() method for the allocated servlet instance
        try {
            // for includes/forwards
            if ((servlet != null) && (filterChain != null)) {
               filterChain.doFilter(request, response);
             }
            // Servlet Service Method is called by the FilterChain
        } catch (ClientAbortException e) {
            ioException = e;
        } catch (IOException e) {
            wrapper.getLogger().error(sm.getString("applicationDispatcher.serviceException",
                             wrapper.getName()), e);
            ioException = e;
        } catch (UnavailableException e) {
            wrapper.getLogger().error(sm.getString("applicationDispatcher.serviceException",
                             wrapper.getName()), e);
            servletException = e;
            wrapper.unavailable(e);
        } catch (ServletException e) {
            Throwable rootCause = StandardWrapper.getRootCause(e);
            if (!(rootCause instanceof ClientAbortException)) {
                wrapper.getLogger().error(sm.getString("applicationDispatcher.serviceException",
                        wrapper.getName()), rootCause);
            }
            servletException = e;
        } catch (RuntimeException e) {
            wrapper.getLogger().error(sm.getString("applicationDispatcher.serviceException",
                             wrapper.getName()), e);
            runtimeException = e;
        }

        // Release the filter chain (if any) for this request
        if (filterChain != null) {
            filterChain.release();
        }

        // Deallocate the allocated servlet instance
        try {
            if (servlet != null) {
                wrapper.deallocate(servlet);
            }
        } catch (ServletException e) {
            wrapper.getLogger().error(sm.getString("applicationDispatcher.deallocateException",
                             wrapper.getName()), e);
            servletException = e;
        } catch (Throwable e) {
            ExceptionUtils.handleThrowable(e);
            wrapper.getLogger().error(sm.getString("applicationDispatcher.deallocateException",
                             wrapper.getName()), e);
            servletException = new ServletException
                (sm.getString("applicationDispatcher.deallocateException",
                              wrapper.getName()), e);
        }

        // Reset the old context class loader
        context.unbind(false, oldCCL);

        // Unwrap request/response if needed
        // See Bugzilla 30949
        unwrapRequest(state);
        unwrapResponse(state);
        // Recycle request if necessary (also BZ 30949)
        recycleRequestWrapper(state);

        // Rethrow an exception if one was thrown by the invoked servlet
        if (ioException != null)
            throw ioException;
        if (servletException != null)
            throw servletException;
        if (runtimeException != null)
            throw runtimeException;

    }


    
Unwrap the request if we have wrapped it.

/**
     * Unwrap the request if we have wrapped it.
     */
    private void unwrapRequest(State state) {

        if (state.wrapRequest == null)
            return;

        if (state.outerRequest.isAsyncStarted()) {
            if (!state.outerRequest.getAsyncContext().hasOriginalRequestAndResponse()) {
                return;
            }
        }

        ServletRequest previous = null;
        ServletRequest current = state.outerRequest;
        while (current != null) {

            // If we run into the container request we are done
            if ((current instanceof Request)
                || (current instanceof RequestFacade))
                break;

            // Remove the current request if it is our wrapper
            if (current == state.wrapRequest) {
                ServletRequest next =
                  ((ServletRequestWrapper) current).getRequest();
                if (previous == null)
                    state.outerRequest = next;
                else
                    ((ServletRequestWrapper) previous).setRequest(next);
                break;
            }

            // Advance to the next request in the chain
            previous = current;
            current = ((ServletRequestWrapper) current).getRequest();

        }

    }

    
Unwrap the response if we have wrapped it.

/**
     * Unwrap the response if we have wrapped it.
     */
    private void unwrapResponse(State state) {

        if (state.wrapResponse == null)
            return;

        if (state.outerRequest.isAsyncStarted()) {
            if (!state.outerRequest.getAsyncContext().hasOriginalRequestAndResponse()) {
                return;
            }
        }

        ServletResponse previous = null;
        ServletResponse current = state.outerResponse;
        while (current != null) {

            // If we run into the container response we are done
            if ((current instanceof Response)
                || (current instanceof ResponseFacade))
                break;

            // Remove the current response if it is our wrapper
            if (current == state.wrapResponse) {
                ServletResponse next =
                  ((ServletResponseWrapper) current).getResponse();
                if (previous == null)
                    state.outerResponse = next;
                else
                    ((ServletResponseWrapper) previous).setResponse(next);
                break;
            }

            // Advance to the next response in the chain
            previous = current;
            current = ((ServletResponseWrapper) current).getResponse();

        }

    }


    
Create and return a request wrapper that has been inserted in the
appropriate spot in the request chain.

/**
     * Create and return a request wrapper that has been inserted in the
     * appropriate spot in the request chain.
     */
    private ServletRequest wrapRequest(State state) {

        // Locate the request we should insert in front of
        ServletRequest previous = null;
        ServletRequest current = state.outerRequest;
        while (current != null) {
            if(state.hrequest == null && (current instanceof HttpServletRequest))
                state.hrequest = (HttpServletRequest)current;
            if (!(current instanceof ServletRequestWrapper))
                break;
            if (current instanceof ApplicationHttpRequest)
                break;
            if (current instanceof ApplicationRequest)
                break;
            previous = current;
            current = ((ServletRequestWrapper) current).getRequest();
        }

        // Instantiate a new wrapper at this point and insert it in the chain
        ServletRequest wrapper = null;
        if ((current instanceof ApplicationHttpRequest) ||
            (current instanceof Request) ||
            (current instanceof HttpServletRequest)) {
            // Compute a crossContext flag
            HttpServletRequest hcurrent = (HttpServletRequest) current;
            boolean crossContext = false;
            if ((state.outerRequest instanceof ApplicationHttpRequest) ||
                (state.outerRequest instanceof Request) ||
                (state.outerRequest instanceof HttpServletRequest)) {
                HttpServletRequest houterRequest =
                    (HttpServletRequest) state.outerRequest;
                Object contextPath = houterRequest.getAttribute(
                        RequestDispatcher.INCLUDE_CONTEXT_PATH);
                if (contextPath == null) {
                    // Forward
                    contextPath = houterRequest.getContextPath();
                }
                crossContext = !(context.getPath().equals(contextPath));
            }
            wrapper = new ApplicationHttpRequest
                (hcurrent, context, crossContext);
        } else {
            wrapper = new ApplicationRequest(current);
        }
        if (previous == null)
            state.outerRequest = wrapper;
        else
            ((ServletRequestWrapper) previous).setRequest(wrapper);
        state.wrapRequest = wrapper;
        return wrapper;

    }


    
Create and return a response wrapper that has been inserted in the
appropriate spot in the response chain.

/**
     * Create and return a response wrapper that has been inserted in the
     * appropriate spot in the response chain.
     */
    private ServletResponse wrapResponse(State state) {

        // Locate the response we should insert in front of
        ServletResponse previous = null;
        ServletResponse current = state.outerResponse;
        while (current != null) {
            if(state.hresponse == null && (current instanceof HttpServletResponse)) {
                state.hresponse = (HttpServletResponse)current;
                if(!state.including) // Forward only needs hresponse
                    return null;
            }
            if (!(current instanceof ServletResponseWrapper))
                break;
            if (current instanceof ApplicationHttpResponse)
                break;
            if (current instanceof ApplicationResponse)
                break;
            previous = current;
            current = ((ServletResponseWrapper) current).getResponse();
        }

        // Instantiate a new wrapper at this point and insert it in the chain
        ServletResponse wrapper = null;
        if ((current instanceof ApplicationHttpResponse) ||
            (current instanceof Response) ||
            (current instanceof HttpServletResponse))
            wrapper =
                new ApplicationHttpResponse((HttpServletResponse) current,
                        state.including);
        else
            wrapper = new ApplicationResponse(current, state.including);
        if (previous == null)
            state.outerResponse = wrapper;
        else
            ((ServletResponseWrapper) previous).setResponse(wrapper);
        state.wrapResponse = wrapper;
        return wrapper;

    }

    private void checkSameObjects(ServletRequest appRequest,
            ServletResponse appResponse) throws ServletException {
        ServletRequest originalRequest =
            ApplicationFilterChain.getLastServicedRequest();
        ServletResponse originalResponse =
            ApplicationFilterChain.getLastServicedResponse();

        // Some forwards, eg from valves will not set original values
        if (originalRequest == null || originalResponse == null) {
            return;
        }

        boolean same = false;
        ServletRequest dispatchedRequest = appRequest;

        //find the request that was passed into the service method
        while (originalRequest instanceof ServletRequestWrapper &&
                ((ServletRequestWrapper) originalRequest).getRequest()!=null ) {
            originalRequest =
                ((ServletRequestWrapper) originalRequest).getRequest();
        }
        //compare with the dispatched request
        while (!same) {
            if (originalRequest.equals(dispatchedRequest)) {
                same = true;
            }
            if (!same && dispatchedRequest instanceof ServletRequestWrapper) {
                dispatchedRequest =
                    ((ServletRequestWrapper) dispatchedRequest).getRequest();
            } else {
                break;
            }
        }
        if (!same) {
            throw new ServletException(sm.getString(
                    "applicationDispatcher.specViolation.request"));
        }

        same = false;
        ServletResponse dispatchedResponse = appResponse;

        //find the response that was passed into the service method
        while (originalResponse instanceof ServletResponseWrapper &&
                ((ServletResponseWrapper) originalResponse).getResponse() !=
                    null ) {
            originalResponse =
                ((ServletResponseWrapper) originalResponse).getResponse();
        }
        //compare with the dispatched response
        while (!same) {
            if (originalResponse.equals(dispatchedResponse)) {
                same = true;
            }

            if (!same && dispatchedResponse instanceof ServletResponseWrapper) {
                dispatchedResponse =
                    ((ServletResponseWrapper) dispatchedResponse).getResponse();
            } else {
                break;
            }
        }

        if (!same) {
            throw new ServletException(sm.getString(
                    "applicationDispatcher.specViolation.response"));
        }
    }

    private void recycleRequestWrapper(State state) {
        if (state.wrapRequest instanceof ApplicationHttpRequest) {
            ((ApplicationHttpRequest) state.wrapRequest).recycle();
        }
    }
}