--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/eclipse/jetty/continuation/ContinuationFilter.java	Wed Sep 07 21:15:48 2016 -0600
@@ -0,0 +1,174 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.continuation;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+
+
+/* ------------------------------------------------------------ */
+/**
+ * <p>ContinuationFilter must be applied to servlet paths that make use of
+ * the asynchronous features provided by {@link Continuation} APIs, but that
+ * are deployed in servlet containers that are neither Jetty (>= 7) nor a
+ * compliant Servlet 3.0 container.</p>
+ * <p>The following init parameters may be used to configure the filter (these are mostly for testing):</p>
+ * <dl>
+ * <dt>debug</dt><dd>Boolean controlling debug output</dd>
+ * <dt>jetty6</dt><dd>Boolean to force use of Jetty 6 continuations</dd>
+ * <dt>faux</dt><dd>Boolean to force use of faux continuations</dd>
+ * </dl>
+ * <p>If the servlet container is not Jetty (either 6 or 7) nor a Servlet 3
+ * container, then "faux" continuations will be used.</p>
+ * <p>Faux continuations will just put the thread that called {@link Continuation#suspend()}
+ * in wait, and will notify that thread when {@link Continuation#resume()} or
+ * {@link Continuation#complete()} is called.</p>
+ * <p>Faux continuations are not threadless continuations (they are "faux" - fake - for this reason)
+ * and as such they will scale less than proper continuations.</p>
+ */
+public class ContinuationFilter implements Filter
+{
+    static boolean _initialized;
+    static boolean __debug; // shared debug status
+    private boolean _faux;
+    private boolean _jetty6;
+    private boolean _filtered;
+    ServletContext _context;
+    private boolean _debug;
+
+    public void init(FilterConfig filterConfig) throws ServletException
+    {
+        boolean jetty_7_or_greater="org.eclipse.jetty.servlet".equals(filterConfig.getClass().getPackage().getName());
+        _context = filterConfig.getServletContext();
+
+        String param=filterConfig.getInitParameter("debug");
+        _debug=param!=null&&Boolean.parseBoolean(param);
+        if (_debug)
+            __debug=true;
+
+        param=filterConfig.getInitParameter("jetty6");
+        if (param==null)
+            param=filterConfig.getInitParameter("partial");
+        if (param!=null)
+            _jetty6=Boolean.parseBoolean(param);
+        else
+            _jetty6=ContinuationSupport.__jetty6 && !jetty_7_or_greater;
+
+        param=filterConfig.getInitParameter("faux");
+        if (param!=null)
+            _faux=Boolean.parseBoolean(param);
+        else
+            _faux=!(jetty_7_or_greater || _jetty6 || _context.getMajorVersion()>=3);
+
+        _filtered=_faux||_jetty6;
+        if (_debug)
+            _context.log("ContinuationFilter "+
+                    " jetty="+jetty_7_or_greater+
+                    " jetty6="+_jetty6+
+                    " faux="+_faux+
+                    " filtered="+_filtered+
+                    " servlet3="+ContinuationSupport.__servlet3);
+        _initialized=true;
+    }
+
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
+    {
+        if (_filtered)
+        {
+            Continuation c = (Continuation) request.getAttribute(Continuation.ATTRIBUTE);
+            FilteredContinuation fc;
+            if (_faux && (c==null || !(c instanceof FauxContinuation)))
+            {
+                fc = new FauxContinuation(request);
+                request.setAttribute(Continuation.ATTRIBUTE,fc);
+            }
+            else
+                fc=(FilteredContinuation)c;
+
+            boolean complete=false;
+            while (!complete)
+            {
+                try
+                {
+                    if (fc==null || (fc).enter(response))
+                        chain.doFilter(request,response);
+                }
+                catch (ContinuationThrowable e)
+                {
+                    debug("faux",e);
+                }
+                finally
+                {
+                    if (fc==null)
+                        fc = (FilteredContinuation) request.getAttribute(Continuation.ATTRIBUTE);
+
+                    complete=fc==null || (fc).exit();
+                }
+            }
+        }
+        else
+        {
+            try
+            {
+                chain.doFilter(request,response);
+            }
+            catch (ContinuationThrowable e)
+            {
+                debug("caught",e);
+            }
+        }
+    }
+
+    private void debug(String string)
+    {
+        if (_debug)
+        {
+            _context.log(string);
+        }
+    }
+
+    private void debug(String string, Throwable th)
+    {
+        if (_debug)
+        {
+            if (th instanceof ContinuationThrowable)
+                _context.log(string+":"+th);
+            else
+                _context.log(string,th);
+        }
+    }
+
+    public void destroy()
+    {
+    }
+
+    public interface FilteredContinuation extends Continuation
+    {
+        boolean enter(ServletResponse response);
+        boolean exit();
+    }
+}