| // |
| // ======================================================================== |
| // 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(); |
| } |
| } |