Java tutorial
/* * 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.cocoon.servlet; import java.io.IOException; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.time.StopWatch; import org.springframework.beans.factory.BeanFactory; import org.springframework.web.context.support.WebApplicationContextUtils; import org.apache.cocoon.ConnectionResetException; import org.apache.cocoon.Constants; import org.apache.cocoon.Processor; import org.apache.cocoon.RequestListener; import org.apache.cocoon.ResourceNotFoundException; import org.apache.cocoon.configuration.Settings; import org.apache.cocoon.core.container.spring.logger.LoggerUtils; import org.apache.cocoon.environment.Context; import org.apache.cocoon.environment.Environment; import org.apache.cocoon.environment.http.HttpContext; import org.apache.cocoon.environment.http.HttpEnvironment; import org.apache.cocoon.environment.internal.EnvironmentHelper; import org.apache.cocoon.util.AbstractLogEnabled; /** * This is the entry point for Cocoon execution as an HTTP Servlet. * * @version $Id: RequestProcessor.java 606165 2007-12-21 11:39:45Z vgritsenko $ */ public class RequestProcessor extends AbstractLogEnabled { // Processing time message protected static final String PROCESSED_BY = "Processed by Apache Cocoon in "; // Used by "show-time" static final float SECOND = 1000; static final float MINUTE = 60 * SECOND; static final float HOUR = 60 * MINUTE; /** The servlet context. */ protected final ServletContext servletContext; /** Cocoon environment context. */ protected final Context environmentContext; /** Configured servlet container encoding. Defaults to ISO-8859-1. */ protected final String containerEncoding; /** Root Cocoon Bean Factory. */ protected final BeanFactory cocoonBeanFactory; /** The root settings. */ protected final Settings settings; /** The special servlet settings. */ protected final ServletSettings servletSettings; /** The processor. */ protected Processor processor; /** * An optional component that is called before and after processing all * requests. */ protected RequestListener requestListener; public RequestProcessor(ServletContext servletContext) { this.servletContext = servletContext; this.cocoonBeanFactory = WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext); this.settings = (Settings) this.cocoonBeanFactory.getBean(Settings.ROLE); this.servletSettings = new ServletSettings(this.settings); final String encoding = this.settings.getContainerEncoding(); if (encoding == null) { this.containerEncoding = "ISO-8859-1"; } else { this.containerEncoding = encoding; } // Obtain access logger String category = servletContext.getInitParameter("org.apache.cocoon.servlet.logger.access"); if (category == null || category.length() == 0) { category = "access"; } setLogger(LoggerUtils.getChildLogger(this.cocoonBeanFactory, category)); this.processor = getProcessor(); this.environmentContext = new HttpContext(this.servletContext); // get the optional request listener if (this.cocoonBeanFactory.containsBean(RequestListener.ROLE)) { this.requestListener = (RequestListener) this.cocoonBeanFactory.getBean(RequestListener.ROLE); } } protected Processor getProcessor() { return (Processor) this.cocoonBeanFactory.getBean(Processor.ROLE); } protected boolean rethrowExceptions() { return false; } /** * Process the specified <code>HttpServletRequest</code> producing output * on the specified <code>HttpServletResponse</code>. */ public void service(HttpServletRequest request, HttpServletResponse res) throws ServletException, IOException { // used for timing the processing StopWatch stopWatch = new StopWatch(); stopWatch.start(); // add the cocoon version header stamp if (this.servletSettings.isShowVersion()) { res.addHeader("X-Cocoon-Version", Constants.VERSION); } // We got it... Process the request final String uri = getURI(request, res); if (uri == null) { // a redirect occured, so we are finished return; } Environment env; try { // Pass uri into environment without URLDecoding, as it is already decoded. env = getEnvironment(uri, request, res); } catch (Exception e) { if (getLogger().isErrorEnabled()) { getLogger().error("Problem with Cocoon servlet", e); } if (rethrowExceptions()) { throw new ServletException(e); } RequestUtil.manageException(request, res, null, uri, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Problem in creating the Environment", null, null, e, this.servletSettings, getLogger(), this); return; } String contentType = null; try { if (process(env)) { contentType = env.getContentType(); } else { // We reach this when there is nothing in the processing chain that matches // the request. For example, no matcher matches. getLogger().fatal("The Cocoon engine failed to process the request."); if (rethrowExceptions()) { throw new ServletException("The Cocoon engine failed to process the request."); } RequestUtil.manageException(request, res, env, uri, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Request Processing Failed", "Cocoon engine failed in processing the request", "The processing engine failed to process the request. This could be due to lack of matching or bugs in the pipeline engine.", null, this.servletSettings, getLogger(), this); return; } } catch (ResourceNotFoundException e) { if (getLogger().isDebugEnabled()) { getLogger().warn(e.getMessage(), e); } else if (getLogger().isWarnEnabled()) { getLogger().warn(e.getMessage()); } if (rethrowExceptions()) { throw new ServletException(e); } RequestUtil.manageException(request, res, env, uri, HttpServletResponse.SC_NOT_FOUND, "Resource Not Found", "Resource Not Found", "The requested resource \"" + request.getRequestURI() + "\" could not be found", e, this.servletSettings, getLogger(), this); return; } catch (ConnectionResetException e) { if (getLogger().isDebugEnabled()) { getLogger().debug(e.toString(), e); } else if (getLogger().isWarnEnabled()) { getLogger().warn(e.toString()); } } catch (IOException e) { // Tomcat5 wraps SocketException into ClientAbortException which extends IOException. if (getLogger().isDebugEnabled()) { getLogger().debug(e.toString(), e); } else if (getLogger().isWarnEnabled()) { getLogger().warn(e.toString()); } } catch (Exception e) { if (getLogger().isErrorEnabled()) { getLogger().error("Internal Cocoon Problem", e); } if (rethrowExceptions()) { throw new ServletException(e); } RequestUtil.manageException(request, res, env, uri, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Internal Server Error", null, null, e, this.servletSettings, getLogger(), this); return; } stopWatch.stop(); String timeString = null; if (getLogger().isInfoEnabled()) { timeString = processTime(stopWatch.getTime()); getLogger().info("'" + uri + "' " + timeString); } if (contentType != null && contentType.equals("text/html")) { String showTime = request.getParameter(Constants.SHOWTIME_PARAM); boolean show = this.servletSettings.isShowTime(); if (showTime != null) { show = !showTime.equalsIgnoreCase("no"); } if (show) { if (timeString == null) { timeString = processTime(stopWatch.getTime()); } boolean hide = this.servletSettings.isHideShowTime(); if (showTime != null) { hide = showTime.equalsIgnoreCase("hide"); } ServletOutputStream out = res.getOutputStream(); out.print((hide) ? "<!-- " : "<p>"); out.print(timeString); out.println((hide) ? " -->" : "</p>"); } } /* * Servlet Specification 2.2, 6.5 Closure of Response Object: * * A number of events can indicate that the servlet has provided all of the * content to satisfy the request and that the response object can be * considered to be closed. The events are: * o The termination of the service method of the servlet. * o When the amount of content specified in the setContentLength method * of the response has been written to the response. * o The sendError method is called. * o The sendRedirect method is called. * When a response is closed, all content in the response buffer, if any remains, * must be immediately flushed to the client. * * Due to the above, out.flush() and out.close() are not necessary, and sometimes * (if sendError or sendRedirect were used) request may be already closed. */ } protected String getURI(HttpServletRequest request, HttpServletResponse res) throws IOException { return RequestUtil.getCompleteUri(request, res); } /** * Create the environment for the request */ protected Environment getEnvironment(String uri, HttpServletRequest req, HttpServletResponse res) throws Exception { String formEncoding = req.getParameter("cocoon-form-encoding"); if (formEncoding == null) { formEncoding = this.settings.getFormEncoding(); } HttpEnvironment env; env = new HttpEnvironment(uri, req, res, this.servletContext, this.environmentContext, this.containerEncoding, formEncoding); return env; } private String processTime(long time) { StringBuffer out = new StringBuffer(PROCESSED_BY); if (time <= SECOND) { out.append(time); out.append(" milliseconds."); } else if (time <= MINUTE) { out.append(time / SECOND); out.append(" seconds."); } else if (time <= HOUR) { out.append(time / MINUTE); out.append(" minutes."); } else { out.append(time / HOUR); out.append(" hours."); } return out.toString(); } /** * @see org.apache.cocoon.Processor#process(org.apache.cocoon.environment.Environment) */ protected boolean process(Environment environment) throws Exception { environment.startingProcessing(); final int environmentDepth = EnvironmentHelper.markEnvironment(); EnvironmentHelper.enterProcessor(this.processor, environment); try { boolean result; if (this.requestListener != null) { try { requestListener.onRequestStart(environment); } catch (Exception e) { getLogger().error("Error encountered monitoring request start", e); } } result = this.processor.process(environment); if (this.requestListener != null) { try { requestListener.onRequestEnd(environment); } catch (Exception e) { getLogger().error("Error encountered monitoring request end", e); } } // commit response on success environment.commitResponse(); return result; } catch (Exception any) { if (this.requestListener != null) { try { requestListener.onRequestException(environment, any); } catch (Exception e) { getLogger().error("Error encountered monitoring request exception", e); } } // reset response on error environment.tryResetResponse(); throw any; } finally { EnvironmentHelper.leaveProcessor(); environment.finishingProcessing(); EnvironmentHelper.checkEnvironment(environmentDepth); } } }