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Tomcat example source code file (StandardWrapperValve.java)

This example Tomcat source code file (StandardWrapperValve.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

clientabortexception, context, http, io, ioexception, ioexception, management, request, response, response, retry-after, servlet, servletexception, servletexception, standardwrapper, string, string, throwable, throwable, unavailableexception

The Tomcat StandardWrapperValve.java source code

/*
 * 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 javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServletResponse;

import org.apache.catalina.CometEvent;
import org.apache.catalina.CometProcessor;
import org.apache.catalina.Context;
import org.apache.catalina.Globals;
import org.apache.catalina.connector.ClientAbortException;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.util.StringManager;
import org.apache.catalina.valves.ValveBase;
import org.apache.tomcat.util.buf.MessageBytes;
import org.apache.tomcat.util.log.SystemLogHandler;

/**
 * Valve that implements the default basic behavior for the
 * <code>StandardWrapper container implementation.
 *
 * @author Craig R. McClanahan
 * @version $Revision: 596489 $ $Date: 2007-11-20 00:38:40 +0100 (mar., 20 nov. 2007) $
 */

final class StandardWrapperValve
    extends ValveBase {

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


    // Some JMX statistics. This vavle is associated with a StandardWrapper.
    // We expose the StandardWrapper as JMX ( j2eeType=Servlet ). The fields
    // are here for performance.
    private volatile long processingTime;
    private volatile long maxTime;
    private volatile long minTime = Long.MAX_VALUE;
    private volatile int requestCount;
    private volatile int errorCount;


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


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


    /**
     * Invoke the servlet we are managing, respecting the rules regarding
     * servlet lifecycle and SingleThreadModel support.
     *
     * @param request Request to be processed
     * @param response Response to be produced
     * @param valveContext Valve context used to forward to the next Valve
     *
     * @exception IOException if an input/output error occurred
     * @exception ServletException if a servlet error occurred
     */
    public final void invoke(Request request, Response response)
        throws IOException, ServletException {

        // Initialize local variables we may need
        boolean unavailable = false;
        Throwable throwable = null;
        // This should be a Request attribute...
        long t1=System.currentTimeMillis();
        requestCount++;
        StandardWrapper wrapper = (StandardWrapper) getContainer();
        Servlet servlet = null;
        Context context = (Context) wrapper.getParent();
        
        // Check for the application being marked unavailable
        if (!context.getAvailable()) {
        	response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                           sm.getString("standardContext.isUnavailable"));
            unavailable = true;
        }

        // Check for the servlet being marked unavailable
        if (!unavailable && wrapper.isUnavailable()) {
            container.getLogger().info(sm.getString("standardWrapper.isUnavailable",
                    wrapper.getName()));
            long available = wrapper.getAvailable();
            if ((available > 0L) && (available < Long.MAX_VALUE)) {
                response.setDateHeader("Retry-After", available);
                response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                        sm.getString("standardWrapper.isUnavailable",
                                wrapper.getName()));
            } else if (available == Long.MAX_VALUE) {
                response.sendError(HttpServletResponse.SC_NOT_FOUND,
                        sm.getString("standardWrapper.notFound",
                                wrapper.getName()));
            }
            unavailable = true;
        }

        // Allocate a servlet instance to process this request
        try {
            if (!unavailable) {
                servlet = wrapper.allocate();
            }
        } catch (UnavailableException e) {
            container.getLogger().error(
                    sm.getString("standardWrapper.allocateException",
                            wrapper.getName()), e);
            long available = wrapper.getAvailable();
            if ((available > 0L) && (available < Long.MAX_VALUE)) {
            	response.setDateHeader("Retry-After", available);
            	response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                           sm.getString("standardWrapper.isUnavailable",
                                        wrapper.getName()));
            } else if (available == Long.MAX_VALUE) {
            	response.sendError(HttpServletResponse.SC_NOT_FOUND,
                           sm.getString("standardWrapper.notFound",
                                        wrapper.getName()));
            }
        } catch (ServletException e) {
            container.getLogger().error(sm.getString("standardWrapper.allocateException",
                             wrapper.getName()), StandardWrapper.getRootCause(e));
            throwable = e;
            exception(request, response, e);
            servlet = null;
        } catch (Throwable e) {
            container.getLogger().error(sm.getString("standardWrapper.allocateException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
            servlet = null;
        }

        // Identify if the request is Comet related now that the servlet has been allocated
        boolean comet = false;
        if (servlet instanceof CometProcessor 
                && request.getAttribute("org.apache.tomcat.comet.support") == Boolean.TRUE) {
            comet = true;
            request.setComet(true);
        }
        
        // Acknowledge the request
        try {
            response.sendAcknowledgement();
        } catch (IOException e) {
        	request.removeAttribute(Globals.JSP_FILE_ATTR);
            container.getLogger().warn(sm.getString("standardWrapper.acknowledgeException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
        } catch (Throwable e) {
            container.getLogger().error(sm.getString("standardWrapper.acknowledgeException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
            servlet = null;
        }
        MessageBytes requestPathMB = null;
        if (request != null) {
            requestPathMB = request.getRequestPathMB();
        }
        request.setAttribute
            (ApplicationFilterFactory.DISPATCHER_TYPE_ATTR,
             ApplicationFilterFactory.REQUEST_INTEGER);
        request.setAttribute
            (ApplicationFilterFactory.DISPATCHER_REQUEST_PATH_ATTR,
             requestPathMB);
        // Create the filter chain for this request
        ApplicationFilterFactory factory =
            ApplicationFilterFactory.getInstance();
        ApplicationFilterChain filterChain =
            factory.createFilterChain(request, wrapper, servlet);
        // Reset comet flag value after creating the filter chain
        request.setComet(false);

        // Call the filter chain for this request
        // NOTE: This also calls the servlet's service() method
        try {
            String jspFile = wrapper.getJspFile();
            if (jspFile != null)
            	request.setAttribute(Globals.JSP_FILE_ATTR, jspFile);
            else
            	request.removeAttribute(Globals.JSP_FILE_ATTR);
            if ((servlet != null) && (filterChain != null)) {
                // Swallow output if needed
                if (context.getSwallowOutput()) {
                    try {
                        SystemLogHandler.startCapture();
                        if (comet) {
                            filterChain.doFilterEvent(request.getEvent());
                            request.setComet(true);
                        } else {
                            filterChain.doFilter(request.getRequest(), 
                                    response.getResponse());
                        }
                    } finally {
                        String log = SystemLogHandler.stopCapture();
                        if (log != null && log.length() > 0) {
                            context.getLogger().info(log);
                        }
                    }
                } else {
                    if (comet) {
                        request.setComet(true);
                        filterChain.doFilterEvent(request.getEvent());
                    } else {
                        filterChain.doFilter
                            (request.getRequest(), response.getResponse());
                    }
                }

            }
            request.removeAttribute(Globals.JSP_FILE_ATTR);
        } catch (ClientAbortException e) {
        	request.removeAttribute(Globals.JSP_FILE_ATTR);
            throwable = e;
            exception(request, response, e);
        } catch (IOException e) {
        	request.removeAttribute(Globals.JSP_FILE_ATTR);
            container.getLogger().error(sm.getString("standardWrapper.serviceException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
        } catch (UnavailableException e) {
        	request.removeAttribute(Globals.JSP_FILE_ATTR);
            container.getLogger().error(sm.getString("standardWrapper.serviceException",
                             wrapper.getName()), e);
            //            throwable = e;
            //            exception(request, response, e);
            wrapper.unavailable(e);
            long available = wrapper.getAvailable();
            if ((available > 0L) && (available < Long.MAX_VALUE)) {
                response.setDateHeader("Retry-After", available);
                response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
                           sm.getString("standardWrapper.isUnavailable",
                                        wrapper.getName()));
            } else if (available == Long.MAX_VALUE) {
            	response.sendError(HttpServletResponse.SC_NOT_FOUND,
                            sm.getString("standardWrapper.notFound",
                                        wrapper.getName()));
            }
            // Do not save exception in 'throwable', because we
            // do not want to do exception(request, response, e) processing
        } catch (ServletException e) {
        	request.removeAttribute(Globals.JSP_FILE_ATTR);
            Throwable rootCause = StandardWrapper.getRootCause(e);
            if (!(rootCause instanceof ClientAbortException)) {
                container.getLogger().error(sm.getString("standardWrapper.serviceException",
                                 wrapper.getName()), rootCause);
            }
            throwable = e;
            exception(request, response, e);
        } catch (Throwable e) {
            request.removeAttribute(Globals.JSP_FILE_ATTR);
            container.getLogger().error(sm.getString("standardWrapper.serviceException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
        }

        // Release the filter chain (if any) for this request
        if (filterChain != null) {
            if (request.isComet()) {
                // If this is a Comet request, then the same chain will be used for the
                // processing of all subsequent events.
                filterChain.reuse();
            } else {
                filterChain.release();
            }
        }

        // Deallocate the allocated servlet instance
        try {
            if (servlet != null) {
                wrapper.deallocate(servlet);
            }
        } catch (Throwable e) {
            container.getLogger().error(sm.getString("standardWrapper.deallocateException",
                             wrapper.getName()), e);
            if (throwable == null) {
                throwable = e;
                exception(request, response, e);
            }
        }

        // If this servlet has been marked permanently unavailable,
        // unload it and release this instance
        try {
            if ((servlet != null) &&
                (wrapper.getAvailable() == Long.MAX_VALUE)) {
                wrapper.unload();
            }
        } catch (Throwable e) {
            container.getLogger().error(sm.getString("standardWrapper.unloadException",
                             wrapper.getName()), e);
            if (throwable == null) {
                throwable = e;
                exception(request, response, e);
            }
        }
        long t2=System.currentTimeMillis();

        long time=t2-t1;
        processingTime += time;
        if( time > maxTime) maxTime=time;
        if( time < minTime) minTime=time;

    }


    /**
     * Process a Comet event. The main differences here are to not use sendError
     * (the response is committed), to avoid creating a new filter chain
     * (which would work but be pointless), and a few very minor tweaks. 
     *
     * @param request The servlet request to be processed
     * @param response The servlet response to be created
     *
     * @exception IOException if an input/output error occurs, or is thrown
     *  by a subsequently invoked Valve, Filter, or Servlet
     * @exception ServletException if a servlet error occurs, or is thrown
     *  by a subsequently invoked Valve, Filter, or Servlet
     */
    public void event(Request request, Response response, CometEvent event)
        throws IOException, ServletException {
        
        // Initialize local variables we may need
        Throwable throwable = null;
        // This should be a Request attribute...
        long t1=System.currentTimeMillis();
        // FIXME: Add a flag to count the total amount of events processed ? requestCount++;
        StandardWrapper wrapper = (StandardWrapper) getContainer();
        Servlet servlet = null;
        Context context = (Context) wrapper.getParent();

        // Check for the application being marked unavailable
        boolean unavailable = !context.getAvailable() || wrapper.isUnavailable();
        
        // Allocate a servlet instance to process this request
        try {
            if (!unavailable) {
                servlet = wrapper.allocate();
            }
        } catch (UnavailableException e) {
            // The response is already committed, so it's not possible to do anything
        } catch (ServletException e) {
            container.getLogger().error(sm.getString("standardWrapper.allocateException",
                             wrapper.getName()), StandardWrapper.getRootCause(e));
            throwable = e;
            exception(request, response, e);
            servlet = null;
        } catch (Throwable e) {
            container.getLogger().error(sm.getString("standardWrapper.allocateException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
            servlet = null;
        }

        MessageBytes requestPathMB = null;
        if (request != null) {
            requestPathMB = request.getRequestPathMB();
        }
        request.setAttribute
            (ApplicationFilterFactory.DISPATCHER_TYPE_ATTR,
             ApplicationFilterFactory.REQUEST_INTEGER);
        request.setAttribute
            (ApplicationFilterFactory.DISPATCHER_REQUEST_PATH_ATTR,
             requestPathMB);
        // Get the current (unchanged) filter chain for this request
        ApplicationFilterChain filterChain = 
            (ApplicationFilterChain) request.getFilterChain();

        // Call the filter chain for this request
        // NOTE: This also calls the servlet's event() method
        try {
            String jspFile = wrapper.getJspFile();
            if (jspFile != null)
                request.setAttribute(Globals.JSP_FILE_ATTR, jspFile);
            else
                request.removeAttribute(Globals.JSP_FILE_ATTR);
            if ((servlet != null) && (filterChain != null)) {

                // Swallow output if needed
                if (context.getSwallowOutput()) {
                    try {
                        SystemLogHandler.startCapture();
                        filterChain.doFilterEvent(request.getEvent());
                    } finally {
                        String log = SystemLogHandler.stopCapture();
                        if (log != null && log.length() > 0) {
                            context.getLogger().info(log);
                        }
                    }
                } else {
                    filterChain.doFilterEvent(request.getEvent());
                }

            }
            request.removeAttribute(Globals.JSP_FILE_ATTR);
        } catch (ClientAbortException e) {
            request.removeAttribute(Globals.JSP_FILE_ATTR);
            throwable = e;
            exception(request, response, e);
        } catch (IOException e) {
            request.removeAttribute(Globals.JSP_FILE_ATTR);
            container.getLogger().error(sm.getString("standardWrapper.serviceException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
        } catch (UnavailableException e) {
            request.removeAttribute(Globals.JSP_FILE_ATTR);
            container.getLogger().error(sm.getString("standardWrapper.serviceException",
                             wrapper.getName()), e);
            // Do not save exception in 'throwable', because we
            // do not want to do exception(request, response, e) processing
        } catch (ServletException e) {
            request.removeAttribute(Globals.JSP_FILE_ATTR);
            Throwable rootCause = StandardWrapper.getRootCause(e);
            if (!(rootCause instanceof ClientAbortException)) {
                container.getLogger().error(sm.getString("standardWrapper.serviceException",
                                 wrapper.getName()), rootCause);
            }
            throwable = e;
            exception(request, response, e);
        } catch (Throwable e) {
            request.removeAttribute(Globals.JSP_FILE_ATTR);
            container.getLogger().error(sm.getString("standardWrapper.serviceException",
                             wrapper.getName()), e);
            throwable = e;
            exception(request, response, e);
        }

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

        // Deallocate the allocated servlet instance
        try {
            if (servlet != null) {
                wrapper.deallocate(servlet);
            }
        } catch (Throwable e) {
            container.getLogger().error(sm.getString("standardWrapper.deallocateException",
                             wrapper.getName()), e);
            if (throwable == null) {
                throwable = e;
                exception(request, response, e);
            }
        }

        // If this servlet has been marked permanently unavailable,
        // unload it and release this instance
        try {
            if ((servlet != null) &&
                (wrapper.getAvailable() == Long.MAX_VALUE)) {
                wrapper.unload();
            }
        } catch (Throwable e) {
            container.getLogger().error(sm.getString("standardWrapper.unloadException",
                             wrapper.getName()), e);
            if (throwable == null) {
                throwable = e;
                exception(request, response, e);
            }
        }

        long t2=System.currentTimeMillis();

        long time=t2-t1;
        processingTime += time;
        if( time > maxTime) maxTime=time;
        if( time < minTime) minTime=time;

    }


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


    /**
     * Handle the specified ServletException encountered while processing
     * the specified Request to produce the specified Response.  Any
     * exceptions that occur during generation of the exception report are
     * logged and swallowed.
     *
     * @param request The request being processed
     * @param response The response being generated
     * @param exception The exception that occurred (which possibly wraps
     *  a root cause exception
     */
    private void exception(Request request, Response response,
                           Throwable exception) {
    	request.setAttribute(Globals.EXCEPTION_ATTR, exception);
        response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);

    }

    public long getProcessingTime() {
        return processingTime;
    }

    public void setProcessingTime(long processingTime) {
        this.processingTime = processingTime;
    }

    public long getMaxTime() {
        return maxTime;
    }

    public void setMaxTime(long maxTime) {
        this.maxTime = maxTime;
    }

    public long getMinTime() {
        return minTime;
    }

    public void setMinTime(long minTime) {
        this.minTime = minTime;
    }

    public int getRequestCount() {
        return requestCount;
    }

    public void setRequestCount(int requestCount) {
        this.requestCount = requestCount;
    }

    public int getErrorCount() {
        return errorCount;
    }

    public void setErrorCount(int errorCount) {
        this.errorCount = errorCount;
    }

    // Don't register in JMX

    public ObjectName createObjectName(String domain, ObjectName parent)
            throws MalformedObjectNameException
    {
        return null;
    }
}

Other Tomcat examples (source code examples)

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