applicationfilterfactory.java

业界著名的tomcat服务器的最新6.0的源代码。

/*
 * 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 javax.servlet.Servlet;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;

import org.apache.catalina.CometFilter;
import org.apache.catalina.Globals;
import org.apache.catalina.Wrapper;
import org.apache.catalina.connector.Request;
import org.apache.catalina.deploy.FilterMap;

/**
 * Factory for the creation and caching of Filters and creationg 
 * of Filter Chains.
 *
 * @author Greg Murray
 * @author Remy Maucherat
 * @version $Revision: 1.0
 */

public final class ApplicationFilterFactory {


    // -------------------------------------------------------------- Constants


    public static final int ERROR = 1;
    public static final Integer ERROR_INTEGER = new Integer(ERROR);
    public static final int FORWARD = 2;
    public static final Integer FORWARD_INTEGER = new Integer(FORWARD);
    public static final int INCLUDE = 4;
    public static final Integer INCLUDE_INTEGER = new Integer(INCLUDE);
    public static final int REQUEST = 8;
    public static final Integer REQUEST_INTEGER = new Integer(REQUEST);

    public static final String DISPATCHER_TYPE_ATTR = 
        Globals.DISPATCHER_TYPE_ATTR;
    public static final String DISPATCHER_REQUEST_PATH_ATTR = 
        Globals.DISPATCHER_REQUEST_PATH_ATTR;

    private static ApplicationFilterFactory factory = null;;


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


    /*
     * Prevent instanciation outside of the getInstanceMethod().
     */
    private ApplicationFilterFactory() {
    }


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


    /**
     * Return the fqctory instance.
     */
    public static ApplicationFilterFactory getInstance() {
        if (factory == null) {
            factory = new ApplicationFilterFactory();
        }
        return factory;
    }


    /**
     * Construct and return a FilterChain implementation that will wrap the
     * execution of the specified servlet instance.  If we should not execute
     * a filter chain at all, return <code>null</code>.
     *
     * @param request The servlet request we are processing
     * @param servlet The servlet instance to be wrapped
     */
    public ApplicationFilterChain createFilterChain
        (ServletRequest request, Wrapper wrapper, Servlet servlet) {

        // get the dispatcher type
        int dispatcher = -1; 
        if (request.getAttribute(DISPATCHER_TYPE_ATTR) != null) {
            Integer dispatcherInt = 
                (Integer) request.getAttribute(DISPATCHER_TYPE_ATTR);
            dispatcher = dispatcherInt.intValue();
        }
        String requestPath = null;
        Object attribute = request.getAttribute(DISPATCHER_REQUEST_PATH_ATTR);
        
        if (attribute != null){
            requestPath = attribute.toString();
        }
        
        HttpServletRequest hreq = null;
        if (request instanceof HttpServletRequest) 
            hreq = (HttpServletRequest)request;
        // If there is no servlet to execute, return null
        if (servlet == null)
            return (null);

        boolean comet = false;
        
        // Create and initialize a filter chain object
        ApplicationFilterChain filterChain = null;
        if (!Globals.IS_SECURITY_ENABLED && (request instanceof Request)) {
            Request req = (Request) request;
            filterChain = (ApplicationFilterChain) req.getFilterChain();
            if (filterChain == null) {
                filterChain = new ApplicationFilterChain();
                req.setFilterChain(filterChain);
            }
            comet = req.isComet();
        } else {
            // Security: Do not recycle
            filterChain = new ApplicationFilterChain();
        }

        filterChain.setServlet(servlet);

        filterChain.setSupport
            (((StandardWrapper)wrapper).getInstanceSupport());

        // Acquire the filter mappings for this Context
        StandardContext context = (StandardContext) wrapper.getParent();
        FilterMap filterMaps[] = context.findFilterMaps();

        // If there are no filter mappings, we are done
        if ((filterMaps == null) || (filterMaps.length == 0))
            return (filterChain);

        // Acquire the information we will need to match filter mappings
        String servletName = wrapper.getName();

        // Add the relevant path-mapped filters to this filter chain
        for (int i = 0; i < filterMaps.length; i++) {
            if (!matchDispatcher(filterMaps[i] ,dispatcher)) {
                continue;
            }
            if (!matchFiltersURL(filterMaps[i], requestPath))
                continue;
            ApplicationFilterConfig filterConfig = (ApplicationFilterConfig)
                context.findFilterConfig(filterMaps[i].getFilterName());
            if (filterConfig == null) {
                ;       // FIXME - log configuration problem
                continue;
            }
            boolean isCometFilter = false;
            if (comet) {
                try {
                    isCometFilter = filterConfig.getFilter() instanceof CometFilter;
                } catch (Exception e) {
                    // Note: The try catch is there because getFilter has a lot of 
                    // declared exceptions. However, the filter is allocated much
                    // earlier
                }
                if (isCometFilter) {
                    filterChain.addFilter(filterConfig);
                }
            } else {
                filterChain.addFilter(filterConfig);
            }
        }

        // Add filters that match on servlet name second
        for (int i = 0; i < filterMaps.length; i++) {
            if (!matchDispatcher(filterMaps[i] ,dispatcher)) {
                continue;
            }
            if (!matchFiltersServlet(filterMaps[i], servletName))
                continue;
            ApplicationFilterConfig filterConfig = (ApplicationFilterConfig)
                context.findFilterConfig(filterMaps[i].getFilterName());
            if (filterConfig == null) {
                ;       // FIXME - log configuration problem
                continue;
            }
            boolean isCometFilter = false;
            if (comet) {
                try {
                    isCometFilter = filterConfig.getFilter() instanceof CometFilter;
                } catch (Exception e) {