Tomcat example source code file (ApplicationFilterFactory.java)

This example Tomcat source code file (ApplicationFilterFactory.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

applicationfilterchain, applicationfilterchain, applicationfilterconfig, applicationfilterfactory, applicationfilterfactory, forward, http, httpservletrequest, include, integer, integer, request, request, response, servlet, standardcontext, string, string

The Tomcat ApplicationFilterFactory.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 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.
     *
     * @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 (request instanceof Request) {
            Request req = (Request) request;
            comet = req.isComet();
            if (Globals.IS_SECURITY_ENABLED) {
                // Security: Do not recycle
                filterChain = new ApplicationFilterChain();
                if (comet) {
                    req.setFilterChain(filterChain);
                }
            } else {
                filterChain = (ApplicationFilterChain) req.getFilterChain();
                if (filterChain == null) {
                    filterChain = new ApplicationFilterChain();
                    req.setFilterChain(filterChain);
                }
            }
        } else {
            // Request dispatcher in use
            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) {
                    // 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);
            }
        }

        // Return the completed filter chain
        return (filterChain);

    }


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


    /**
     * Return <code>true if the context-relative request path
     * matches the requirements of the specified filter mapping;
     * otherwise, return <code>false.
     *
     * @param filterMap Filter mapping being checked
     * @param requestPath Context-relative request path of this request
     */
    private boolean matchFiltersURL(FilterMap filterMap, String requestPath) {

        // Check the specific "*" special URL pattern, which also matches
        // named dispatches
        if (filterMap.getMatchAllUrlPatterns())
            return (true);
        
        if (requestPath == null)
            return (false);

        // Match on context relative request path
        String[] testPaths = filterMap.getURLPatterns();
        
        for (int i = 0; i < testPaths.length; i++) {
            if (matchFiltersURL(testPaths[i], requestPath)) {
                return (true);
            }
        }
        
        // No match
        return (false);
        
    }
    

    /**
     * Return <code>true if the context-relative request path
     * matches the requirements of the specified filter mapping;
     * otherwise, return <code>false.
     *
     * @param testPath URL mapping being checked
     * @param requestPath Context-relative request path of this request
     */
    private boolean matchFiltersURL(String testPath, String requestPath) {
        
        if (testPath == null)
            return (false);

        // Case 1 - Exact Match
        if (testPath.equals(requestPath))
            return (true);

        // Case 2 - Path Match ("/.../*")
        if (testPath.equals("/*"))
            return (true);
        if (testPath.endsWith("/*")) {
            if (testPath.regionMatches(0, requestPath, 0, 
                                       testPath.length() - 2)) {
                if (requestPath.length() == (testPath.length() - 2)) {
                    return (true);
                } else if ('/' == requestPath.charAt(testPath.length() - 2)) {
                    return (true);
                }
            }
            return (false);
        }

        // Case 3 - Extension Match
        if (testPath.startsWith("*.")) {
            int slash = requestPath.lastIndexOf('/');
            int period = requestPath.lastIndexOf('.');
            if ((slash >= 0) && (period > slash) 
                && (period != requestPath.length() - 1)
                && ((requestPath.length() - period) 
                    == (testPath.length() - 1))) {
                return (testPath.regionMatches(2, requestPath, period + 1,
                                               testPath.length() - 2));
            }
        }

        // Case 4 - "Default" Match
        return (false); // NOTE - Not relevant for selecting filters

    }


    /**
     * Return <code>true if the specified servlet name matches
     * the requirements of the specified filter mapping; otherwise
     * return <code>false.
     *
     * @param filterMap Filter mapping being checked
     * @param servletName Servlet name being checked
     */
    private boolean matchFiltersServlet(FilterMap filterMap, 
                                        String servletName) {

        if (servletName == null) {
            return (false);
        }
        // Check the specific "*" special servlet name
        else if (filterMap.getMatchAllServletNames()) {
            return (true);
        } else {
            String[] servletNames = filterMap.getServletNames();
            for (int i = 0; i < servletNames.length; i++) {
                if (servletName.equals(servletNames[i])) {
                    return (true);
                }
            }
            return false;
        }

    }


    /**
     * Convienience method which returns true if  the dispatcher type
     * matches the dispatcher types specified in the FilterMap
     */
    private boolean matchDispatcher(FilterMap filterMap, int dispatcher) {
        switch (dispatcher) {
            case FORWARD : {
                if (filterMap.getDispatcherMapping() == FilterMap.FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.FORWARD_ERROR ||
                    filterMap.getDispatcherMapping() == FilterMap.INCLUDE_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.INCLUDE_ERROR_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_FORWARD_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_FORWARD_INCLUDE) {
                        return true;
                }
                break;
            }
            case INCLUDE : {
                if (filterMap.getDispatcherMapping() == FilterMap.INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.INCLUDE_ERROR ||
                    filterMap.getDispatcherMapping() == FilterMap.INCLUDE_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.INCLUDE_ERROR_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_FORWARD_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_FORWARD_INCLUDE) {
                        return true;
                }
                break;
            }
            case REQUEST : {
                if (filterMap.getDispatcherMapping() == FilterMap.REQUEST ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_FORWARD_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_FORWARD_INCLUDE) {
                        return true;
                }
                break;
            }
            case ERROR : {
                if (filterMap.getDispatcherMapping() == FilterMap.ERROR ||
                    filterMap.getDispatcherMapping() == FilterMap.FORWARD_ERROR || 
                    filterMap.getDispatcherMapping() == FilterMap.INCLUDE_ERROR || 
                    filterMap.getDispatcherMapping() == FilterMap.INCLUDE_ERROR_FORWARD || 
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_FORWARD ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_FORWARD_INCLUDE ||
                    filterMap.getDispatcherMapping() == FilterMap.REQUEST_ERROR_INCLUDE) {
                        return true;
                }
                break;
            }
        }
        return false;
    }


}