1 /*
2 * ====================================================================
3 *
4 * The Apache Software License, Version 1.1
5 *
6 * Copyright (c) 2001-2002 The Apache Software Foundation. All rights
7 * reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in
18 * the documentation and/or other materials provided with the
19 * distribution.
20 *
21 * 3. The end-user documentation included with the redistribution, if
22 * any, must include the following acknowlegement:
23 * "This product includes software developed by the
24 * Apache Software Foundation (http://www.apache.org/)."
25 * Alternately, this acknowlegement may appear in the software itself,
26 * if and wherever such third-party acknowlegements normally appear.
27 *
28 * 4. The names "The Jakarta Project", "Stronghold" and "Apache Software
29 * Foundation" must not be used to endorse or promote products
30 * derived from this software without prior written permission. For
31 * written permission, please contact apache@apache.org.
32 *
33 * 5. Products derived from this software may not be called "Apache"
34 * nor may "Apache" appear in their names without prior written
35 * permission of the Apache Group.
36 *
37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48 * SUCH DAMAGE.
49 * ====================================================================
50 *
51 * This software consists of voluntary contributions made by many
52 * individuals on behalf of the Apache Software Foundation. For more
53 * information on the Apache Software Foundation, please see
54 * <http://www.apache.org/>;.
55 *
56 */
57 package org.apache.sesame.filter;
58
59 import org.apache.sesame.model.Request;
60 import org.apache.sesame.exception.MissingDataServletException;
61
62 import javax.servlet.Filter;
63 import javax.servlet.FilterConfig;
64 import javax.servlet.ServletException;
65 import javax.servlet.ServletRequest;
66 import javax.servlet.ServletResponse;
67 import javax.servlet.FilterChain;
68 import java.io.IOException;
69
70 /***
71 * Base Filter class for all Sesame Filters. It provides common helper methods
72 * such as easy access to model objects.
73 *
74 * @author <a href="mailto:vmassol@apache.org">Vincent Massol</a>
75 *
76 * @version $Id: AbstractFilter.java,v 1.4 2002/06/03 18:18:51 vmassol Exp $
77 */
78 public abstract class AbstractFilter implements Filter
79 {
80 /***
81 * Name under which the @{link Request} object is stored as an HTTP
82 * attribute.
83 */
84 private static final String HTTP_REQUEST_ATTRIBUTE =
85 "sesame.application.request";
86
87 /***
88 * The filter configuration object.
89 */
90 private FilterConfig config;
91
92 /***
93 * @see Filter#init(FilterConfig)
94 */
95 public void init(FilterConfig filterConfig) throws ServletException
96 {
97 this.config = filterConfig;
98 }
99
100 /***
101 * @see Filter#destroy()
102 */
103 public void destroy()
104 {
105 }
106
107 /***
108 * All Sesame filters must implement this method. This is where their
109 * execution code is placed. This is equivalent to the filter
110 * <code>doFilter</code> method but has been renamed so that this
111 * <code>AbstractFilter</code> filter can wrap it and perform additionnal
112 * actions such as managing exceptions and logging them, etc.
113 *
114 * @param servletRequest the incoming servlet request
115 * @param servletResponse the outgoing servelt response to send back
116 * @param filterChain the filter chain
117 * @throws IOException if an error occurs
118 * @throws ServletException if an error occurs
119 */
120 public abstract void execute(ServletRequest servletRequest,
121 ServletResponse servletResponse, FilterChain filterChain)
122 throws IOException, ServletException;
123
124 /***
125 * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
126 */
127 public void doFilter(ServletRequest servletRequest,
128 ServletResponse servletResponse, FilterChain filterChain)
129 throws IOException, ServletException
130 {
131 // Call the filter execute method and handle error conditions
132 try
133 {
134 execute(servletRequest, servletResponse, filterChain);
135 }
136 catch (MissingDataServletException e)
137 {
138 // TODO: log the exception here
139 throw e;
140 }
141 }
142
143 /***
144 * @param servletRequest the Servlet request
145 * @return the application {@link Request} object
146 * @throws ServletException if an error occurs
147 */
148 public Request getApplicationRequest(ServletRequest servletRequest)
149 throws ServletException
150 {
151 Request request =
152 (Request) servletRequest.getAttribute(HTTP_REQUEST_ATTRIBUTE);
153
154 if (request == null)
155 {
156 throw new MissingDataServletException("Cannot find attribute [" +
157 HTTP_REQUEST_ATTRIBUTE + "] in HTTP request");
158 }
159
160 return request;
161 }
162
163 /***
164 * @return the filter config object
165 */
166 public FilterConfig getFilterConfig()
167 {
168 return this.config;
169 }
170 }
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