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Java > Open Source Codes > com > Yasna > forum > filter > FilterHtml


1 /**
2  * Copyright (C) 2001 Yasna.com. All rights reserved.
3  *
4  * ===================================================================
5  * The Apache Software License, Version 1.1
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in
16  * the documentation and/or other materials provided with the
17  * distribution.
18  *
19  * 3. The end-user documentation included with the redistribution,
20  * if any, must include the following acknowledgment:
21  * "This product includes software developed by
22  * Yasna.com (http://www.yasna.com)."
23  * Alternately, this acknowledgment may appear in the software itself,
24  * if and wherever such third-party acknowledgments normally appear.
25  *
26  * 4. The names "Yazd" and "Yasna.com" must not be used to
27  * endorse or promote products derived from this software without
28  * prior written permission. For written permission, please
29  * contact yazd@yasna.com.
30  *
31  * 5. Products derived from this software may not be called "Yazd",
32  * nor may "Yazd" appear in their name, without prior written
33  * permission of Yasna.com.
34  *
35  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38  * DISCLAIMED. IN NO EVENT SHALL YASNA.COM OR
39  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46  * SUCH DAMAGE.
47  * ====================================================================
48  *
49  * This software consists of voluntary contributions made by many
50  * individuals on behalf of Yasna.com. For more information
51  * on Yasna.com, please see <http://www.yasna.com>.
52  */

53
54 /**
55  * Copyright (C) 2000 CoolServlets.com. All rights reserved.
56  *
57  * ===================================================================
58  * The Apache Software License, Version 1.1
59  *
60  * Redistribution and use in source and binary forms, with or without
61  * modification, are permitted provided that the following conditions
62  * are met:
63  *
64  * 1. Redistributions of source code must retain the above copyright
65  * notice, this list of conditions and the following disclaimer.
66  *
67  * 2. Redistributions in binary form must reproduce the above copyright
68  * notice, this list of conditions and the following disclaimer in
69  * the documentation and/or other materials provided with the
70  * distribution.
71  *
72  * 3. The end-user documentation included with the redistribution,
73  * if any, must include the following acknowledgment:
74  * "This product includes software developed by
75  * CoolServlets.com (http://www.coolservlets.com)."
76  * Alternately, this acknowledgment may appear in the software itself,
77  * if and wherever such third-party acknowledgments normally appear.
78  *
79  * 4. The names "Jive" and "CoolServlets.com" must not be used to
80  * endorse or promote products derived from this software without
81  * prior written permission. For written permission, please
82  * contact webmaster@coolservlets.com.
83  *
84  * 5. Products derived from this software may not be called "Jive",
85  * nor may "Jive" appear in their name, without prior written
86  * permission of CoolServlets.com.
87  *
88  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
89  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
90  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
91  * DISCLAIMED. IN NO EVENT SHALL COOLSERVLETS.COM OR
92  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
93  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
94  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
95  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
96  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
97  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
98  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
99  * SUCH DAMAGE.
100  * ====================================================================
101  *
102  * This software consists of voluntary contributions made by many
103  * individuals on behalf of CoolServlets.com. For more information
104  * on CoolServlets.com, please see <http://www.coolservlets.com>.
105  */

106  
107 package com.Yasna.forum.filter;
108
109 import java.util.*;
110 import java.io.*;
111
112 import com.Yasna.forum.*;
113 import com.Yasna.codeviewer.*;
114
115 /**
116  * A ForumMessageFilter that escapes all HTML tags to prevent a user
117  * from embedding arbitrary HTML in a message.
118  */

119 public class FilterHtml extends ForumMessageFilter implements Serializable {
120
121     /**
122      * Property values of the filter.
123      */

124     private Properties props;
125
126     /**
127      * Property descriptions of the filter.
128      */

129     private Properties propDescriptions;
130
131     /**
132      * Creates a new filter not associated with a message. This is
133      * generally only useful for defining a template filter that other
134      * fitlers will be cloned from.
135      */

136     public FilterHtml() {
137         super();
138         props = new Properties();
139         propDescriptions = new Properties();
140     }
141
142     /**
143      * Creates a new filter wrapped around the specified message. This
144      * constructor is normally called when cloning a filter template.
145      *
146      * @param message the ForumMessage to wrap the new filter around.
147      * @param properties the property values for the filter.
148      * @param propertyDescriptions the property descriptions for the filter.
149      */

150     public FilterHtml(ForumMessage message, Properties props,
151             Properties propDescriptions)
152     {
153         super(message);
154         this.props = new Properties(props);
155         this.propDescriptions = new Properties(propDescriptions);
156     }
157
158     /**
159      * Clones a new filter that will have the same properties and that
160      * will wrap around the specified message.
161      *
162      * @param message the ForumMessage to wrap the new filter around.
163      */

164     public ForumMessageFilter clone(ForumMessage message){
165         return new FilterHtml(message,props,propDescriptions);
166     }
167
168     /**
169      * Returns the name of the filter.
170      */

171     public String JavaDoc getName() {
172         return "HTML Filter";
173     }
174
175     /**
176      * Returns a description of the filter.
177      */

178     public String JavaDoc getDescription() {
179         return "Escapes HTML tags by converting &lt; and &gt; characters " +
180                 "into HTML esacpe sequences.";
181     }
182
183     /**
184      * Returns the author of the filter.
185      */

186     public String JavaDoc getAuthor() {
187         return "CoolServlets.com";
188     }
189
190     /**
191      * Returns the major version number of the filter.
192      */

193     public int getMajorVersion() {
194         return 1;
195     }
196
197     /**
198      * Returns a description of the filter.
199      */

200     public int getMinorVersion() {
201         return 0;
202     }
203
204     /**
205      * Returns the value of a property of the filter.
206      *
207      * @param name the name of the property.
208      * @returns the value of the property.
209      */

210     public String JavaDoc getFilterProperty(String JavaDoc name) {
211         return props.getProperty(name);
212     }
213
214     /**
215      * Returns the description of a property of the filter.
216      *
217      * @param name the name of the property.
218      * @return the description of the property.
219      */

220     public String JavaDoc getFilterPropertyDescription(String JavaDoc name) {
221         return propDescriptions.getProperty(name);
222     }
223
224     /**
225      * Returns an Enumeration of all the property names.
226      */

227     public Enumeration filterPropertyNames() {
228         //No properties, so return null.
229
return null;
230     }
231
232     /**
233      * Sets a property of the filter. Each filter has a set number of
234      * properties that are determined by the filter author.
235      *
236      * @param name the name of the property to set.
237      * @param value the new value for the property.
238      *
239      * @throws IllegalArgumentException if the property trying to be set doesn't
240      * exist.
241      */

242     public void setFilterProperty(String JavaDoc name, String JavaDoc value)
243             throws IllegalArgumentException JavaDoc
244     {
245         if (props.getProperty(name) == null) {
246             throw new IllegalArgumentException JavaDoc();
247         }
248         props.put(name, value);
249     }
250
251     /**
252      * <b>Overloaded</b> to return the subject of the message with HTML tags
253      * escaped.
254      */

255     public String JavaDoc getSubject() {
256         return escapeHTMLTags(message.getSubject());
257     }
258
259     /**
260      * <b>Overloaded</b> to return the body of the message with HTML tags
261      * escaped.
262      */

263     public String JavaDoc getBody() {
264         return escapeHTMLTags(message.getBody());
265     }
266
267     /**
268      * This method takes a string which may contain HTML tags (ie, <b>, <table>,
269      * etc) and converts the '<' and '>' characters to their HTML escape
270      * sequences.
271      *
272      * @param input The text to be converted.
273      * @return The input string with the characters '<' and '>' replaced with
274      * &lt; and &gt; respectively.
275      */

276     private String JavaDoc escapeHTMLTags( String JavaDoc input ) {
277         //Check if the string is null or zero length -- if so, return
278
//what was sent in.
279
if( input == null || input.length() == 0 ) {
280             return input;
281         }
282         //Use a StringBuffer in lieu of String concatenation -- it is
283
//much more efficient this way.
284
StringBuffer JavaDoc buf = new StringBuffer JavaDoc(input.length()+6);
285         char ch = ' ';
286         for( int i=0; i<input.length(); i++ ) {
287             ch = input.charAt(i);
288             if( ch == '<' ) {
289                 buf.append( "&lt;" );
290             }
291             else if( ch == '>' ) {
292                 buf.append( "&gt;" );
293             }
294             else {
295                 buf.append( ch );
296             }
297         }
298         return buf.toString();
299     }
300 }
301
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