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Java > Open Source Codes > org > apache > ecs > filter > WordFilter


1 /*
2  * ====================================================================
3  *
4  * The Apache Software License, Version 1.1
5  *
6  * Copyright (c) 1999-2003 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", "Jakarta Element Construction Set",
29  * "Jakarta ECS" , and "Apache Software Foundation" must not be used
30  * to endorse or promote products derived
31  * from this software without prior written permission. For written
32  * permission, please contact apache@apache.org.
33  *
34  * 5. Products derived from this software may not be called "Apache",
35  * "Jakarta Element Construction Set" nor "Jakarta ECS" nor may "Apache"
36  * appear in their names without prior written permission of the Apache Group.
37  *
38  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
39  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
40  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
41  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
42  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
43  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
44  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
45  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
46  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
47  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
48  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
49  * SUCH DAMAGE.
50  * ====================================================================
51  *
52  * This software consists of voluntary contributions made by many
53  * individuals on behalf of the Apache Software Foundation. For more
54  * information on the Apache Software Foundation, please see
55  * <http://www.apache.org/>.
56  *
57  */
58 package org.apache.ecs.filter;
59
60 import org.apache.ecs.Filter;
61 import java.text.StringCharacterIterator JavaDoc;
62 import java.text.CharacterIterator JavaDoc;
63 import java.util.StringTokenizer JavaDoc;
64
65 /**
66     This filter uses StringTokenizer to create "words" and allow
67     you to replace on those "words". A word is defined as anything
68     between two spaces. This filter should be relatively fast and
69     shows how easy it is to implement your own filters.
70
71 <pre><code>
72     Filter filter = new WordFilter();
73     filter.addAttribute("there","where");
74     filter.addAttribute("it","is");
75     filter.addAttribute("goes","it");
76     P p = new P();
77     p.setFilter(filter);
78     p.addElement("there it goes");
79     System.out.println(p.toString());
80 </code></pre>
81
82     Produces: &lt;p&gt;where is it
83
84     @version $Id: WordFilter.java,v 1.5 2003/04/27 09:28:56 rdonkin Exp $
85     @author <a HREF="mailto:snagy@servletapi.com">Stephan Nagy</a>
86     @author <a HREF="mailto:jon@clearink.com">Jon S. Stevens</a>
87 */
88 public class WordFilter extends java.util.Hashtable JavaDoc implements Filter
89 {
90     public WordFilter()
91     {
92         super(4);
93     }
94
95     /** Returns the name of the filter */
96     public String JavaDoc getInfo()
97     {
98         return "WordFilter";
99     }
100
101     /**
102         this method actually performs the filtering.
103     */
104     public String JavaDoc process(String JavaDoc to_process)
105     {
106         if ( to_process == null || to_process.length() == 0 )
107             return "";
108
109         String JavaDoc tmp = "";
110         // the true at the end is the key to making it work
111 StringTokenizer JavaDoc st = new StringTokenizer JavaDoc(to_process, " ", true);
112         StringBuffer JavaDoc newValue = new StringBuffer JavaDoc(to_process.length() + 50);
113         while ( st.hasMoreTokens() )
114         {
115             tmp = st.nextToken();
116             if (hasAttribute(tmp))
117                 newValue.append((String JavaDoc)get(tmp));
118             else
119                 newValue.append(tmp);
120         }
121         return newValue.toString();
122     }
123
124     /**
125         Put a filter somewhere we can get to it.
126     */
127     public Filter addAttribute(String JavaDoc attribute,Object JavaDoc entity)
128     {
129         put(attribute,entity);
130         return(this);
131     }
132
133     /**
134         Get rid of a current filter.
135     */
136     public Filter removeAttribute(String JavaDoc attribute)
137     {
138         try
139         {
140             remove(attribute);
141         }
142         catch(NullPointerException JavaDoc exc)
143         { // don't really care if this throws a null pointer exception
144 }
145         return(this);
146     }
147
148     /**
149         Does the filter filter this?
150     */
151     public boolean hasAttribute(String JavaDoc attribute)
152     {
153         return(containsKey(attribute));
154     }
155 }
156
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