KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > jaxen > function > NormalizeSpaceFunction


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NormalizeSpaceFunction.java,v 1.15 2005/06/26 16:07:23 elharo Exp $
3  * $Revision: 1.15 $
4  * $Date: 2005/06/26 16:07:23 $
5  *
6  * ====================================================================
7  *
8  * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  *
15  * 1. Redistributions of source code must retain the above copyright
16  * notice, this list of conditions, and the following disclaimer.
17  *
18  * 2. Redistributions in binary form must reproduce the above copyright
19  * notice, this list of conditions, and the disclaimer that follows
20  * these conditions in the documentation and/or other materials
21  * provided with the distribution.
22  *
23  * 3. The name "Jaxen" must not be used to endorse or promote products
24  * derived from this software without prior written permission. For
25  * written permission, please contact license@jaxen.org.
26  *
27  * 4. Products derived from this software may not be called "Jaxen", nor
28  * may "Jaxen" appear in their name, without prior written permission
29  * from the Jaxen Project Management (pm@jaxen.org).
30  *
31  * In addition, we request (but do not require) that you include in the
32  * end-user documentation provided with the redistribution and/or in the
33  * software itself an acknowledgement equivalent to the following:
34  * "This product includes software developed by the
35  * Jaxen Project (http://www.jaxen.org/)."
36  * Alternatively, the acknowledgment may be graphical using the logos
37  * available at http://www.jaxen.org/
38  *
39  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42  * DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * ====================================================================
53  * This software consists of voluntary contributions made by many
54  * individuals on behalf of the Jaxen Project and was originally
55  * created by bob mcwhirter <bob@werken.com> and
56  * James Strachan <jstrachan@apache.org>. For more information on the
57  * Jaxen Project, please see <http://www.jaxen.org/>.
58  *
59  * $Id: NormalizeSpaceFunction.java,v 1.15 2005/06/26 16:07:23 elharo Exp $
60  */
61
62
63 package org.jaxen.function;
64
65 import java.util.List JavaDoc;
66
67 import org.jaxen.Context;
68 import org.jaxen.Function;
69 import org.jaxen.FunctionCallException;
70 import org.jaxen.Navigator;
71
72 /**
73  * <p>
74  * <b>4.2</b> <code><i>string</i> normalize-space(<i>string</i>)</code>
75  * </p>
76  *
77  * <blockquote SRC="http://www.w3.org/TR/xpath#function-normalize-space">
78  * The <b>normalize-space</b> function
79  * returns the argument string with whitespace normalized by stripping
80  * leading and trailing whitespace and replacing sequences of whitespace
81  * characters by a single space. Whitespace characters are the same as
82  * those allowed by the <a HREF="http://www.w3.org/TR/REC-xml#NT-S" target="_top">S</a>
83  * production in XML. If the argument is omitted, it defaults to the
84  * context node converted to a string, in other words the <a
85  * HREF="http://www.w3.org/TR/xpath#dt-string-value"
86  * target="_top">string-value</a> of the context node.
87  * </blockquote>
88  *
89  * @author James Strachan (james@metastuff.com)
90  * @see <a HREF="http://www.w3.org/TR/xpath#function-normalize-space"
91  * target="_top">Section 4.2 of the XPath Specification</a>
92  */
93 public class NormalizeSpaceFunction implements Function
94 {
95
96
97     /**
98      * Create a new <code>NormalizeSpaceFunction</code> object.
99      */
100     public NormalizeSpaceFunction() {}
101     
102     /**
103      * Returns the string-value of the first item in <code>args</code>
104      * after removing all leading and trailing white space, and
105      * replacing each other sequence of whitespace by a single space.
106      * Whitespace consists of the characters space (0x32), carriage return (0x0D),
107      * linefeed (0x0A), and tab (0x09).
108      *
109      * @param context the context at the point in the
110      * expression when the function is called
111      * @param args a list that contains exactly one item
112      *
113      * @return a normalized <code>String</code>
114      *
115      * @throws FunctionCallException if <code>args</code> does not have length one
116      */
117     public Object JavaDoc call(Context context,
118                        List JavaDoc args) throws FunctionCallException
119     {
120         
121         if (args.size() == 0) {
122             return evaluate( context.getNodeSet(),
123                              context.getNavigator() );
124         }
125         else if (args.size() == 1)
126         {
127             return evaluate( args.get(0),
128                              context.getNavigator() );
129         }
130     
131         throw new FunctionCallException( "normalize-space() cannot have more than one argument" );
132     }
133
134     /**
135      * Returns the string-value of <code>strArg</code> after removing
136      * all leading and trailing white space, and
137      * replacing each other sequence of whitespace by a single space.
138      * Whitespace consists of the characters space (0x32), carriage return (0x0D),
139      * linefeed (0x0A), and tab (0x09).
140      *
141      * @param strArg the object whose string-value is normalized
142      * @param nav the context at the point in the
143      * expression when the function is called
144      *
145      * @return the normalized string-value
146      */
147     public static String JavaDoc evaluate(Object JavaDoc strArg,
148                                   Navigator nav)
149     {
150         String JavaDoc str = StringFunction.evaluate( strArg,
151                                               nav );
152
153         char[] buffer = str.toCharArray();
154         int write = 0;
155         int lastWrite = 0;
156         boolean wroteOne = false;
157         int read = 0;
158         while (read < buffer.length)
159         {
160             if (isXMLSpace(buffer[read]))
161             {
162                 if (wroteOne)
163                 {
164                     buffer[write++] = ' ';
165                 }
166                 do
167                 {
168                     read++;
169                 }
170                 while(read < buffer.length && isXMLSpace(buffer[read]));
171             }
172             else
173             {
174                 buffer[write++] = buffer[read++];
175                 wroteOne = true;
176                 lastWrite = write;
177             }
178         }
179
180         return new String JavaDoc(buffer, 0, lastWrite);
181     }
182     
183     
184     private static boolean isXMLSpace(char c) {
185         return c == ' ' || c == '\n' || c == '\r' || c == '\t';
186     }
187     
188 }
189
Popular Tags