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;
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 call(Context context,
118 List 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 evaluate(Object strArg,
148 Navigator nav)
149 {
150 String 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(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 }