##### Coverage Report - org.jaxen.function.StringLengthFunction

Classes in this File | Line Coverage | Branch Coverage | Complexity
StringLengthFunction |
90% |
100% |
| 4.666666666666667;4.667

1 |  |
     /*
2 |  |
      * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/StringLengthFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
3 |  |
      * $Revision: 1.10 $
4 |  |
      * $Date: 2005/06/28 13:44:45 $
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:
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      *
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      * 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.
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      *
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 |  |
      *
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      * 4. Products derived from this software may not be called "Jaxen", nor
28 |  |
      *    may "Jaxen" appear in their name, without prior written permission
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      *    from the Jaxen Project Management (pm@jaxen.org).
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      *
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      * 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/>."
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      * Alternatively, the acknowledgment may be graphical using the logos
37 |  |
      * available at http://www.jaxen.org/
38 |  |
      *
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      * 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 |  |
      * ====================================================================
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      * 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: StringLengthFunction.java,v 1.10 2005/06/28 13:44:45 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><b>4.2</b> <code><i>number</i> string-length(<i>string</i>)</code></p>
74 |  |
      *
75 |  |
      * <p>
76 |  |
      * The <b>string-length</b> function returns the number of <strong>Unicode characters</strong>
77 |  |
      * in its argument. This is <strong>not</strong> necessarily
78 |  |
      * the same as the number <strong>Java chars</strong>
79 |  |
      * in the corresponding Java string. In particular, if the Java <code>String</code>
80 |  |
      * contains surrogate pairs each such pair will be counted as only one character
81 |  |
      * by this function. If the argument is omitted,
82 |  |
      * it returns the length of the string-value of the context node.
83 |  |
      * </p>
84 |  |
      *
85 |  |
      * @author bob mcwhirter (bob @ werken.com)
86 |  |
      * @see <a href="http://www.w3.org/TR/xpath#function-string-length" target="_top">Section
87 |  |
      *      4.2 of the XPath Specification</a>
88 |  |
      */
89 |  |
     public class StringLengthFunction implements Function
90 |  |
     {
91 |  |
92 |  |
93 |  |
         /**
94 |  |
          * Create a new <code>StringLengthFunction</code> object.
95 |  |
          */
96 | 294 |
         public StringLengthFunction() {}
97 |  |
98 |  |
99 |  |
         /**
100 |  |
          * <p>
101 |  |
          * Returns the number of Unicode characters in the string-value of the argument.
102 |  |
          * </p>
103 |  |
          *
104 |  |
          * @param context the context at the point in the
105 |  |
          *         expression when the function is called
106 |  |
          * @param args a list containing the item whose string-value is to be counted.
107 |  |
          *     If empty, the length of the context node's string-value is returned.
108 |  |
          *
109 |  |
          * @return a <code>Double</code> giving the number of Unicode characters
110 |  |
          *
111 |  |
          * @throws FunctionCallException if args has more than one item
112 |  |
          */
113 |  |
         public Object call(Context context,
114 |  |
                            List args) throws FunctionCallException
115 |  |
         {
116 | 42 |
             if (args.size() == 0)
117 |  |
             {
118 | 6 |
                 return evaluate( context.getNodeSet(),
119 |  |
                                  context.getNavigator() );
120 |  |
             }
121 | 36 |
             else if (args.size() == 1)
122 |  |
             {
123 | 30 |
                 return evaluate( args.get(0),
124 |  |
                                  context.getNavigator() );
125 |  |
             }
126 |  |
127 | 6 |
             throw new FunctionCallException( "string-length() requires one argument." );
128 |  |
         }
129 |  |
130 |  |
         /**
131 |  |
          * <p>
132 |  |
          * Returns the number of Unicode characters in the string-value of
133 |  |
          * an object.
134 |  |
          * </p>
135 |  |
          *
136 |  |
          * @param obj the object whose string-value is counted
137 |  |
          * @param nav used to calculate the string-values of the first two arguments
138 |  |
          *
139 |  |
          * @return a <code>Double</code> giving the number of Unicode characters
140 |  |
          *
141 |  |
          * @throws FunctionCallException if the string contains mismatched surrogates
142 |  |
          */
143 |  |
         public static Double evaluate(Object obj, Navigator nav) throws FunctionCallException
144 |  |
         {
145 |  |
146 |  |
             // could/should I push the mismnatching checks into StringFunction.evaluate()????
147 | 336 |
             String str = StringFunction.evaluate( obj, nav );
148 |  |
             // String.length() counts UTF-16 code points; not Unicode characters
149 | 336 |
             char[] data = str.toCharArray();
150 | 336 |
             int length = 0;
151 | 1818 |
             for (int i = 0; i < data.length; i++) {
152 | 1488 |
                 char c = data[i];
153 | 1488 |
                 length++;
154 |  |
                 // if this is a high surrogate; assume the next character is
155 |  |
                 // is a low surrogate and skip it
156 | 1488 |
                 if (c >= 0xD800) {
157 |  |
                     try {
158 | 30 |
                         char low = data[i+1];
159 | 30 |
                         if (low < 0xDC00 || low > 0xDFFF) {
160 | 6 |
                             throw new FunctionCallException("Bad surrogate pair in string " + str);
161 |  |
                         }
162 | 24 |
                         i++; // increment past low surrogate
163 |  |
                     }
164 | 0 |
                     catch (ArrayIndexOutOfBoundsException ex) {
165 | 0 |
                         throw new FunctionCallException("Bad surrogate pair in string " + str);
166 | 24 |
                     }
167 |  |
                 }
168 |  |
             }
169 | 330 |
             return new Double(length);
170 |  |
         }
171 |  |
172 |  |
     }