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

Classes in this File | Line Coverage | Branch Coverage | Complexity
SubstringFunction |
98% |
100% |
| 9.333333333333334;9.333

1 |  |
     /*
2 |  |
      * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/SubstringFunction.java,v 1.15 2005/06/28 13:44:45 elharo Exp $
3 |  |
      * $Revision: 1.15 $
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:
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/>."
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      * 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 |  |
      * ====================================================================
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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 |  |
      */
60 |  |
     package org.jaxen.function;
61 |  |
62 |  |
     import java.util.List;
63 |  |
64 |  |
     import org.jaxen.Context;
65 |  |
     import org.jaxen.Function;
66 |  |
     import org.jaxen.FunctionCallException;
67 |  |
     import org.jaxen.Navigator;
68 |  |
     /**
69 |  |
      * <p>
70 |  |
      * <b>4.2</b>
71 |  |
      * <code><i>string</i> substring(<i>string</i>,<i>number</i>,<i>number?</i>)</code>
72 |  |
      * </p>
73 |  |
      *
74 |  |
      * <blockquote src="http://www.w3.org/TR/xpath">
75 |  |
      * <p>The <b>substring</b> function returns the
76 |  |
      * substring of the first argument starting at the position specified in
77 |  |
      * the second argument with length specified in the third argument. For
78 |  |
      * example,
79 |  |
      *
80 |  |
      * <code>substring("12345",2,3)</code> returns <code>"234"</code>.
81 |  |
      * If the third argument is not specified, it returns the substring
82 |  |
      * starting at the position specified in the second argument and
83 |  |
      * continuing to the end of the string. For example,
84 |  |
      * <code>substring("12345",2)</code> returns <code>"2345"</code>.
85 |  |
      * </p>
86 |  |
      *
87 |  |
      * <p>
88 |  |
      * More precisely, each character in the string (see <a
89 |  |
      * href="http://www.w3.org/TR/xpath#strings">[<b>3.6 Strings</b>]</a>) is considered to have a
90 |  |
      * numeric position: the position of the first character is 1, the
91 |  |
      * position of the second character is 2 and so on.
92 |  |
      * </p>
93 |  |
      *
94 |  |
      * <blockquote> <b>NOTE: </b>This differs from Java and ECMAScript, in
95 |  |
      * which the <code>String.substring</code> method treats the position
96 |  |
      * of the first character as 0.</blockquote>
97 |  |
      *
98 |  |
      * <p>
99 |  |
      * The returned substring contains those characters for which the
100 |  |
      * position of the character is greater than or equal to the rounded
101 |  |
      * value of the second argument and, if the third argument is specified,
102 |  |
      * less than the sum of the rounded value of the second argument and the
103 |  |
      * rounded value of the third argument; the comparisons and addition
104 |  |
      * used for the above follow the standard IEEE 754 rules; rounding is
105 |  |
      * done as if by a call to the <b><a href="#function-round">round</a></b>
106 |  |
      * function. The following examples illustrate various unusual cases:
107 |  |
      * </p>
108 |  |
      *
109 |  |
      * <ul>
110 |  |
      *
111 |  |
      * <li>
112 |  |
      * <p>
113 |  |
      * <code>substring("12345", 1.5, 2.6)</code> returns
114 |  |
      * <code>"234"</code>
115 |  |
      * </p>
116 |  |
      * </li>
117 |  |
      *
118 |  |
      * <li>
119 |  |
      * <p>
120 |  |
      * <code>substring("12345", 0, 3)</code> returns <code>"12"</code>
121 |  |
      *
122 |  |
      * </p>
123 |  |
      * </li>
124 |  |
      *
125 |  |
      * <li>
126 |  |
      * <p>
127 |  |
      * <code>substring("12345", 0 div 0, 3)</code> returns <code>""</code>
128 |  |
      * </p>
129 |  |
      * </li>
130 |  |
      *
131 |  |
      * <li>
132 |  |
      * <p>.
133 |  |
      * <code>substring("12345", 1, 0 div 0)</code> returns
134 |  |
      *
135 |  |
      * <code>""</code>
136 |  |
      * </p>
137 |  |
      * </li>
138 |  |
      *
139 |  |
      * <li>
140 |  |
      * <p>
141 |  |
      * <code>substring("12345", -42, 1 div 0)</code> returns
142 |  |
      * <code>"12345"</code>
143 |  |
      * </p>
144 |  |
      * </li>
145 |  |
      *
146 |  |
      * <li>
147 |  |
      * <p>
148 |  |
      *
149 |  |
      * <code>substring("12345", -1 div 0, 1 div 0)</code> returns
150 |  |
      * <code>""</code> </blockquote>
151 |  |
      *
152 |  |
      * @author bob mcwhirter (bob @ werken.com)
153 |  |
      *
154 |  |
      * @see <a href="http://www.w3.org/TR/xpath#function-substring"
155 |  |
      *      target="_top">Section 4.2 of the XPath Specification</a>
156 |  |
      */
157 |  |
     public class SubstringFunction implements Function
158 |  |
     {
159 |  |
160 |  |
         /**
161 |  |
          * Create a new <code>SubstringFunction</code> object.
162 |  |
          */
163 | 294 |
         public SubstringFunction() {}
164 |  |
165 |  |
166 |  |
         /** Returns a substring of an XPath string-value by character index.
167 |  |
          *
168 |  |
          * @param context the context at the point in the
169 |  |
          *         expression when the function is called
170 |  |
          * @param args a list that contains two or three items
171 |  |
          *
172 |  |
          * @return a <code>String</code> containing the specifed character subsequence of
173 |  |
          *     the original string or the string-value of the context node
174 |  |
          *
175 |  |
          * @throws FunctionCallException if <code>args</code> has more than three
176 |  |
          *     or less than two items
177 |  |
          */
178 |  |
         public Object call(Context context,
179 |  |
                            List args) throws FunctionCallException
180 |  |
         {
181 | 312 |
             final int argc = args.size();
182 | 312 |
             if (argc < 2 || argc > 3){
183 | 12 |
                 throw new FunctionCallException( "substring() requires two or three arguments." );
184 |  |
             }
185 |  |
186 | 300 |
             final Navigator nav = context.getNavigator();
187 |  |
188 | 300 |
             final String str = StringFunction.evaluate(args.get(0), nav );
189 |  |
             // The spec doesn't really address this case
190 | 300 |
             if (str == null) {
191 | 0 |
                 return "";
192 |  |
             }
193 |  |
194 | 300 |
             final int stringLength = (StringLengthFunction.evaluate(args.get(0), nav )).intValue();
195 |  |
196 | 300 |
             if (stringLength == 0) {
197 | 6 |
                 return "";
198 |  |
             }
199 |  |
200 | 294 |
             Double d1 = NumberFunction.evaluate(args.get(1), nav);
201 |  |
202 | 294 |
             if (d1.isNaN()){
203 | 30 |
                 return "";
204 |  |
             }
205 |  |
             // Round the value and subtract 1 as Java strings are zero based
206 | 264 |
             int start = RoundFunction.evaluate(d1, nav).intValue() - 1;
207 |  |
208 | 264 |
             int substringLength = stringLength;
209 | 264 |
             if (argc == 3){
210 | 222 |
                 Double d2 = NumberFunction.evaluate(args.get(2), nav);
211 |  |
212 | 222 |
                 if (!d2.isNaN()){
213 | 192 |
                     substringLength = RoundFunction.evaluate(d2, nav ).intValue();
214 |  |
                 }
215 |  |
                 else {
216 | 30 |
                     substringLength = 0;
217 |  |
                 }
218 |  |
             }
219 |  |
220 | 264 |
             if (substringLength < 0) return "";
221 |  |
222 | 252 |
             int end = start + substringLength;
223 | 252 |
             if (argc == 2) end = stringLength;
224 |  |
225 |  |
             // negative start is treated as 0
226 | 252 |
             if ( start < 0){
227 | 72 |
                 start = 0;
228 |  |
             }
229 | 180 |
             else if (start > stringLength){
230 | 30 |
                 return "";
231 |  |
             }
232 |  |
233 | 222 |
             if (end > stringLength){
234 | 66 |
                 end = stringLength;
235 |  |
             }
236 | 156 |
             else if (end < start) return "";
237 |  |
238 | 216 |
             if (stringLength == str.length()) {
239 |  |
                 // easy case; no surrogate pairs
240 | 198 |
                 return str.substring(start, end);
241 |  |
             }
242 |  |
             else {
243 | 18 |
                 return unicodeSubstring(str, start, end);
244 |  |
             }
245 |  |
246 |  |
         }
247 |  |
248 |  |
         private static String unicodeSubstring(String s, int start, int end) {
249 |  |
250 | 18 |
             StringBuffer result = new StringBuffer(s.length());
251 | 66 |
             for (int jChar = 0, uChar=0; uChar < end; jChar++, uChar++) {
252 | 48 |
                 char c = s.charAt(jChar);
253 | 48 |
                 if (uChar >= start) result.append(c);
254 | 48 |
                 if (c >= 0xD800) { // get the low surrogate
255 |  |
                     // ???? we could check here that this is indeed a low surroagte
256 |  |
                     // we could also catch StringIndexOutOfBoundsException
257 | 18 |
                     jChar++;
258 | 18 |
                     if (uChar >= start) result.append(s.charAt(jChar));
259 |  |
                 }
260 |  |
             }
261 | 18 |
             return result.toString();
262 |  |
         }
263 |  |
     }