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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/SubstringAfterFunction.java,v 1.11 2006/02/05 21:47:41 elharo Exp $
3    * $Revision: 1.11 $
4    * $Date: 2006/02/05 21:47:41 $
5    *
6    * ====================================================================
7    *
8    * Copyright 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 are
13   * met:
14   * 
15   *   * Redistributions of source code must retain the above copyright
16   *     notice, this list of conditions and the following disclaimer.
17   * 
18   *   * Redistributions in binary form must reproduce the above copyright
19   *     notice, this list of conditions and the following disclaimer in the
20   *     documentation and/or other materials provided with the distribution.
21   * 
22   *   * Neither the name of the Jaxen Project nor the names of its
23   *     contributors may be used to endorse or promote products derived 
24   *     from this software without specific prior written permission.
25   * 
26   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37   *
38   * ====================================================================
39   * This software consists of voluntary contributions made by many 
40   * individuals on behalf of the Jaxen Project and was originally 
41   * created by bob mcwhirter <bob@werken.com> and 
42   * James Strachan <jstrachan@apache.org>.  For more information on the 
43   * Jaxen Project, please see <http://www.jaxen.org/>.
44   * 
45   * $Id: SubstringAfterFunction.java,v 1.11 2006/02/05 21:47:41 elharo Exp $
46   */
47  
48  
49  package org.jaxen.function;
50  
51  import java.util.List;
52  
53  import org.jaxen.Context;
54  import org.jaxen.Function;
55  import org.jaxen.FunctionCallException;
56  import org.jaxen.Navigator;
57  
58  /***
59   * <p><b>4.2</b> <code><i>string</i> substring-after(<i>string</i>,<i>string</i>)</code></p> 
60   * 
61   * 
62   * <blockquote src="http://www.w3.org/TR/xpath">
63   * The <b>substring-after</b> function returns the substring of the first argument string 
64   * that follows the first occurrence of the second argument string in the first 
65   * argument string, or the empty string if the first argument string does not contain the second argument string. 
66   * For example, substring-after("1999/04/01","/") returns 04/01, 
67   * and substring-after("1999/04/01","19") returns 99/04/01.
68   * </blockquote>
69   * 
70   * @author bob mcwhirter (bob @ werken.com)
71   * @see <a href="http://www.w3.org/TR/xpath#function-substring-after" target="_top">Section 4.2 of the XPath Specification</a>
72   */
73  public class SubstringAfterFunction implements Function
74  {
75  
76      /***
77       * Create a new <code>SubstringAfterFunction</code> object.
78       */
79      public SubstringAfterFunction() {}
80  
81  
82      /*** 
83       * Returns the part of the string-value of the first item in <code>args</code>
84       * that follows the string-value of the second item in <code>args</code>;
85       * or the empty string if the second string is not a substring of the first string.
86       *
87       * @param context the context at the point in the
88       *         expression when the function is called
89       * @param args a list that contains two items
90       * 
91       * @return a <code>String</code> containing that 
92       *     part of the string-value of the first item in <code>args</code>
93       *     that comes before the string-value of the second item in <code>args</code>
94       * 
95       * @throws FunctionCallException if <code>args</code> does not have length two
96       */
97      public Object call(Context context,
98                         List args) throws FunctionCallException
99      {
100         if (args.size() == 2)
101         {
102             return evaluate( args.get(0),
103                              args.get(1),
104                              context.getNavigator() );
105         }
106 
107         throw new FunctionCallException( "substring-after() requires two arguments." );
108     }
109 
110 
111     /*** 
112      * Returns the part of <code>strArg</code> that follows the first occurence 
113      * of <code>matchArg</code>; or the empty string if the 
114      * <code>strArg</code> does not contain <code>matchArg</code>
115      * 
116      * @param strArg the string from which the substring is extracted
117      * @param matchArg the string that marks the boundary of the substring
118      * @param nav the <code>Navigator</code> used to calculate the string-values of
119      *     the first two arguments
120      * 
121      * @return a <code>String</code> containing
122      *     the part of <code>strArg</code> that precedes the first occurence 
123      *     of <code>matchArg</code>
124      * 
125      */
126     public static String evaluate(Object strArg,
127                                   Object matchArg,
128                                   Navigator nav)
129     {
130         String str   = StringFunction.evaluate( strArg,
131                                                 nav );
132 
133         String match = StringFunction.evaluate( matchArg,
134                                                 nav );
135     
136         int loc = str.indexOf(match);
137 
138         if ( loc < 0 )
139         {
140             return "";
141         }
142 
143         return str.substring(loc+match.length());
144     }
145 }