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1   /*
2    * $Header$
3    * $Revision: 1128 $
4    * $Date: 2006-02-05 13:49:04 -0800 (Sun, 05 Feb 2006) $
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: ContainsFunction.java 1128 2006-02-05 21:49:04Z elharo $
46   */
47  
48  package org.jaxen.function;
49  
50  import java.util.List;
51  
52  import org.jaxen.Context;
53  import org.jaxen.Function;
54  import org.jaxen.FunctionCallException;
55  import org.jaxen.Navigator;
56  
57  /**
58   *  <p><b>4.2</b> <code><i>boolean</i> contains(<i>string</i>,<i>string</i>)</code></p>
59   *  
60   * <blockquote src="http://www.w3.org/TR/xpath">
61   * The <b>contains</b> function returns true if the first argument 
62   * string contains the second argument string, and otherwise returns false.
63   * </blockquote>
64   * 
65   * @author bob mcwhirter (bob @ werken.com)
66   * 
67   * @see <a href="http://www.w3.org/TR/xpath#function-contains">Section 4.2 of the XPath Specification</a>
68   */
69  public class ContainsFunction implements Function
70  {
71  
72      /**
73       * Create a new <code>ContainsFunction</code> object.
74       */
75      public ContainsFunction() {}
76      
77      /** 
78       * <p>
79       *  Returns true if the string-value of the 
80       *  first item in <code>args</code> contains string-value of the second 
81       *  item; false otherwise.
82       *  If necessary one or both items are converted to a string as if by the XPath
83       *  <code>string()</code> function.
84       * </p>
85       *
86       * @param context the context at the point in the
87       *         expression when the function is called
88       * @param args a list containing exactly two items
89       * 
90       * @return the result of evaluating the function; 
91       *     <code>Boolean.TRUE</code> or <code>Boolean.FALSE</code>
92       * 
93       * @throws FunctionCallException if <code>args</code> does not have exactly two items
94       */
95      public Object call(Context context,
96                         List args) throws FunctionCallException
97      {
98          if (args.size() == 2)
99          {
100             return evaluate(args.get(0),
101                             args.get(1),
102                             context.getNavigator() );
103         }
104 
105         throw new FunctionCallException("contains() requires two arguments.");
106     }
107 
108     /** 
109      * <p>Returns true if the first string contains the second string; false otherwise.
110      * If necessary one or both arguments are converted to a string as if by the XPath
111      * <code>string()</code> function.
112      * </p>
113      * 
114      * @param strArg the containing string
115      * @param matchArg the contained string
116      * @param nav used to calculate the string-values of the first two arguments
117      * 
118      * @return <code>Boolean.TRUE</code> if true if the first string contains 
119      *     the second string; <code>Boolean.FALSE</code> otherwise.
120      */
121     public static Boolean evaluate(Object strArg,
122                                    Object matchArg,
123                                    Navigator nav) 
124     {
125         String str   = StringFunction.evaluate( strArg,
126                                                 nav );
127 
128         String match = StringFunction.evaluate( matchArg,
129                                                 nav );
130 
131         return ( ( str.indexOf(match) >= 0)
132                  ? Boolean.TRUE
133                  : Boolean.FALSE
134                  );
135     }
136 }