ContainsFunction


1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/ContainsFunction.java,v 1.7 2005/06/26 16:07:23 elharo Exp $
3    * $Revision: 1.7 $
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: ContainsFunction.java,v 1.7 2005/06/26 16:07:23 elharo Exp $
60   */
61  
62  package org.jaxen.function;
63  
64  import java.util.List  ;
65  
66  import org.jaxen.Context;
67  import org.jaxen.Function;
68  import org.jaxen.FunctionCallException;
69  import org.jaxen.Navigator;
70  
71  /**
72   *  <p><b>4.2</b> <code><i>boolean</i> contains(<i>string</i>,<i>string</i>)</code> 
73   *  
74   * <blockquote SRC="http://www.w3.org/TR/xpath">
75   * The <b>contains</b> function returns true if the first argument 
76   * string contains the second argument string, and otherwise returns false.
77   * </blockquote>
78   * 
79   * @author bob mcwhirter (bob @ werken.com)
80   * 
81   * @see <a HREF="http://www.w3.org/TR/xpath#function-contains">Section 4.2 of the XPath Specification</a>
82   */
83  public class ContainsFunction implements Function
84  {
85  
86      /**
87       * Create a new <code>ContainsFunction</code> object.
88       */
89      public ContainsFunction() {}
90      
91      /** 
92       * <p>
93       *  Returns true if the string-value of the 
94       *  first item in <code>args</code> contains string-value of the second 
95       *  item; false otherwise.
96       *  If necessary one or both items are converted to a string as if by the XPath
97       *  <code>string()</code> function.
98       * </p>
99       *
100      * @param context the context at the point in the
101      *         expression when the function is called
102      * @param args a list containing exactly two items
103      * 
104      * @return the result of evaluating the function; 
105      *     <code>Boolean.TRUE</code> or <code>Boolean.FALSE</code>
106      * 
107      * @throws FunctionCallException if <code>args</code> does not have exactly two items
108      */
109     public Object   call(Context context,
110                        List   args) throws FunctionCallException
111     {
112         if (args.size() == 2)
113         {
114             return evaluate(args.get(0),
115                             args.get(1),
116                             context.getNavigator() );
117         }
118 
119         throw new FunctionCallException("contains() requires two arguments.");
120     }
121 
122     /** 
123      * <p>Returns true if the first string contains the second string; false otherwise.
124      * If necessary one or both arguments are converted to a string as if by the XPath
125      * <code>string()</code> function.
126      * </p>
127      * 
128      * @param strArg the containing string
129      * @param matchArg the contained string
130      * @param nav used to calculate the string-values of the first two arguments
131      * 
132      * @return <code>Boolean.TRUE</code> if true if the first string contains 
133      *     the second string; <code>Boolean.FALSE</code> otherwise.
134      */
135     public static Boolean   evaluate(Object   strArg,
136                                    Object   matchArg,
137                                    Navigator nav) 
138     {
139         String   str   = StringFunction.evaluate( strArg,
140                                                 nav );
141 
142         String   match = StringFunction.evaluate( matchArg,
143                                                 nav );
144 
145         return ( ( str.indexOf(match) >= 0)
146                  ? Boolean.TRUE
147                  : Boolean.FALSE
148                  );
149     }
150 }
151
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