1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/ConcatFunction.java,v 1.9 2006/02/05 21:47:41 elharo Exp $
3 * $Revision: 1.9 $
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: ConcatFunction.java,v 1.9 2006/02/05 21:47:41 elharo Exp $
46 */
47
48
49 package org.jaxen.function;
50
51 import java.util.Iterator;
52 import java.util.List;
53
54 import org.jaxen.Context;
55 import org.jaxen.Function;
56 import org.jaxen.FunctionCallException;
57 import org.jaxen.Navigator;
58
59 /***
60 * <b>4.2</b> <code><i>string</i> concat(<i>string</i>,<i>string</i>,<i>string*</i>)</code>
61 * <p>
62 * Concatenates its arguments and returns the resulting string.
63 * </p>
64 *
65 * @author bob mcwhirter (bob@werken.com)
66 *
67 * @see <a href="http://www.w3.org/TR/xpath#function-concat">Section 4.2 of the XPath Specification</a>
68 */
69 public class ConcatFunction implements Function
70 {
71
72 /***
73 * Create a new <code>ConcatFunction</code> object.
74 */
75 public ConcatFunction() {}
76
77 /***
78 * Concatenates the arguments and returns the resulting string.
79 * Non-string items are first converted to strings as if by the
80 * XPath <code>string()<code> function.
81 *
82 * @param context the context at the point in the
83 * expression when the function is called
84 * @param args the list of strings to be concatenated
85 *
86 * @return a <code>String</code> containing the concatenation of the items
87 * of <code>args</code>
88 *
89 * @throws FunctionCallException if <code>args</code> has less than two items
90 */
91 public Object call(Context context,
92 List args) throws FunctionCallException
93 {
94 if ( args.size() >= 2 )
95 {
96 return evaluate( args,
97 context.getNavigator() );
98 }
99
100 throw new FunctionCallException("concat() requires at least two arguments");
101 }
102
103 /***
104 * Converts each item in the list to a string and returns the
105 * concatenation of these strings.
106 * If necessary, each item is first converted to a <code>String</code>
107 * as if by the XPath <code>string()</code> function.
108 *
109 * @param list the items to be concatenated
110 * @param nav ignored
111 *
112 * @return the concatenation of the arguments
113 */
114 public static String evaluate(List list,
115 Navigator nav)
116 {
117 StringBuffer result = new StringBuffer();
118 Iterator argIter = list.iterator();
119 while ( argIter.hasNext() )
120 {
121 result.append( StringFunction.evaluate( argIter.next(),
122 nav ) );
123 }
124
125 return result.toString();
126 }
127 }