1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/ConcatFunction.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: ConcatFunction.java,v 1.7 2005/06/26 16:07:23 elharo Exp $
60 */
61
62
63 package org.jaxen.function;
64
65 import java.util.Iterator;
66 import java.util.List;
67
68 import org.jaxen.Context;
69 import org.jaxen.Function;
70 import org.jaxen.FunctionCallException;
71 import org.jaxen.Navigator;
72
73 /***
74 * <b>4.2</b> <code><i>string</i> concat(<i>string</i>,<i>string</i>,<i>string*</i>)</code>
75 * <p>
76 * Concatenates its arguments and returns the resulting string.
77 * </p>
78 *
79 * @author bob mcwhirter (bob@werken.com)
80 *
81 * @see <a href="http://www.w3.org/TR/xpath#function-concat">Section 4.2 of the XPath Specification</a>
82 */
83 public class ConcatFunction implements Function
84 {
85
86 /***
87 * Create a new <code>ConcatFunction</code> object.
88 */
89 public ConcatFunction() {}
90
91 /***
92 * Concatenates the arguments and returns the resulting string.
93 * Non-string items are first converted to strings as if by the
94 * XPath <code>string()<code> function.
95 *
96 * @param context the context at the point in the
97 * expression when the function is called
98 * @param args the list of strings to be concatenated
99 *
100 * @return a <code>String</code> containing the concatenation of the items
101 * of <code>args</code>
102 *
103 * @throws FunctionCallException if <code>args</code> has less than two items
104 */
105 public Object call(Context context,
106 List args) throws FunctionCallException
107 {
108 if ( args.size() >= 2 )
109 {
110 return evaluate( args,
111 context.getNavigator() );
112 }
113
114 throw new FunctionCallException("concat() requires at least two arguments");
115 }
116
117 /***
118 * Converts each item in the list to a string and returns the
119 * concatenation of these strings.
120 * If necessary, each item is first converted to a <code>String</code>
121 * as if by the XPath <code>string()</code> function.
122 *
123 * @param list the items to be concatenated
124 * @param nav ignored
125 *
126 * @return the concatenation of the arguments
127 */
128 public static String evaluate(List list,
129 Navigator nav)
130 {
131 StringBuffer result = new StringBuffer();
132 Iterator argIter = list.iterator();
133 while ( argIter.hasNext() )
134 {
135 result.append( StringFunction.evaluate( argIter.next(),
136 nav ) );
137 }
138
139 return result.toString();
140 }
141 }