1 /*
2 * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/FalseFunction.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: FalseFunction.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
57 /***
58 * <p><b>4.3</b> <code><i>boolean</i> false()</code>
59 *
60 * <p>Returns false.</p>
61 *
62 * @author bob mcwhirter (bob @ werken.com)
63 *
64 * @see <a href="http://www.w3.org/TR/xpath#function-false">Section 4.3 of the XPath Specification</a>
65 */
66 public class FalseFunction implements Function
67 {
68
69 /***
70 * Create a new <code>FalseFunction</code> object.
71 */
72 public FalseFunction() {}
73
74 /*** Returns <code>Boolean.FALSE</code>
75 *
76 * @param context the context at the point in the
77 * expression when the function is called
78 * @param args an empty list
79 *
80 * @return <code>Boolean.FALSE</code>
81 *
82 * @throws FunctionCallException if <code>args</code> is not empty
83 */
84 public Object call(Context context,
85 List args) throws FunctionCallException
86 {
87 if (args.size() == 0)
88 {
89 return evaluate();
90 }
91
92 throw new FunctionCallException( "false() requires no arguments." );
93 }
94
95 /***
96 * Returns false.
97 *
98 * @return <code>Boolean.FALSE</code>
99 */
100 public static Boolean evaluate()
101 {
102 return Boolean.FALSE;
103 }
104 }