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Java > Open Source Codes > com > hp > hpl > jena > reasoner > rulesys > builtins > IsBNode


1 /******************************************************************
2  * File: IsBNode.java
3  * Created by: Dave Reynolds
4  * Created on: 24-Aug-2003
5  *
6  * (c) Copyright 2003, 2004, 2005 Hewlett-Packard Development Company, LP
7  * [See end of file]
8  * $Id: IsBNode.java,v 1.5 2005/02/21 12:17:24 andy_seaborne Exp $
9  *****************************************************************/
10 package com.hp.hpl.jena.reasoner.rulesys.builtins;
11
12 import com.hp.hpl.jena.reasoner.rulesys.*;
13 import com.hp.hpl.jena.graph.*;
14
15 /**
16  * Tests the single argument to make sure it is blank node.
17  *
18  * @author <a HREF="mailto:der@hplb.hpl.hp.com">Dave Reynolds</a>
19  * @version $Revision: 1.5 $ on $Date: 2005/02/21 12:17:24 $
20  */
21 public class IsBNode extends BaseBuiltin {
22
23     /**
24      * Return a name for this builtin, normally this will be the name of the
25      * functor that will be used to invoke it.
26      */
27     public String JavaDoc getName() {
28         return "isBNode";
29     }
30     
31     /**
32      * Return the expected number of arguments for this functor or 0 if the number is flexible.
33      */
34     public int getArgLength() {
35         return 1;
36     }
37
38     /**
39      * This method is invoked when the builtin is called in a rule body.
40      * @param args the array of argument values for the builtin, this is an array
41      * of Nodes, some of which may be Node_RuleVariables.
42      * @param length the length of the argument list, may be less than the length of the args array
43      * for some rule engines
44      * @param context an execution context giving access to other relevant data
45      * @return return true if the buildin predicate is deemed to have succeeded in
46      * the current environment
47      */
48     public boolean bodyCall(Node[] args, int length, RuleContext context) {
49         checkArgs(length, context);
50         return getArg(0, args, context).isBlank();
51     }
52     
53 }
54
55
56
57 /*
58     (c) Copyright 2003, 2004, 2005 Hewlett-Packard Development Company, LP
59     All rights reserved.
60
61     Redistribution and use in source and binary forms, with or without
62     modification, are permitted provided that the following conditions
63     are met:
64
65     1. Redistributions of source code must retain the above copyright
66        notice, this list of conditions and the following disclaimer.
67
68     2. Redistributions in binary form must reproduce the above copyright
69        notice, this list of conditions and the following disclaimer in the
70        documentation and/or other materials provided with the distribution.
71
72     3. The name of the author may not be used to endorse or promote products
73        derived from this software without specific prior written permission.
74
75     THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
76     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
77     OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
78     IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
79     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
80     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
81     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
82     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
83     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
84     THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
85 */
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