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


1 /******************************************************************
2  * File: ListMapAsSubject.java
3  * Created by: Dave Reynolds
4  * Created on: 23-Sep-2003
5  *
6  * (c) Copyright 2003, 2004, 2005 Hewlett-Packard Development Company, LP, all rights reserved.
7  * [See end of file]
8  * $Id: ListMapAsSubject.java,v 1.6 2005/02/21 12:17:28 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 import java.util.*;
15
16 /**
17  * For each element in the RDF list (first argument) it asserts
18  * triples with that as the subject and predicate and object given by arguments
19  * two and three. A strange and hacky function, only usable in the head of
20  * forward rules.
21  *
22  * @author <a HREF="mailto:der@hplb.hpl.hp.com">Dave Reynolds</a>
23  * @version $Revision: 1.6 $ on $Date: 2005/02/21 12:17:28 $
24  */
25 public class ListMapAsSubject extends BaseBuiltin {
26
27     /**
28      * Return a name for this builtin, normally this will be the name of the
29      * functor that will be used to invoke it.
30      */
31     public String JavaDoc getName() {
32         return "listMapAsSubject";
33     }
34     
35     /**
36      * Return the expected number of arguments for this functor or 0 if the number is flexible.
37      */
38     public int getArgLength() {
39         return 3;
40     }
41     
42     /**
43      * This method is invoked when the builtin is called in a rule head.
44      * Such a use is only valid in a forward rule.
45      * @param args the array of argument values for the builtin, this is an array
46      * of Nodes.
47      * @param length the length of the argument list, may be less than the length of the args array
48      * for some rule engines
49      * @param context an execution context giving access to other relevant data
50      */
51     public void headAction(Node[] args, int length, RuleContext context) {
52         checkArgs(length, context);
53         Node n0 = getArg(0, args, context);
54         Node n1 = getArg(1, args, context);
55         Node n2 = getArg(2, args, context);
56         List l = Util.convertList(n0, context);
57         for (Iterator i = l.iterator(); i.hasNext(); ) {
58             Node x = (Node)i.next();
59             context.add( new Triple(x, n1, n2));
60         }
61     }
62     
63 }
64
65
66
67 /*
68     (c) Copyright 2003, 2004, 2005 Hewlett-Packard Development Company, LP
69     All rights reserved.
70
71     Redistribution and use in source and binary forms, with or without
72     modification, are permitted provided that the following conditions
73     are met:
74
75     1. Redistributions of source code must retain the above copyright
76        notice, this list of conditions and the following disclaimer.
77
78     2. Redistributions in binary form must reproduce the above copyright
79        notice, this list of conditions and the following disclaimer in the
80        documentation and/or other materials provided with the distribution.
81
82     3. The name of the author may not be used to endorse or promote products
83        derived from this software without specific prior written permission.
84
85     THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
86     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
87     OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
88     IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
89     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
90     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
91     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
92     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
93     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
94     THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
95 */
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