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


1 /******************************************************************
2  * File: Remove.java
3  * Created by: Dave Reynolds
4  * Created on: 11-Apr-2003
5  *
6  * (c) Copyright 2003, 2004, 2005 Hewlett-Packard Development Company, LP
7  * [See end of file]
8  * $Id: Remove.java,v 1.9 2005/02/21 12:17:33 andy_seaborne Exp $
9  *****************************************************************/
10 package com.hp.hpl.jena.reasoner.rulesys.builtins;
11
12 import com.hp.hpl.jena.reasoner.TriplePattern;
13 import com.hp.hpl.jena.reasoner.rulesys.*;
14 import com.hp.hpl.jena.graph.*;
15
16 /**
17  * Remove the body clause given by index arguments from the database.
18  *
19  * @author <a HREF="mailto:der@hplb.hpl.hp.com">Dave Reynolds</a>
20  * @version $Revision: 1.9 $ on $Date: 2005/02/21 12:17:33 $
21  */
22 public class Remove extends BaseBuiltin {
23
24     /**
25      * Return a name for this builtin, normally this will be the name of the
26      * functor that will be used to invoke it.
27      */
28     public String JavaDoc getName() {
29         return "remove";
30     }
31     
32     /**
33      * This method is invoked when the builtin is called in a rule head.
34      * Such a use is only valid in a forward rule.
35      * @param args the array of argument values for the builtin, this is an array
36      * of Nodes.
37      * @param length the length of the argument list, may be less than the length of the args array
38      * for some rule engines
39      * @param context an execution context giving access to other relevant data
40      */
41     public void headAction(Node[] args, int length, RuleContext context) {
42         boolean ok = false;
43         for (int i = 0; i < length; i++) {
44             Node clauseN = getArg(i, args, context);
45             if (Util.isNumeric(clauseN)) {
46                 int clauseIndex = Util.getIntValue(clauseN);
47                 Object JavaDoc clause = context.getRule().getBodyElement(clauseIndex);
48                 if (clause instanceof TriplePattern) {
49                     Triple t = context.getEnv().instantiate((TriplePattern)clause);
50                     context.remove(t);
51                 } else {
52                     throw new BuiltinException(this, context, "illegal triple to remove non-triple clause");
53                 }
54             } else {
55                 throw new BuiltinException(this, context, "illegal arg to remove (" + clauseN + "), must be an integer");
56             }
57         }
58     }
59 }
60
61 /*
62     (c) Copyright 2003, 2004, 2005 Hewlett-Packard Development Company, LP
63     All rights reserved.
64
65     Redistribution and use in source and binary forms, with or without
66     modification, are permitted provided that the following conditions
67     are met:
68
69     1. Redistributions of source code must retain the above copyright
70        notice, this list of conditions and the following disclaimer.
71
72     2. Redistributions in binary form must reproduce the above copyright
73        notice, this list of conditions and the following disclaimer in the
74        documentation and/or other materials provided with the distribution.
75
76     3. The name of the author may not be used to endorse or promote products
77        derived from this software without specific prior written permission.
78
79     THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
80     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
81     OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
82     IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
83     INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
84     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
85     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
86     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
87     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
88     THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
89 */
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