01: /*
02: * (c) Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008 Hewlett-Packard Development Company, LP
03: * [see end of file]
04: */
05:
06: package com.hp.hpl.jena.graph;
07:
08: /**
09: The Highlander Node_NULL exists for the database code (as a Node that
10: coresponds to a null in database tables for the reification code).
11:
12: @author kers
13: */
14:
15: public class Node_NULL extends Node_Concrete {
16: /* package */Node_NULL() {
17: super ("");
18: }
19:
20: /** Node_NULL's are equal to no null nodes; strictly speaking,
21: * this incorrect but suits our purposes. really want an isNull
22: * method on Node but that's too much surgery. */
23:
24: public boolean equals(Object other) {
25: return other instanceof Node_NULL;
26: }
27:
28: public Object visitWith(NodeVisitor v) {
29: return null;
30: }
31:
32: public String toString() {
33: return "NULL";
34: }
35: }
36:
37: /*
38: * (c) Copyright 2002, 2003, 2004, 2005, 2006, 2007, 2008 Hewlett-Packard Development Company, LP
39: * All rights reserved.
40: *
41: * Redistribution and use in source and binary forms, with or without
42: * modification, are permitted provided that the following conditions
43: * are met:
44: * 1. Redistributions of source code must retain the above copyright
45: * notice, this list of conditions and the following disclaimer.
46: * 2. Redistributions in binary form must reproduce the above copyright
47: * notice, this list of conditions and the following disclaimer in the
48: * documentation and/or other materials provided with the distribution.
49: * 3. The name of the author may not be used to endorse or promote products
50: * derived from this software without specific prior written permission.
51: *
52: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
53: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
54: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
55: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
56: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
57: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
58: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
59: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
60: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
61: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
62: */
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