/*
* xtc - The eXTensible Compiler
* Copyright (C) 2004-2007 Robert Grimm
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
package xtc.parser;
/**
* Element to set the semantic value to <code>null</code>.
*
* @author Robert Grimm
* @version $Revision: 1.8 $
*/
public class NullValue extends ValueElement {
/** The canonical null value element. */
public static final NullValue VALUE = new NullValue();
/** Hide the constructor. */
private NullValue() { /* Nothing to do. */ }
public Tag tag() {
return Tag.NULL_VALUE;
}
public int hashCode() {
return 5;
}
public boolean equals(Object o) {
if (VALUE == o) return true;
return (o instanceof NullValue);
}
}