/*
* Copyright 2008 Fedora Commons
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.mulgara.sparql.parser.cst;
/**
* Represents no data in a given position of a query
*
* @created Feb 21, 2008
* @author Paula Gearon
* @copyright © 2008 <a href="http://www.fedora-commons.org/">Fedora Commons</a>
* @licence <a href="{@docRoot}/../LICENCE.txt">Apache License, Version 2.0</a>
*/
public class Nil implements Node {
public static final Nil NIL_NODE = new Nil();
/**
* Private constructor to enforce the singleton
*/
private Nil() {
}
/**
* @see org.mulgara.sparql.parser.cst.Node#getImage()
*/
public String getImage() {
return "()";
}
}