/*
* Copyright Aduna (http://www.aduna-software.com/) (c) 1997-2006.
*
* Licensed under the Aduna BSD-style license.
*/
package org.openrdf.query.algebra;
import java.util.Collections;
import java.util.Set;
/**
* A tuple expression that contains exactly one solution with zero bindings.
*/
public class SingletonSet extends QueryModelNodeBase implements TupleExpr {
public Set<String> getBindingNames() {
return Collections.emptySet();
}
public <X extends Exception> void visit(QueryModelVisitor<X> visitor)
throws X
{
visitor.meet(this);
}
@Override
public SingletonSet clone() {
return (SingletonSet)super.clone();
}
}