01: /*
02: * Copyright Aduna (http://www.aduna-software.com/) (c) 1997-2006.
03: *
04: * Licensed under the Aduna BSD-style license.
05: */
06: package org.openrdf.query.algebra;
07:
08: /**
09: * Checks whether the wrapped Query produces any results.
10: */
11: public class Exists extends SubQueryValueOperator {
12:
13: /*--------------*
14: * Constructors *
15: *--------------*/
16:
17: public Exists() {
18: }
19:
20: public Exists(TupleExpr subQuery) {
21: super (subQuery);
22: }
23:
24: /*---------*
25: * Methods *
26: *---------*/
27:
28: public <X extends Exception> void visit(QueryModelVisitor<X> visitor)
29: throws X {
30: visitor.meet(this );
31: }
32:
33: @Override
34: public Exists clone() {
35: return (Exists) super.clone();
36: }
37: }
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