01: /*
02: * <copyright>
03: *
04: * Copyright 1997-2004 BBNT Solutions, LLC
05: * under sponsorship of the Defense Advanced Research Projects
06: * Agency (DARPA).
07: *
08: * You can redistribute this software and/or modify it under the
09: * terms of the Cougaar Open Source License as published on the
10: * Cougaar Open Source Website (www.cougaar.org).
11: *
12: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
13: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
14: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
15: * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
16: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
17: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
18: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
22: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: *
24: * </copyright>
25: */
26:
27: package org.cougaar.lib.contract.lang.op.logical;
28:
29: import java.util.*;
30:
31: import org.cougaar.lib.contract.lang.*;
32: import org.cougaar.lib.contract.lang.op.OpCodes;
33:
34: /**
35: * "false" <code>Op</code> -- simply returns false
36: */
37: public final class FalseOp extends OpImpl {
38:
39: public static final FalseOp singleInstance = new FalseOp();
40:
41: private FalseOp() {
42: }
43:
44: public final int getID() {
45: return OpCodes.FALSE_ID;
46: }
47:
48: public final Op parse(final OpParser p) throws ParseException {
49: Op u1 = p.nextOp();
50: if (u1 != null) {
51: throw new ParseException("\"" + OpCodes.FALSE_NAME
52: + "\" expecting zero arguments, but given "
53: + u1.getClass().toString());
54: }
55: return this ;
56: }
57:
58: public final boolean execute(final Object o) {
59: return false;
60: }
61:
62: public final void accept(TreeVisitor visitor) {
63: // (false)
64: visitor.visitWord(OpCodes.FALSE_NAME);
65: visitor.visitEnd();
66: }
67: }
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