01: /*
02: * $Header: /export/home/cvsroot/MyPersonalizerRepository/MyPersonalizer/Subsystems/Kernel/Sources/es/udc/mypersonalizer/kernel/model/query/ast/expr/BinaryExpression.java,v 1.1.1.1 2004/03/25 12:08:37 fbellas Exp $
03: * $Revision: 1.1.1.1 $
04: * $Date: 2004/03/25 12:08:37 $
05: *
06: * =============================================================================
07: *
08: * Copyright (c) 2003, The MyPersonalizer Development Group
09: * (http://www.tic.udc.es/~fbellas/mypersonalizer/index.html) at
10: * University Of A Coruņa
11: * All rights reserved.
12: *
13: * Redistribution and use in source and binary forms, with or without
14: * modification, are permitted provided that the following conditions are met:
15: *
16: * - Redistributions of source code must retain the above copyright notice,
17: * this list of conditions and the following disclaimer.
18: *
19: * - Redistributions in binary form must reproduce the above copyright notice,
20: * this list of conditions and the following disclaimer in the documentation
21: * and/or other materials provided with the distribution.
22: *
23: * - Neither the name of the University Of A Coruņa nor the names of its
24: * contributors may be used to endorse or promote products derived from
25: * this software without specific prior written permission.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
28: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30: * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
31: * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37: * POSSIBILITY OF SUCH DAMAGE.
38: *
39: */
40: package es.udc.mypersonalizer.kernel.model.query.ast.expr;
41:
42: /**
43: * Interface for binary expressions.
44: * <p>
45: * Binary are defined by a two operands (the <em>left-hand side</em>, or
46: * <code>LHS</code>, and the <em>right-hand side</em>, or <code>RHS</code>)
47: * and an operator. The order of the operands <em>might</em> be significant. In
48: * such case, the <code>LHS</code> must be evaluated first.
49: * <p>
50: * This interface defines the methods for accessign the operands. The operator
51: * is defined by the class of the concrete implementation (i.e. it is not
52: * represented by any attribute). This allows for easy visitor-based
53: * traversals of expressions.
54: *
55: * @author Abel Muinho
56: * @since 1.0
57: */
58: public interface BinaryExpression extends Expression {
59:
60: /**
61: * Obtains the left-hand side operator of the expression.
62: * @return the LHS operand.
63: */
64: public Expression getLHS();
65:
66: /**
67: * Sets the left-hand side operator of the expression.
68: * @param e the LHS operand.
69: * @throws IllegalArgumentException if the given operand is not allowed.
70: */
71: public void setLHS(Expression e);
72:
73: /**
74: * Obtains the right-hand side operator of the expression.
75: * @return the RHS operand.
76: */
77: public Expression getRHS();
78:
79: /**
80: * Sets the right-hand side operator of the expression.
81: * @param e the RHS operand.
82: * @throws IllegalArgumentException if the given operand is not allowed.
83: */
84: public void setRHS(Expression e);
85:
86: }
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