01: /* Copyright (C) 2004 - 2007 db4objects Inc. http://www.db4o.com
02:
03: This file is part of the db4o open source object database.
04:
05: db4o is free software; you can redistribute it and/or modify it under
06: the terms of version 2 of the GNU General Public License as published
07: by the Free Software Foundation and as clarified by db4objects' GPL
08: interpretation policy, available at
09: http://www.db4o.com/about/company/legalpolicies/gplinterpretation/
10: Alternatively you can write to db4objects, Inc., 1900 S Norfolk Street,
11: Suite 350, San Mateo, CA 94403, USA.
12:
13: db4o is distributed in the hope that it will be useful, but WITHOUT ANY
14: WARRANTY; without even the implied warranty of MERCHANTABILITY or
15: FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16: for more details.
17:
18: You should have received a copy of the GNU General Public License along
19: with this program; if not, write to the Free Software Foundation, Inc.,
20: 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
21: package com.db4o.nativequery.expr;
22:
23: import com.db4o.nativequery.expr.cmp.ComparisonOperator;
24: import com.db4o.nativequery.expr.cmp.operand.*;
25:
26: public class ComparisonExpression implements Expression {
27: private FieldValue _left;
28: private ComparisonOperand _right;
29: private ComparisonOperator _op;
30:
31: public ComparisonExpression(FieldValue left,
32: ComparisonOperand right, ComparisonOperator op) {
33: if (left == null || right == null || op == null) {
34: throw new NullPointerException();
35: }
36: this ._left = left;
37: this ._right = right;
38: this ._op = op;
39: }
40:
41: public FieldValue left() {
42: return _left;
43: }
44:
45: public ComparisonOperand right() {
46: return _right;
47: }
48:
49: public ComparisonOperator op() {
50: return _op;
51: }
52:
53: public String toString() {
54: return _left + " " + _op + " " + _right;
55: }
56:
57: public boolean equals(Object other) {
58: if (this == other) {
59: return true;
60: }
61: if (other == null || getClass() != other.getClass()) {
62: return false;
63: }
64: ComparisonExpression casted = (ComparisonExpression) other;
65: return _left.equals(casted._left)
66: && _right.equals(casted._right)
67: && _op.equals(casted._op);
68: }
69:
70: public int hashCode() {
71: return (_left.hashCode() * 29 + _right.hashCode()) * 29
72: + _op.hashCode();
73: }
74:
75: public void accept(ExpressionVisitor visitor) {
76: visitor.visit(this);
77: }
78: }
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