01: /*
02: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
03: *
04: * This file is part of Resin(R) Open Source
05: *
06: * Each copy or derived work must preserve the copyright notice and this
07: * notice unmodified.
08: *
09: * Resin Open Source is free software; you can redistribute it and/or modify
10: * it under the terms of the GNU General Public License as published by
11: * the Free Software Foundation; either version 2 of the License, or
12: * (at your option) any later version.
13: *
14: * Resin Open Source is distributed in the hope that it will be useful,
15: * but WITHOUT ANY WARRANTY; without even the implied warranty of
16: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17: * of NON-INFRINGEMENT. See the GNU General Public License for more
18: * details.
19: *
20: * You should have received a copy of the GNU General Public License
21: * along with Resin Open Source; if not, write to the
22: * Free SoftwareFoundation, Inc.
23: * 59 Temple Place, Suite 330
24: * Boston, MA 02111-1307 USA
25: *
26: * @author Scott Ferguson
27: */
28:
29: package com.caucho.db.sql;
30:
31: import com.caucho.log.Log;
32:
33: import java.sql.SQLException;
34: import java.util.ArrayList;
35: import java.util.logging.Logger;
36:
37: class StringEqExpr extends Expr {
38: private static final Logger log = Log.open(StringEqExpr.class);
39:
40: private ColumnExpr _column;
41: private Expr _right;
42:
43: StringEqExpr(ColumnExpr left, Expr right) {
44: _column = left;
45: _right = right;
46: }
47:
48: protected Expr bind(Query query) throws SQLException {
49: throw new UnsupportedOperationException();
50: }
51:
52: /**
53: * Returns the cost based on the given FromList.
54: */
55: public long subCost(ArrayList<FromItem> fromList) {
56: return _column.subCost(fromList) + _right.subCost(fromList);
57: }
58:
59: /**
60: * Returns the type of the expression.
61: */
62: public Class getType() {
63: return boolean.class;
64: }
65:
66: /**
67: * Returns true for a null value.
68: */
69: public boolean isNull(QueryContext context) throws SQLException {
70: return _column.isNull(context);
71: }
72:
73: /**
74: * Evaluates the expression as a boolean.
75: */
76: public int evalBoolean(QueryContext context) throws SQLException {
77: if (_right.isNull(context))
78: return UNKNOWN;
79: else if (_column.isNull(context))
80: return UNKNOWN;
81:
82: if (_column.evalEqual(context, _right.evalString(context)))
83: return TRUE;
84: else
85: return FALSE;
86: }
87:
88: public String evalString(QueryContext context) throws SQLException {
89: throw new SQLException("can't convert string to boolean");
90: }
91:
92: public String toString() {
93: return "(" + _column + " = " + _right + ")";
94: }
95: }
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