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1
29
30 package com.caucho.db.sql;
31
32 import com.caucho.log.Log;
33
34 import java.sql.SQLException  ;
35 import java.util.ArrayList ;
36 import java.util.logging.Logger ;
37
38 class EqExpr extends Expr {
39 private static final Logger log = Log.open(EqExpr.class);
40
41 private Expr _left;
42 private Expr _right;
43
44 EqExpr(Expr left, Expr right)
45 {
46 _left = left;
47 _right = right;
48
49 if (left == null || right == null)
50 throw new NullPointerException ();
51
52 if (right instanceof UnboundIdentifierExpr &&
53 ! (left instanceof UnboundIdentifierExpr)) {
54 Expr temp = _right;
55 _right = _left;
56 _left = temp;
57 }
58 }
59
60 protected Expr bind(Query query)
61 throws SQLException
62 {
63 Expr newLeft = _left.bind(query);
64 Expr newRight = _right.bind(query);
65
66 if (newLeft instanceof ColumnExpr &&
67 newLeft.getType().equals(String .class)) {
68 return new StringEqExpr((ColumnExpr) newLeft, newRight);
69 }
70 else if (newRight instanceof ColumnExpr &&
71 newRight.getType().equals(String .class)) {
72 return new StringEqExpr((ColumnExpr) newRight, newLeft);
73 }
74
75 if (_left == newLeft && _right == newRight)
76 return this;
77 else
78 return new EqExpr(newLeft, newRight);
79 }
80
81
84 public IndexExpr getIndexExpr(FromItem item)
85 {
86 if (_left instanceof IdExpr) {
87 IdExpr expr = (IdExpr) _left;
88
89 if (expr.getColumn().getIndex() != null &&
90 item == expr.getFromItem()) {
91 return new IndexExpr(expr, _right);
92 }
93 }
94
95 if (_right instanceof IdExpr) {
96 IdExpr expr = (IdExpr) _right;
97
98 if (expr.getColumn().getIndex() != null &&
99 item == expr.getFromItem()) {
100 return new IndexExpr(expr, _left);
101 }
102 }
103
104 return null;
105 }
106
107
110 public Class getType()
111 {
112 return boolean.class;
113 }
114
115
118 public long cost(ArrayList <FromItem> fromList)
119 {
120 if (_left instanceof UnboundIdentifierExpr &&
121 _right.cost(fromList) == 0) {
122 UnboundIdentifierExpr id = (UnboundIdentifierExpr) _left;
123
124 return id.lookupCost(fromList);
125 }
126 else if (_right instanceof UnboundIdentifierExpr &&
127 _left.cost(fromList) == 0) {
128 UnboundIdentifierExpr id = (UnboundIdentifierExpr) _right;
129
130 return id.lookupCost(fromList);
131 }
132 else {
133 return subCost(fromList);
134 }
135 }
136
137
140 public long subCost(ArrayList <FromItem> fromList)
141 {
142 return _left.subCost(fromList) + _right.subCost(fromList);
143 }
144
145
148 public boolean isNull(QueryContext context)
149 throws SQLException
150 {
151 return (_left.isNull(context) || _right.isNull(context));
152 }
153
154
157 public int evalBoolean(QueryContext context)
158 throws SQLException
159 {
160 if (_left.isNull(context) || _right.isNull(context))
161 return UNKNOWN;
162
163 if (_left.isLong() && _right.isLong()) {
164 if (_left.evalLong(context) == _right.evalLong(context))
165 return TRUE;
166 else
167 return FALSE;
168 }
169 else if (_left.isDouble() && _right.isDouble()) {
170 if (_left.evalDouble(context) == _right.evalDouble(context))
171 return TRUE;
172 else
173 return FALSE;
174 }
175 else {
176 String leftValue = _left.evalString(context);
177 String rightValue = _right.evalString(context);
178
179 if (leftValue == rightValue || leftValue.equals(rightValue))
180 return TRUE;
181 else
182 return FALSE;
183 }
184 }
185
186 public String evalString(QueryContext context)
187 throws SQLException
188 {
189 throw new SQLException ("can't convert string to boolean");
190 }
191
192
197 public void evalGroup(QueryContext context)
198 throws SQLException
199 {
200 _left.evalGroup(context);
201 _right.evalGroup(context);
202 }
203
204 public String toString()
205 {
206 return "(" + _left + " = " + _right + ")";
207 }
208 }
209 |
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