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1
5 package org.h2.expression;
6
7 import java.sql.SQLException  ;
8
9 import org.h2.engine.Session;
10 import org.h2.index.IndexCondition;
11 import org.h2.message.Message;
12 import org.h2.table.ColumnResolver;
13 import org.h2.table.TableFilter;
14 import org.h2.value.Value;
15 import org.h2.value.ValueBoolean;
16 import org.h2.value.ValueNull;
17
18 public class ValueExpression extends Expression {
19 private Value value;
20
21 public static final ValueExpression NULL = new ValueExpression(ValueNull.INSTANCE);
22
23 public static ValueExpression get(Value v) {
24 if(v == ValueNull.INSTANCE) {
25 return ValueExpression.NULL;
26 }
27 return new ValueExpression(v);
28 }
29
30 private ValueExpression(Value value) {
31 this.value = value;
32 }
33
34 public Value getValue(Session session) {
35 return value;
36 }
37
38 public int getType() {
39 return value.getType();
40 }
41
42 public void createIndexConditions(TableFilter filter) {
43 if(value.getType() == Value.BOOLEAN) {
44 boolean v = ((ValueBoolean)value).getBoolean().booleanValue();
45 if(!v) {
46 filter.addIndexCondition(new IndexCondition(Comparison.FALSE, null, this));
47 }
48 }
49 }
50
51 public void mapColumns(ColumnResolver resolver, int level) throws SQLException {
52 }
53
54 public Expression optimize(Session session) throws SQLException {
55 return this;
56 }
57
58 public boolean isConstant() {
59 return true;
60 }
61
62 public void setEvaluatable(TableFilter tableFilter, boolean b) {
63 }
64
65 public int getScale() {
66 return value.getScale();
67 }
68
69 public long getPrecision() {
70 return value.getPrecision();
71 }
72
73 public String getSQL() {
74 return value.getSQL();
75 }
76
77 public void updateAggregate(Session session) throws SQLException {
78 }
79
80 public boolean isEverything(ExpressionVisitor visitor) {
81 switch(visitor.type) {
82 case ExpressionVisitor.OPTIMIZABLE_MIN_MAX_COUNT_ALL:
83 return true;
84 case ExpressionVisitor.DETERMINISTIC:
85 case ExpressionVisitor.READONLY:
86 return true;
87 case ExpressionVisitor.INDEPENDENT:
88 return true;
89 case ExpressionVisitor.EVALUATABLE:
90 return true;
91 case ExpressionVisitor.SET_MAX_DATA_MODIFICATION_ID:
92 return true;
93 default:
94 throw Message.getInternalError("type="+visitor.type);
95 }
96 }
97
98 public int getCost() {
99 return 0;
100 }
101
102 }
103 |
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