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1
5 package org.h2.index;
6
7 import java.sql.SQLException  ;
8
9 import org.h2.engine.Session;
10 import org.h2.expression.Comparison;
11 import org.h2.expression.Expression;
12 import org.h2.expression.ExpressionColumn;
13 import org.h2.expression.ExpressionVisitor;
14 import org.h2.message.Message;
15 import org.h2.table.Column;
16 import org.h2.value.Value;
17
18
19
22 public class IndexCondition {
23 public static final int EQUALITY = 1, START = 2, END = 4, RANGE = START | END, ALWAYS_FALSE = 8;
24 private Column column;
25 private Expression expression;
26 private int compareType;
27
28 public IndexCondition(int compareType, ExpressionColumn column, Expression expression) {
29 this.compareType = compareType;
30 this.column = column == null ? null : column.getColumn();
31 this.expression = expression;
32 }
33
34 public Value getCurrentValue(Session session) throws SQLException {
35 return expression.getValue(session);
36 }
37
38 public String getSQL() {
39 if(compareType == Comparison.FALSE) {
40 return "FALSE";
41 }
42 StringBuffer buff = new StringBuffer ();
43 buff.append(column.getSQL());
44 switch(compareType) {
45 case Comparison.EQUAL:
46 buff.append(" = ");
47 break;
48 case Comparison.BIGGER_EQUAL:
49 buff.append(" >= ");
50 break;
51 case Comparison.BIGGER:
52 buff.append(" > ");
53 break;
54 case Comparison.SMALLER_EQUAL:
55 buff.append(" <= ");
56 break;
57 case Comparison.SMALLER:
58 buff.append(" < ");
59 break;
60 default:
61 throw Message.getInternalError("type="+compareType);
62 }
63 buff.append(expression.getSQL());
64 return buff.toString();
65 }
66
67 public int getMask() {
68 switch (compareType) {
69 case Comparison.FALSE:
70 return ALWAYS_FALSE;
71 case Comparison.EQUAL:
72 return EQUALITY;
73 case Comparison.BIGGER_EQUAL:
74 case Comparison.BIGGER:
75 return START;
76 case Comparison.SMALLER_EQUAL:
77 case Comparison.SMALLER:
78 return END;
79 default:
80 throw Message.getInternalError("type=" + compareType);
81 }
82 }
83
84 public boolean isAlwaysFalse() {
85 return compareType == Comparison.FALSE;
86 }
87
88 public boolean isStart() {
89 switch (compareType) {
90 case Comparison.EQUAL:
91 case Comparison.BIGGER_EQUAL:
92 case Comparison.BIGGER:
93 return true;
94 }
95 return false;
96 }
97
98 public boolean isEnd() {
99 switch (compareType) {
100 case Comparison.EQUAL:
101 case Comparison.SMALLER_EQUAL:
102 case Comparison.SMALLER:
103 return true;
104 }
105 return false;
106 }
107
108 public Column getColumn() {
109 return column;
110 }
111
112 public boolean isEvaluatable() {
113 return expression.isEverything(ExpressionVisitor.EVALUATABLE);
114 }
115
116 }
117 |
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