1 | /* |
2 | * Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0, |
3 | * and the EPL 1.0 (http://h2database.com/html/license.html). |
4 | * Initial Developer: H2 Group |
5 | */ |
6 | package org.h2.value; |
7 | |
8 | import java.io.InputStream; |
9 | import java.io.Reader; |
10 | import java.math.BigDecimal; |
11 | import java.sql.Date; |
12 | import java.sql.PreparedStatement; |
13 | import java.sql.SQLException; |
14 | import java.sql.Time; |
15 | import java.sql.Timestamp; |
16 | |
17 | import org.h2.message.DbException; |
18 | |
19 | /** |
20 | * Implementation of NULL. NULL is not a regular data type. |
21 | */ |
22 | public class ValueNull extends Value { |
23 | |
24 | /** |
25 | * The main NULL instance. |
26 | */ |
27 | public static final ValueNull INSTANCE = new ValueNull(); |
28 | |
29 | /** |
30 | * This special instance is used as a marker for deleted entries in a map. |
31 | * It should not be used anywhere else. |
32 | */ |
33 | public static final ValueNull DELETED = new ValueNull(); |
34 | |
35 | /** |
36 | * The precision of NULL. |
37 | */ |
38 | private static final int PRECISION = 1; |
39 | |
40 | /** |
41 | * The display size of the textual representation of NULL. |
42 | */ |
43 | private static final int DISPLAY_SIZE = 4; |
44 | |
45 | private ValueNull() { |
46 | // don't allow construction |
47 | } |
48 | |
49 | @Override |
50 | public String getSQL() { |
51 | return "NULL"; |
52 | } |
53 | |
54 | @Override |
55 | public int getType() { |
56 | return Value.NULL; |
57 | } |
58 | |
59 | @Override |
60 | public String getString() { |
61 | return null; |
62 | } |
63 | |
64 | @Override |
65 | public Boolean getBoolean() { |
66 | return null; |
67 | } |
68 | |
69 | @Override |
70 | public Date getDate() { |
71 | return null; |
72 | } |
73 | |
74 | @Override |
75 | public Time getTime() { |
76 | return null; |
77 | } |
78 | |
79 | @Override |
80 | public Timestamp getTimestamp() { |
81 | return null; |
82 | } |
83 | |
84 | @Override |
85 | public byte[] getBytes() { |
86 | return null; |
87 | } |
88 | |
89 | @Override |
90 | public byte getByte() { |
91 | return 0; |
92 | } |
93 | |
94 | @Override |
95 | public short getShort() { |
96 | return 0; |
97 | } |
98 | |
99 | @Override |
100 | public BigDecimal getBigDecimal() { |
101 | return null; |
102 | } |
103 | |
104 | @Override |
105 | public double getDouble() { |
106 | return 0.0; |
107 | } |
108 | |
109 | @Override |
110 | public float getFloat() { |
111 | return 0.0F; |
112 | } |
113 | |
114 | @Override |
115 | public int getInt() { |
116 | return 0; |
117 | } |
118 | |
119 | @Override |
120 | public long getLong() { |
121 | return 0; |
122 | } |
123 | |
124 | @Override |
125 | public InputStream getInputStream() { |
126 | return null; |
127 | } |
128 | |
129 | @Override |
130 | public Reader getReader() { |
131 | return null; |
132 | } |
133 | |
134 | @Override |
135 | public Value convertTo(int type) { |
136 | return this; |
137 | } |
138 | |
139 | @Override |
140 | protected int compareSecure(Value v, CompareMode mode) { |
141 | throw DbException.throwInternalError("compare null"); |
142 | } |
143 | |
144 | @Override |
145 | public long getPrecision() { |
146 | return PRECISION; |
147 | } |
148 | |
149 | @Override |
150 | public int hashCode() { |
151 | return 0; |
152 | } |
153 | |
154 | @Override |
155 | public Object getObject() { |
156 | return null; |
157 | } |
158 | |
159 | @Override |
160 | public void set(PreparedStatement prep, int parameterIndex) |
161 | throws SQLException { |
162 | prep.setNull(parameterIndex, DataType.convertTypeToSQLType(Value.NULL)); |
163 | } |
164 | |
165 | @Override |
166 | public int getDisplaySize() { |
167 | return DISPLAY_SIZE; |
168 | } |
169 | |
170 | @Override |
171 | public boolean equals(Object other) { |
172 | return other == this; |
173 | } |
174 | |
175 | } |