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1 package com.quadcap.sql.types;
2
3
40
41 import java.io.Externalizable  ;
42 import java.io.IOException ;
43 import java.io.ObjectInput ;
44 import java.io.ObjectOutput ;
45
46 import com.quadcap.sql.io.ExternalizeProxy;
47
48 import com.quadcap.util.Debug;
49
50
55 public class ValueNull extends Value implements Externalizable , ExternalizeProxy {
56 boolean collatesLast = false;
57
58 public static ValueNull valueNull = new ValueNull();
59 public static ValueNull valueLastNull = new ValueNull(true);
60
61 public ValueNull() {}
62
63 public ValueNull(boolean collatesLast) {
64 this.collatesLast = collatesLast;
65 }
66
67 public Value binop(int op, Value l) throws ValueException {
68 return l.binop(op, this);
69 }
70
71 public ValueInteger nullCmpVal() {
72 return collatesLast ? ValueInteger.PLUS_ONE : ValueInteger.MINUS_ONE;
73 }
74
75 public ValueInteger valCmpNull() {
76 return collatesLast ? ValueInteger.MINUS_ONE : ValueInteger.PLUS_ONE;
77 }
78
79 Value anyBinOp(int op, Value r) throws ValueException {
80 switch (op) {
81 case Op.COMPARE:
82 return nullCmpVal();
83 case Op.EQ:
84 case Op.GE:
85 case Op.GT:
86 case Op.LE:
87 case Op.LT:
88 case Op.NE:
89 return ValueUnknown.valueUnknown;
90 case Op.PLUS:
91 case Op.MINUS:
92 case Op.TIMES:
93 case Op.DIVIDE:
94 case Op.EXP:
95 return this;
96 default:
97 return ValueUnknown.valueUnknown;
98 }
99 }
100
101 public Value binop(int op, ValueBlob r) throws ValueException {
102 return anyBinOp(op, r);
103 }
104
105 public Value binop(int op, ValueBoolean r) throws ValueException {
106 return anyBinOp(op, r);
107 }
108
109 public Value binop(int op, ValueByte r) throws ValueException {
110 return anyBinOp(op, r);
111 }
112
113 public Value binop(int op, ValueClob r) throws ValueException {
114 return anyBinOp(op, r);
115 }
116
117 public Value binop(int op, ValueDate r) throws ValueException {
118 return anyBinOp(op, r);
119 }
120
121 public Value binop(int op, ValueDefault r) throws ValueException {
122 return anyBinOp(op, r);
123 }
124
125 public Value binop(int op, ValueDouble r) throws ValueException {
126 return anyBinOp(op, r);
127 }
128
129 public Value binop(int op, ValueInteger r) throws ValueException {
130 return anyBinOp(op, r);
131 }
132
133 public Value binop(int op, ValueInterval r) throws ValueException {
134 return anyBinOp(op, r);
135 }
136
137 public Value binop(int op, ValueLong r) throws ValueException {
138 return anyBinOp(op, r);
139 }
140
141 public Value binop(int op, ValueNull r) throws ValueException {
142 return ValueNull.binop(op, this, r);
143 }
144
145 public Value binop(int op, ValueOctets r) throws ValueException {
146 return anyBinOp(op, r);
147 }
148
149 public Value binop(int op, ValuePattern r) throws ValueException {
150 return anyBinOp(op, r);
151 }
152
153 public Value binop(int op, ValueScaledInteger r) throws ValueException {
154 return anyBinOp(op, r);
155 }
156
157 public Value binop(int op, ValueShort r) throws ValueException {
158 return anyBinOp(op, r);
159 }
160
161 public Value binop(int op, ValueString r) throws ValueException {
162 return anyBinOp(op, r);
163 }
164
165 public Value binop(int op, ValueTime r) throws ValueException {
166 return anyBinOp(op, r);
167 }
168
169 public Value binop(int op, ValueTimestamp r) throws ValueException {
170 return anyBinOp(op, r);
171 }
172
173 public Value binop(int op, ValueType r) throws ValueException {
174 return anyBinOp(op, r);
175 }
176
177 public Value binop(int op, ValueUnknown r) throws ValueException {
178 return anyBinOp(op, r);
179 }
180
181 public static final Value binop(int op, ValueNull e, ValueNull f)
182 throws ValueException
183 {
184 switch (op) {
185 case Op.EQ:
186 case Op.GE:
187 case Op.GT:
188 case Op.LE:
189 case Op.LT:
190 case Op.NE:
191 return ValueUnknown.valueUnknown;
192 case Op.PLUS:
193 case Op.MINUS:
194 case Op.TIMES:
195 case Op.DIVIDE:
196 case Op.EXP:
197 return f;
198 case Op.COMPARE:
199 return ValueInteger.ZERO;
200
201 default:
202 return e;
203 }
204 }
205
206 public Value unop(int op) throws ValueException {
207 switch (op) {
208 case Op.NULL:
209 return new ValueBoolean(true);
210 case Op.PLUS:
211 return ValueUnknown.valueUnknown;
212 case Op.MINUS:
213 return ValueUnknown.valueUnknown;
214 default:
215 throw new ValueException("Unary op: " + Op.toString(op) +
216 " not implemented for this type");
217 }
218 }
219
220 public String toString() {
221 return collatesLast ? "lastnull" : "null";
222 }
223
224 public void readExternal(ObjectInput in) throws IOException {
225 collatesLast = in.read() == 1;
226 }
227
228 public void writeExternal(ObjectOutput out)
229 throws IOException
230 {
231 out.write(collatesLast ? 1 : 0);
232 }
233
234 public Object readObject(ObjectInput in)
235 throws IOException , ClassNotFoundException
236 {
237 int cl = in.readByte();
238 ValueNull v = new ValueNull(cl == 1);
239 return v;
240 }
241
242 public void writeObject(ObjectOutput out, Object object)
243 throws IOException
244 {
245 ValueNull v = (ValueNull)object;
246 out.write(v.collatesLast ? 1 : 0);
247 }
248
249 public Object asJavaObject() {
250 return null;
251 }
252
253 public void fromJavaObject(Object obj) throws ValueException {
254 if (obj != null) throw new ValueException("bad type: " + obj);
255 }
256
257 public Value convert(TypeBigInt type) { return this; }
259 public Value convert(TypeBinary type) { return this; }
260 public Value convert(TypeBlob type) { return this; }
261 public Value convert(TypeBoolean type) { return this; }
262 public Value convert(TypeChar type) { return this; }
263 public Value convert(TypeClob type) { return this; }
264 public Value convert(TypeDate type) { return this; }
265 public Value convert(TypeDecimal type) { return this; }
266 public Value convert(TypeInt type) { return this; }
267 public Value convert(TypeInterval type) { return this; }
268 public Value convert(TypeReal type) { return this; }
269 public Value convert(TypeSmallInt type) { return this; }
270 public Value convert(TypeTime type) { return this; }
271 public Value convert(TypeTimestamp type) { return this; }
272 public Value convert(TypeTinyInt type) { return this; }
273 public Value convert(TypeVarBinary type) { return this; }
274 public Value convert(TypeVarChar type) { return this; }
275
276 public Type getType() {
277 return TypeAny.any;
278 }
279
280 public void serializeKey(KeyStream out) throws IOException {
281 out.writeNull(collatesLast);
282 }
283 }
284 |
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