1 /***
2 * Redistribution and use of this software and associated documentation
3 * ("Software"), with or without modification, are permitted provided
4 * that the following conditions are met:
5 *
6 * 1. Redistributions of source code must retain copyright
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8 * copy of this document.
9 *
10 * 2. Redistributions in binary form must reproduce the
11 * above copyright notice, this list of conditions and the
12 * following disclaimer in the documentation and/or other
13 * materials provided with the distribution.
14 *
15 * 3. The name "Exolab" must not be used to endorse or promote
16 * products derived from this Software without prior written
17 * permission of Exoffice Technologies. For written permission,
18 * please contact info@exolab.org.
19 *
20 * 4. Products derived from this Software may not be called "Exolab"
21 * nor may "Exolab" appear in their names without prior written
22 * permission of Exoffice Technologies. Exolab is a registered
23 * trademark of Exoffice Technologies.
24 *
25 * 5. Due credit should be given to the Exolab Project
26 * (http://www.exolab.org/).
27 *
28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Copyright 2000-2001,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
42 */
43
44 package org.exolab.jms.selector;
45
46 import java.util.HashSet;
47
48 import org.exolab.jms.selector.parser.SelectorTokenTypes;
49
50
51 /***
52 * Default implementation of {@link ExpressionFactory}
53 *
54 * @version $Revision: 1.1 $ $Date: 2004/11/26 01:50:44 $
55 * @author <a href="mailto:tma@netspacce.net.au">Tim Anderson</a>
56 * @see ExpressionFactory
57 * @see SelectorTokenTypes
58 */
59 public final class DefaultExpressionFactory implements ExpressionFactory {
60
61 /***
62 * Create a binary operator expression
63 *
64 * @param operator the operator token type from SelectorTokenTypes
65 * @param left the left-hand side of the binary expression
66 * @param right the right-hand side of the binary expression
67 * @return a new binary expression
68 * @throws SelectorException if the operator is not a valid binary operator
69 */
70 public Expression binaryOperator(final int operator, final Expression left,
71 final Expression right)
72 throws SelectorException {
73
74 Expression result = null;
75 switch (operator) {
76 case SelectorTokenTypes.LITERAL_and:
77 result = new And(left, right);
78 break;
79 case SelectorTokenTypes.LITERAL_or:
80 result = new Or(left, right);
81 break;
82 case SelectorTokenTypes.EQUAL:
83 result = new Equal(left, right);
84 break;
85 case SelectorTokenTypes.NOT_EQUAL:
86 result = new NotEqual(left, right);
87 break;
88 case SelectorTokenTypes.LT:
89 result = new Less(left, right);
90 break;
91 case SelectorTokenTypes.GT:
92 result = new Greater(left, right);
93 break;
94 case SelectorTokenTypes.LE:
95 result = new LessEqual(left, right);
96 break;
97 case SelectorTokenTypes.GE:
98 result = new GreaterEqual(left, right);
99 break;
100 case SelectorTokenTypes.PLUS:
101 result = new Add(left, right);
102 break;
103 case SelectorTokenTypes.MINUS:
104 result = new Subtract(left, right);
105 break;
106 case SelectorTokenTypes.MULTIPLY:
107 result = new Multiply(left, right);
108 break;
109 case SelectorTokenTypes.DIVIDE:
110 result = new Divide(left, right);
111 break;
112 default:
113 throw new SelectorException("Unknown binary operator type: "
114 + operator);
115 }
116 return result;
117 }
118
119 /***
120 * Create an unary operator expression
121 *
122 * @param operator the operator token type from SelectorTokenTypes
123 * @param operand the expression to apply the operator to
124 * @return a new unary expression
125 * @throws SelectorException if the operator is not a valid unary operator
126 */
127 public Expression unaryOperator(final int operator,
128 final Expression operand)
129 throws SelectorException {
130 Expression result = null;
131 switch (operator) {
132 case SelectorTokenTypes.LITERAL_not:
133 result = new Not(operand);
134 break;
135 case SelectorTokenTypes.UNARY_MINUS:
136 result = new UnaryMinus(operand);
137 break;
138 default:
139 throw new SelectorException("Unknown unary operator type: "
140 + operator);
141 }
142 return result;
143 }
144
145 /***
146 * Create an identifier expression
147 *
148 * @param name the name of the identifier
149 * @return a new identifier expression
150 * @throws SelectorException is name is not a valid identifier
151 */
152 public Expression identifier(final String name) throws SelectorException {
153 return new Identifier(name);
154 }
155
156 /***
157 * Create an 'is null' expression
158 *
159 * @param identifier the identifer expression to apply the 'is null' test
160 * @return an 'is null' expression
161 * @throws SelectorException for any error
162 */
163 public Expression isNull(final Expression identifier)
164 throws SelectorException {
165 return new IsExpression((Identifier) identifier);
166 }
167
168 /***
169 * Create a 'like' expression
170 *
171 * @param identifier the identifer to apply the 'like' test to
172 * @param pattern the search pattern
173 * @param escape the escape character. This may be null
174 * @return a new 'like' expression
175 * @throws SelectorException if the pattern or escape is invalid
176 */
177 public Expression like(final Expression identifier, final String pattern,
178 final String escape) throws SelectorException {
179 return new LikeExpression((Identifier) identifier, pattern, escape);
180 }
181
182 /***
183 * Create a 'between' expression that returns the result of:<br/>
184 * <code>num1 >= num2 and num1 <= num3</code>
185 * when evaluated
186 *
187 * @param num1 an arithmethic expression
188 * @param num2 an arithmethic expression
189 * @param num3 an arithmethic expression
190 * @return a new 'between' expression
191 * @throws SelectorException for any error
192 */
193 public Expression between(final Expression num1, final Expression num2,
194 final Expression num3) throws SelectorException {
195 return new BetweenExpression(num1, num2, num3);
196 }
197
198 /***
199 * Create an 'in' expression
200 *
201 * @param identifier string identifer to apply the 'in' test to
202 * @param set the set of string values to compare against
203 * @return a new 'in' expression
204 * @throws SelectorException for any error
205 */
206 public Expression in(final Expression identifier, final HashSet set)
207 throws SelectorException {
208 return new InExpression((Identifier) identifier, set);
209 }
210
211 /***
212 * Create a literal expression
213 *
214 * @param type the operator token type from SelectorTokenTypes
215 * @param text the literal text
216 * @return a new literal expression
217 * @throws SelectorException if type is not a valid literal type
218 */
219 public Expression literal(final int type, final String text)
220 throws SelectorException {
221 Expression result = null;
222 switch (type) {
223 case SelectorTokenTypes.NUM_FLOAT:
224 result = Literal.approxNumericLiteral(text);
225 break;
226 case SelectorTokenTypes.NUM_INT:
227 result = Literal.exactNumericLiteral(text);
228 break;
229 case SelectorTokenTypes.STRING_LITERAL:
230 result = Literal.stringLiteral(text);
231 break;
232 case SelectorTokenTypes.LITERAL_true:
233 result = Literal.booleanLiteral(true);
234 break;
235 case SelectorTokenTypes.LITERAL_false:
236 result = Literal.booleanLiteral(false);
237 break;
238 default:
239 throw new SelectorException("Unknown literal type: " + type);
240 }
241
242 return result;
243 }
244
245 }