1 package org.drools.semantics.python;
2
3 /*
4 $Id: Eval.java,v 1.6 2003/03/25 19:47:32 tdiesler Exp $
5
6 Copyright 2002 (C) The Werken Company. All Rights Reserved.
7
8 Redistribution and use of this software and associated documentation
9 ("Software"), with or without modification, are permitted provided
10 that the following conditions are met:
11
12 1. Redistributions of source code must retain copyright
13 statements and notices. Redistributions must also contain a
14 copy of this document.
15
16 2. Redistributions in binary form must reproduce the
17 above copyright notice, this list of conditions and the
18 following disclaimer in the documentation and/or other
19 materials provided with the distribution.
20
21 3. The name "drools" must not be used to endorse or promote
22 products derived from this Software without prior written
23 permission of The Werken Company. For written permission,
24 please contact bob@werken.com.
25
26 4. Products derived from this Software may not be called "drools"
27 nor may "drools" appear in their names without prior written
28 permission of The Werken Company. "drools" is a registered
29 trademark of The Werken Company.
30
31 5. Due credit should be given to The Werken Company.
32 (http://drools.werken.com/).
33
34 THIS SOFTWARE IS PROVIDED BY THE WERKEN COMPANY AND CONTRIBUTORS
35 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
36 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
37 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
38 THE WERKEN COMPANY OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
39 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
40 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
41 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
42 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
43 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
44 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
45 OF THE POSSIBILITY OF SUCH DAMAGE.
46
47 */
48
49 import org.drools.rule.Declaration;
50 import org.drools.smf.ConfigurationException;
51 import org.drools.spi.Tuple;
52 import org.python.core.PyDictionary;
53 import org.python.core.PyObject;
54 import org.python.core.__builtin__;
55
56 import java.util.Hashtable;
57
58 /*** Base class for Jython expression-based Python semantic components.
59 *
60 * @see ExprCondition
61 * @see ExprExtractor
62 *
63 * @author <a href="mailto:bob@eng.werken.com">bob mcwhirter</a>
64 * @author <a href="mailto:christiaan@dacelo.nl">Christiaan ten Klooster</a>
65 *
66 * @version $Id: Eval.java,v 1.6 2003/03/25 19:47:32 tdiesler Exp $
67 */
68 public class Eval extends Interp
69 {
70 // ------------------------------------------------------------
71 // Instance members
72 // ------------------------------------------------------------
73
74 /*** Interpreted text. */
75 private String text;
76
77 /*** Required decls. */
78 private Declaration[] decls;
79
80 // ------------------------------------------------------------
81 // Constructors
82 // ------------------------------------------------------------
83
84 /*** Construct.
85 */
86 protected Eval()
87 {
88 // intentionally left blank
89 }
90
91 // ------------------------------------------------------------
92 // Instance methods
93 // ------------------------------------------------------------
94
95 /*** Evaluate.
96 *
97 * @param tuple Tuple containing variable bindings.
98 *
99 * @return The result of evaluation.
100 */
101 public Object evaluate(Tuple tuple)
102 {
103 PyDictionary dict = setUpDictionary( tuple );
104
105 return evaluate( dict );
106 }
107
108 /*** Evaluate.
109 *
110 * @param locals The evaluation dictionary.
111 *
112 * @return The result of evaluation.
113 */
114 protected Object evaluate(PyDictionary locals)
115 {
116 PyDictionary globals = new PyDictionary( new Hashtable() );
117
118 PyObject result = __builtin__.eval( getCode(),
119 locals,
120 globals );
121
122 return result.__tojava__(Object.class);
123 }
124
125
126 /*** Evaluate.
127 *
128 * @return The result of evaluation.
129 */
130 protected Object evaluate()
131 {
132 PyDictionary locals = new PyDictionary( new Hashtable() );
133
134 return evaluate( locals );
135 }
136
137 /*** Set the expression to evaluate.
138 *
139 * @param expr The expression.
140 */
141 public void setExpression(String expr)
142 {
143 setText( expr,
144 "eval" );
145 }
146
147 /*** Return the expression.
148 *
149 * @return The expression.
150 */
151 public String getExpression()
152 {
153 return getText();
154 }
155
156 /*** Retrieve the array of <code>Declaration</code>s required
157 * by this condition to perform its duties.
158 *
159 * @return The array of <code>Declarations</code> expected
160 * on incoming <code>Tuples</code>.
161 */
162 public Declaration[] getRequiredTupleMembers()
163 {
164 return this.decls;
165 }
166
167 /*** Configure.
168 *
169 * @param text Configuration text.
170 * @param availDecls Available declarations.
171 *
172 * @throws ConfigurationException If an error occurs while
173 * attempting to perform configuration.
174 */
175 public void configure(String text,
176 Declaration[] availDecls) throws ConfigurationException
177 {
178 try
179 {
180 setExpression( text );
181
182 ExprAnalyzer analyzer = new ExprAnalyzer();
183
184 this.decls = analyzer.analyze( getNode(),
185 availDecls );
186 }
187 catch (Exception e)
188 {
189 throw new ConfigurationException( e );
190 }
191 }
192 }
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