1 package org.drools.semantics.java;
2
3 /*
4 $Id: ExprAnalyzer.java,v 1.6 2003/03/25 19:47:29 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 antlr.RecognitionException;
50 import antlr.TokenStreamException;
51 import antlr.collections.AST;
52 import org.drools.rule.Declaration;
53 import org.drools.semantics.java.parser.JavaLexer;
54 import org.drools.semantics.java.parser.JavaRecognizer;
55 import org.drools.semantics.java.parser.JavaTokenTypes;
56 import org.drools.semantics.java.parser.JavaTreeParser;
57
58 import java.io.StringReader;
59 import java.util.HashSet;
60 import java.util.Iterator;
61 import java.util.Set;
62
63 /*** Expression analyzer.
64 *
65 * @author <a href="mailto:bob@eng.werken.com">bob mcwhirter</a>
66 *
67 * @version $Id: ExprAnalyzer.java,v 1.6 2003/03/25 19:47:29 tdiesler Exp $
68 */
69 public class ExprAnalyzer
70 {
71 // ------------------------------------------------------------
72 // Constructors
73 // ------------------------------------------------------------
74
75 /*** Construct.
76 */
77 public ExprAnalyzer()
78 {
79 // intentionally left blank.
80 }
81
82 // ------------------------------------------------------------
83 // Instance methods
84 // ------------------------------------------------------------
85
86 /*** Analyze an expression.
87 *
88 * @param expr The expression to analyze.
89 * @param availDecls Total set of declarations available.
90 *
91 * @return The array of declarations used by the expression.
92 *
93 * @throws TokenStreamException If an error occurs in the lexer.
94 * @throws RecognitionException If an error occurs in the parser.
95 * @throws MissingDeclarationException If the expression requires
96 * a declaration not present in the available declarations.
97 */
98 public Declaration[] analyze(String expr,
99 Declaration[] availDecls)
100 throws TokenStreamException, RecognitionException, MissingDeclarationException
101 {
102 JavaLexer lexer = new JavaLexer( new StringReader( expr ) );
103 JavaRecognizer parser = new JavaRecognizer( lexer );
104
105 parser.ruleCondition();
106
107 AST ast = parser.getAST();
108
109 return analyze( expr,
110 availDecls,
111 ast );
112 }
113
114 /*** Analyze an expression.
115 *
116 * @param expr The expression to analyze.
117 * @param availDecls Total set of declarations available.
118 * @param ast The AST for the expression.
119 *
120 * @return The array of declarations used by the expression.
121 *
122 * @throws RecognitionException If an error occurs in the parser.
123 * @throws MissingDeclarationException If the expression requires
124 */
125 private Declaration[] analyze(String expr,
126 Declaration[] availDecls,
127 AST ast) throws RecognitionException, MissingDeclarationException
128 {
129 JavaTreeParser treeParser = new JavaTreeParser();
130
131 treeParser.init();
132
133 treeParser.exprCondition( ast );
134
135 Set availDeclSet = new HashSet();
136
137 for ( int i = 0 ; i < availDecls.length ; ++i )
138 {
139 availDeclSet.add( availDecls[i] );
140 }
141
142 Set refs = new HashSet( treeParser.getVariableReferences() );
143
144 Set declSet = new HashSet();
145
146 Iterator declIter = availDeclSet.iterator();
147 Declaration eachDecl = null;
148
149 while ( declIter.hasNext() )
150 {
151 eachDecl = (Declaration) declIter.next();
152
153 if ( refs.contains( eachDecl.getIdentifier() ) )
154 {
155 declSet.add( eachDecl );
156 declIter.remove();
157 refs.remove( eachDecl.getIdentifier() );
158 }
159 }
160
161 /*
162 if ( ! refs.isEmpty() )
163 {
164 throw new MissingDeclarationException( expr,
165 (String) refs.iterator().next() );
166 }
167 */
168
169 Declaration[] decls = new Declaration[ declSet.size() ];
170
171 declIter = declSet.iterator();
172 eachDecl = null;
173
174 int i = 0;
175
176 while ( declIter.hasNext() )
177 {
178 decls[ i++ ] = (Declaration) declIter.next();
179 }
180
181 return decls;
182 }
183 }
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