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1 package org.drools.semantics.java; 2 3 /* 4 $Id: Expr.java,v 1.6 2002/08/19 04:30:49 bob 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 52 /*** Base class for expression-based Java semantic components. 53 * 54 * @see ExprCondition 55 * @see ExprExtractor 56 * 57 * @author <a href="mailto:bob@eng.werken.com">bob mcwhirter</a> 58 * 59 * @version $Id: Expr.java,v 1.6 2002/08/19 04:30:49 bob Exp $ 60 */ 61 public class Expr extends Interp 62 { 63 // ------------------------------------------------------------ 64 // Constants 65 // ------------------------------------------------------------ 66 67 /*** Empty declaration array. */ 68 private static final Declaration[] EMPTY_DECLS = new Declaration[0]; 69 70 // ------------------------------------------------------------ 71 // Instance members 72 // ------------------------------------------------------------ 73 74 /*** Required declarations. */ 75 private Declaration[] requiredDecls; 76 77 // ------------------------------------------------------------ 78 // Constants 79 // ------------------------------------------------------------ 80 81 /*** Construct. 82 */ 83 protected Expr() 84 { 85 this.requiredDecls = EMPTY_DECLS; 86 } 87 88 /*** Construct. 89 * 90 * @param expr The expression. 91 * @param availDecls The available declarations. 92 * 93 * @throws ConfigurationException If an error occurs while 94 * attempting to perform configuration. 95 */ 96 protected Expr(String expr, 97 Declaration[] availDecls) throws ConfigurationException 98 { 99 configure( expr, 100 availDecls ); 101 } 102 103 // ------------------------------------------------------------ 104 // Constants 105 // ------------------------------------------------------------ 106 107 /*** Retrieve the expression. 108 * 109 * @return The expression. 110 */ 111 public String getExpression() 112 { 113 return getText(); 114 } 115 116 /*** Set the expression. 117 * 118 * @param expr The expression. 119 */ 120 protected void setExpression(String expr) 121 { 122 setText( expr ); 123 } 124 125 /*** Configure/parse the expression. 126 * 127 * @param expr The expression. 128 * @param decls All available declarations. 129 * 130 * @throws ConfigurationException If an error occurs while 131 * attempting to configure/parse the expression. 132 */ 133 public void configure(String expr, 134 Declaration[] decls) throws ConfigurationException 135 { 136 ExprAnalyzer analyzer = new ExprAnalyzer(); 137 138 try 139 { 140 this.requiredDecls = analyzer.analyze( expr, 141 decls ); 142 } 143 catch (Exception e) 144 { 145 throw new ConfigurationException( e ); 146 } 147 148 setExpression( expr ); 149 } 150 151 /*** Retrieve the <code>Declaration</code>s required for 152 * evaluating the expression. 153 * 154 * @return The required declarations. 155 */ 156 public Declaration[] getRequiredTupleMembers() 157 { 158 return this.requiredDecls; 159 } 160 }

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