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1 package org.drools.semantics.java; 2 3 /* 4 $Id: Interp.java,v 1.7 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 bsh.EvalError; 50 import bsh.Interpreter; 51 import bsh.NameSpace; 52 import org.drools.rule.Declaration; 53 import org.drools.spi.ObjectType; 54 import org.drools.spi.Tuple; 55 56 import java.util.Iterator; 57 import java.util.Set; 58 59 /*** Base class for BeanShell interpreter-based Java semantic components. 60 * 61 * @see ExprCondition 62 * @see ExprExtractor 63 * @see BlockConsequence 64 * 65 * @author <a href="mailto:bob@eng.werken.com">bob mcwhirter</a> 66 * 67 * @version $Id: Interp.java,v 1.7 2003/03/25 19:47:29 tdiesler Exp $ 68 */ 69 public class Interp 70 { 71 // ------------------------------------------------------------ 72 // Instance members 73 // ------------------------------------------------------------ 74 75 /*** Interpreted text. */ 76 private String text; 77 78 /*** BeanShell interpreter. */ 79 private Interpreter interp; 80 81 // ------------------------------------------------------------ 82 // Constructors 83 // ------------------------------------------------------------ 84 85 /*** Construct. 86 */ 87 protected Interp() 88 { 89 this.interp = new Interpreter(); 90 this.text = null; 91 } 92 93 // ------------------------------------------------------------ 94 // Instance methods 95 // ------------------------------------------------------------ 96 97 /*** Evaluate. 98 * 99 * @param tuple Tuple containing variable bindings. 100 * 101 * @return The result of evaluation. 102 * 103 * @throws EvalError If an error occurs while attempting 104 * to evaluate. 105 */ 106 public Object evaluate(Tuple tuple) throws EvalError 107 { 108 NameSpace ns = setUpNameSpace( tuple ); 109 110 return evaluate( ns ); 111 } 112 113 /*** Evaluate. 114 * 115 * @param ns The evaluation namespace. 116 * 117 * @return The result of evaluation. 118 * 119 * @throws EvalError If an error occurs while attempting 120 * to evaluate. 121 */ 122 protected Object evaluate(NameSpace ns) throws EvalError 123 { 124 return this.interp.eval( getText(), 125 ns ); 126 } 127 128 /*** Retrieve the text to evaluate. 129 * 130 * @return The text to evaluate. 131 */ 132 public String getText() 133 { 134 return this.text; 135 } 136 137 /*** Set the text to evaluate. 138 * 139 * @param text The text. 140 */ 141 protected void setText(String text) 142 { 143 this.text = text; 144 } 145 146 /*** Configure a <code>NameSpace</code> using a <code>Tuple</code> 147 * for variable bindings. 148 * 149 * @param tuple Tuple containing variable bindings. 150 * 151 * @return The namespace 152 * 153 * @throws EvalError If an error occurs while attempting 154 * to bind variables. 155 */ 156 protected NameSpace setUpNameSpace(Tuple tuple) throws EvalError 157 { 158 NameSpace ns = new NameSpace( "" ); 159 160 Set decls = tuple.getDeclarations(); 161 162 Iterator declIter = decls.iterator(); 163 Declaration eachDecl = null; 164 165 ObjectType objectType = null; 166 167 while ( declIter.hasNext() ) 168 { 169 eachDecl = (Declaration) declIter.next(); 170 171 ns.setVariable( eachDecl.getIdentifier(), 172 tuple.get( eachDecl ) ); 173 174 objectType = eachDecl.getObjectType(); 175 176 if ( objectType instanceof ClassObjectType ) 177 { 178 ns.importClass( ((ClassObjectType)objectType).getType().getName() ); 179 } 180 } 181 182 return ns; 183 } 184 }

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