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1 /* 2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/expression/jexl/JexlExpressionFactory.java,v 1.9 2002/08/12 10:28:51 jstrachan Exp $ 3 * $Revision: 1.9 $ 4 * $Date: 2002/08/12 10:28:51 $ 5 * 6 * ==================================================================== 7 * 8 * The Apache Software License, Version 1.1 9 * 10 * Copyright (c) 1999-2002 The Apache Software Foundation. All rights 11 * reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in 22 * the documentation and/or other materials provided with the 23 * distribution. 24 * 25 * 3. The end-user documentation included with the redistribution, if 26 * any, must include the following acknowlegement: 27 * "This product includes software developed by the 28 * Apache Software Foundation (http://www.apache.org/)." 29 * Alternately, this acknowlegement may appear in the software itself, 30 * if and wherever such third-party acknowlegements normally appear. 31 * 32 * 4. The names "The Jakarta Project", "Commons", and "Apache Software 33 * Foundation" must not be used to endorse or promote products derived 34 * from this software without prior written permission. For written 35 * permission, please contact apache@apache.org. 36 * 37 * 5. Products derived from this software may not be called "Apache" 38 * nor may "Apache" appear in their names without prior written 39 * permission of the Apache Group. 40 * 41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 52 * SUCH DAMAGE. 53 * ==================================================================== 54 * 55 * This software consists of voluntary contributions made by many 56 * individuals on behalf of the Apache Software Foundation. For more 57 * information on the Apache Software Foundation, please see 58 * <http://www.apache.org/>;. 59 * 60 * $Id: JexlExpressionFactory.java,v 1.9 2002/08/12 10:28:51 jstrachan Exp $ 61 */ 62 63 package org.apache.commons.jelly.expression.jexl; 64 65 import org.apache.commons.jelly.JellyContext; 66 import org.apache.commons.jelly.expression.Expression; 67 import org.apache.commons.jelly.expression.ExpressionSupport; 68 import org.apache.commons.jelly.expression.ExpressionFactory; 69 70 //import org.apache.commons.jexl.resolver.FlatResolver; 71 72 /*** 73 * Represents a factory of <a href="http://jakarta.apache.org/commons/jexl.html">Jexl</a> 74 * expression which fully supports the Expression Language in JSTL and JSP. 75 * In addition this ExpressionFactory can also support Ant style variable 76 * names, where '.' is used inside variable names. 77 * 78 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> 79 * @version $Revision: 1.9 $ 80 */ 81 82 public class JexlExpressionFactory implements ExpressionFactory { 83 84 /*** whether we should allow Ant-style expresssions, using dots as part of variable name */ 85 private boolean supportAntVariables = true; 86 87 // ExpressionFactory interface 88 //------------------------------------------------------------------------- 89 public Expression createExpression(final String text) throws Exception { 90 /* 91 92 org.apache.commons.jexl.Expression expr = 93 org.apache.commons.jexl.ExpressionFactory.createExpression(text); 94 95 if ( isSupportAntVariables() ) { 96 expr.addPostResolver(new FlatResolver()); 97 } 98 99 return new JexlExpression( expr ); 100 */ 101 102 final Expression jexlExpression = new JexlExpression( 103 org.apache.commons.jexl.ExpressionFactory.createExpression(text) 104 ); 105 106 if ( isSupportAntVariables() && isValidAntVariableName(text) ) { 107 ExpressionSupport expr = new ExpressionSupport() { 108 public Object evaluate(JellyContext context) { 109 Object answer = jexlExpression.evaluate(context); 110 111 if ( answer == null ) { 112 answer = context.getVariable(text); 113 } 114 115 return answer; 116 } 117 }; 118 119 return expr; 120 } 121 return jexlExpression; 122 } 123 124 // Properties 125 //------------------------------------------------------------------------- 126 127 /*** 128 * @return whether we should allow Ant-style expresssions, using dots as 129 * part of variable name 130 */ 131 public boolean isSupportAntVariables() { 132 return supportAntVariables; 133 } 134 135 /*** 136 * Sets whether we should allow Ant-style expresssions, using dots as 137 * part of variable name 138 */ 139 public void setSupportAntVariables(boolean supportAntVariables) { 140 this.supportAntVariables = supportAntVariables; 141 } 142 143 // Implementation methods 144 //------------------------------------------------------------------------- 145 146 /*** 147 * @return true if the given string is a valid Ant variable name, 148 * typically thats alphanumeric text with '.' etc. 149 */ 150 protected boolean isValidAntVariableName(String text) { 151 char[] chars = text.toCharArray(); 152 for (int i = 0, size = chars.length; i < size; i++ ) { 153 char ch = chars[i]; 154 // could maybe be a bit more restrictive... 155 if ( Character.isWhitespace(ch) || ch == '[' ) { 156 return false; 157 } 158 } 159 return true; 160 } 161 162 }

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