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1 /* 2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/expression/jexl/JexlExpression.java,v 1.9 2002/07/22 14:34:09 jstrachan Exp $ 3 * $Revision: 1.9 $ 4 * $Date: 2002/07/22 14:34:09 $ 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: JexlExpression.java,v 1.9 2002/07/22 14:34:09 jstrachan Exp $ 61 */ 62 63 package org.apache.commons.jelly.expression.jexl; 64 65 import java.util.Map; 66 import java.util.Set; 67 import java.util.Collection; 68 69 import org.apache.commons.jelly.JellyContext; 70 import org.apache.commons.jelly.expression.ExpressionSupport; 71 72 import org.apache.commons.jexl.Expression; 73 import org.apache.commons.jexl.JexlContext; 74 75 import org.apache.commons.logging.Log; 76 import org.apache.commons.logging.LogFactory; 77 78 /*** 79 * Represents a <a href="http://jakarta.apache.org/commons/jexl.html">Jexl</a> 80 * expression which fully supports the Expression Language in JSTL and JSP 81 * along with some extra features like object method invocation. 82 * 83 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> 84 * @version $Revision: 1.9 $ 85 */ 86 87 public class JexlExpression extends ExpressionSupport { 88 89 /*** The Log to which logging calls will be made. */ 90 private static final Log log = LogFactory.getLog(JexlExpression.class); 91 92 /*** The Jexl expression object */ 93 private Expression expression; 94 95 public JexlExpression(Expression expression) { 96 this.expression = expression; 97 } 98 99 // Expression interface 100 //------------------------------------------------------------------------- 101 public Object evaluate(JellyContext context) { 102 try { 103 JexlContext jexlContext = new JellyJexlContext( context ); 104 if (log.isDebugEnabled()) { 105 log.debug("Evaluating EL: " + expression); 106 } 107 return expression.evaluate(jexlContext); 108 } 109 catch (Exception e) { 110 log.warn("Caught exception evaluating: " + expression + ". Reason: " + e, e); 111 return null; 112 } 113 } 114 } 115 116 class JellyJexlContext implements JexlContext { 117 118 private Map vars; 119 120 JellyJexlContext(JellyContext context) { 121 this.vars = new JellyMap( context ); 122 } 123 124 public void setVars(Map vars) { 125 this.vars.clear(); 126 this.vars.putAll( vars ); 127 } 128 129 public Map getVars() { 130 return this.vars; 131 } 132 } 133 134 135 class JellyMap implements Map { 136 137 private JellyContext context; 138 139 JellyMap(JellyContext context) { 140 this.context = context; 141 } 142 143 public Object get(Object key) { 144 return context.findVariable( (String) key ); 145 } 146 147 public void clear() { 148 // not implemented 149 } 150 151 public boolean containsKey(Object key) { 152 return ( get( key ) != null ); 153 } 154 155 public boolean containsValue(Object value) { 156 return false; 157 } 158 159 public Set entrySet() { 160 return null; 161 } 162 163 public boolean isEmpty() { 164 return false; 165 } 166 167 public Set keySet() { 168 return null; 169 } 170 171 public Object put(Object key, Object value) { 172 return null; 173 } 174 175 public void putAll(Map t) { 176 // not implemented 177 } 178 179 public Object remove(Object key) { 180 return null; 181 } 182 183 public int size() { 184 return -1; 185 } 186 187 public Collection values() { 188 return null; 189 } 190 }

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