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1 /* 2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/taglibs/beanshell/src/java/org/apache/commons/jelly/tags/beanshell/BeanShellExpressionFactory.java,v 1.1 2002/05/21 07:58:55 jstrachan Exp $ 3 * $Revision: 1.1 $ 4 * $Date: 2002/05/21 07:58:55 $ 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: BeanShellExpressionFactory.java,v 1.1 2002/05/21 07:58:55 jstrachan Exp $ 61 */ 62 63 package org.apache.commons.jelly.tags.define; 64 65 import java.lang.reflect.Method; 66 import java.util.HashMap; 67 import java.util.Map; 68 69 import org.apache.commons.jelly.JellyException; 70 import org.apache.commons.jelly.MissingAttributeException; 71 import org.apache.commons.jelly.Tag; 72 import org.apache.commons.jelly.XMLOutput; 73 import org.apache.commons.jelly.impl.Attribute; 74 import org.apache.commons.jelly.impl.DynamicBeanTag; 75 import org.apache.commons.jelly.impl.TagFactory; 76 77 import org.apache.commons.logging.Log; 78 import org.apache.commons.logging.LogFactory; 79 80 81 /*** 82 * Binds a Java bean to the given named Jelly tag so that the attributes of 83 * the tag set the bean properties.. 84 * 85 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> 86 * @version $Revision: 1.1 $ 87 */ 88 public class BeanTag extends DefineTagSupport { 89 90 /*** The Log to which logging calls will be made. */ 91 private static final Log log = LogFactory.getLog(BeanTag.class); 92 93 /*** An empty Map as I think Collections.EMPTY_MAP is only JDK 1.3 onwards */ 94 private static final Map EMPTY_MAP = new HashMap(); 95 96 /*** the name of the tag to create */ 97 private String name; 98 99 /*** the Java class name to use for the tag */ 100 private String className; 101 102 /*** the ClassLoader used to load beans */ 103 private ClassLoader classLoader; 104 105 /*** the name of the attribute used for the variable name */ 106 private String varAttribute = "var"; 107 108 /*** the attribute definitions for this dynamic tag */ 109 private Map attributes; 110 111 /*** 112 * Adds a new attribute definition to this dynamic tag 113 */ 114 public void addAttribute(Attribute attribute) { 115 if ( attributes == null ) { 116 attributes = new HashMap(); 117 } 118 attributes.put( attribute.getName(), attribute ); 119 } 120 121 // Tag interface 122 //------------------------------------------------------------------------- 123 public void doTag(XMLOutput output) throws Exception { 124 invokeBody(output); 125 126 if (name == null) { 127 throw new MissingAttributeException("name"); 128 } 129 if (className == null) { 130 throw new MissingAttributeException("className"); 131 } 132 133 Class theClass = null; 134 try { 135 ClassLoader classLoader = getClassLoader(); 136 theClass = classLoader.loadClass(className); 137 } 138 catch (ClassNotFoundException e) { 139 try { 140 theClass = getClass().getClassLoader().loadClass(className); 141 } 142 catch (ClassNotFoundException e2) { 143 try { 144 theClass = Class.forName(className); 145 } 146 catch (ClassNotFoundException e3) { 147 log.error( "Could not load class: " + className + " exception: " + e, e ); 148 throw new JellyException( 149 "Could not find class: " 150 + className 151 + " using ClassLoader: " 152 + classLoader); 153 } 154 } 155 } 156 157 final Class beanClass = theClass; 158 final Method invokeMethod = getInvokeMethod( theClass ); 159 final Map beanAttributes = (attributes != null) ? attributes : EMPTY_MAP; 160 161 TagFactory factory = new TagFactory() { 162 public Tag createTag() { 163 return new DynamicBeanTag(beanClass, beanAttributes, varAttribute, invokeMethod); 164 } 165 }; 166 getTagLibrary().registerBeanTag(name, factory); 167 168 // now lets clear the attributes for next invocation and help the GC 169 attributes = null; 170 } 171 172 173 // Properties 174 //------------------------------------------------------------------------- 175 176 /*** 177 * Sets the name of the tag to create 178 */ 179 public void setName(String name) { 180 this.name = name; 181 } 182 183 /*** 184 * Sets the Java class name to use for the tag 185 */ 186 public void setClassName(String className) { 187 this.className = className; 188 } 189 190 /*** 191 * Sets the ClassLoader to use to load the class. 192 * If no value is set then the current threads context class 193 * loader is used. 194 */ 195 public void setClassLoader(ClassLoader classLoader) { 196 this.classLoader = classLoader; 197 } 198 199 /*** 200 * @return the ClassLoader to use to load classes 201 * or will use the thread context loader if none is specified. 202 */ 203 public ClassLoader getClassLoader() { 204 if ( classLoader == null ) { 205 ClassLoader answer = Thread.currentThread().getContextClassLoader(); 206 if ( answer == null ) { 207 answer = getClass().getClassLoader(); 208 } 209 return answer; 210 } 211 return classLoader; 212 } 213 214 /*** 215 * Sets the name of the attribute used to define the bean variable that this dynamic 216 * tag will output its results as. This defaults to 'var' though this property 217 * can be used to change this if it conflicts with a bean property called 'var'. 218 */ 219 public void setVarAttribute(String varAttribute) { 220 this.varAttribute = varAttribute; 221 } 222 223 224 // Implementation methods 225 //------------------------------------------------------------------------- 226 227 /*** 228 * Extracts the invoke method for the class if one is used. 229 */ 230 protected Method getInvokeMethod( Class theClass ) throws Exception { 231 return null; 232 } 233 }

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