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1 /* 2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/tags/define/DynamicTag.java,v 1.7 2002/05/17 15:18:12 jstrachan Exp $ 3 * $Revision: 1.7 $ 4 * $Date: 2002/05/17 15:18:12 $ 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: DynamicTag.java,v 1.7 2002/05/17 15:18:12 jstrachan Exp $ 61 */ 62 package org.apache.commons.jelly.impl; 63 64 import java.util.HashSet; 65 import java.util.Iterator; 66 import java.util.Map; 67 import java.util.Set; 68 69 import org.apache.commons.beanutils.DynaBean; 70 import org.apache.commons.beanutils.DynaClass; 71 72 import org.apache.commons.jelly.DynaBeanTagSupport; 73 import org.apache.commons.jelly.JellyException; 74 import org.apache.commons.jelly.MissingAttributeException; 75 import org.apache.commons.jelly.Tag; 76 import org.apache.commons.jelly.XMLOutput; 77 import org.apache.commons.jelly.expression.Expression; 78 import org.apache.commons.jelly.impl.BeanSource; 79 80 import org.apache.commons.logging.Log; 81 import org.apache.commons.logging.LogFactory; 82 83 /*** 84 * This tag is bound onto a {@link DynaClass} instance. 85 * When the tag is invoked a {@link DynaBean will be created using the tags attributes. 86 * So this class is like a {@link DynaBean} implemenation of {@link DynamicBeanTag} 87 * 88 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> 89 * @version $Revision: 1.7 $ 90 */ 91 public class DynamicDynaBeanTag extends DynaBeanTagSupport implements BeanSource { 92 93 /*** The Log to which logging calls will be made. */ 94 private static final Log log = LogFactory.getLog(DynamicDynaBeanTag.class); 95 96 /*** the bean class */ 97 private DynaClass beanClass; 98 99 /*** 100 * the tag attribute name that is used to declare the name 101 * of the variable to export after running this tag 102 */ 103 private String variableNameAttribute; 104 105 /*** the current variable name that the bean should be exported as */ 106 private String var; 107 108 /*** the set of attribute names we've already set */ 109 private Set setAttributesSet = new HashSet(); 110 111 /*** the attribute definitions */ 112 private Map attributes; 113 114 public DynamicDynaBeanTag(DynaClass beanClass, Map attributes, String variableNameAttribute) { 115 this.beanClass = beanClass; 116 this.attributes = attributes; 117 this.variableNameAttribute = variableNameAttribute; 118 } 119 120 public void beforeSetAttributes() throws Exception { 121 // create a new dynabean before the attributes are set 122 setDynaBean( beanClass.newInstance() ); 123 124 setAttributesSet.clear(); 125 } 126 127 public void setAttribute(String name, Object value) throws Exception { 128 boolean isVariableName = false; 129 if (variableNameAttribute != null ) { 130 if ( variableNameAttribute.equals( name ) ) { 131 if (value == null) { 132 var = null; 133 } 134 else { 135 var = value.toString(); 136 } 137 isVariableName = true; 138 } 139 } 140 if (! isVariableName) { 141 142 // #### strictly speaking we could 143 // know what attributes are specified at compile time 144 // so this dynamic set is unnecessary 145 setAttributesSet.add(name); 146 147 // we could maybe implement attribute specific validation here 148 149 super.setAttribute(name, value); 150 } 151 } 152 153 // Tag interface 154 //------------------------------------------------------------------------- 155 public void doTag(XMLOutput output) throws Exception { 156 157 // lets find any attributes that are not set and 158 for ( Iterator iter = attributes.values().iterator(); iter.hasNext(); ) { 159 Attribute attribute = (Attribute) iter.next(); 160 String name = attribute.getName(); 161 if ( ! setAttributesSet.contains( name ) ) { 162 if ( attribute.isRequired() ) { 163 throw new MissingAttributeException(name); 164 } 165 // lets get the default value 166 Object value = null; 167 Expression expression = attribute.getDefaultValue(); 168 if ( expression != null ) { 169 value = expression.evaluate(context); 170 } 171 172 // only set non-null values? 173 if ( value != null ) { 174 super.setAttribute(name, value); 175 } 176 } 177 } 178 179 invokeBody(output); 180 181 // export the bean if required 182 if ( var != null ) { 183 context.setVariable(var, getDynaBean()); 184 } 185 } 186 187 // Properties 188 //------------------------------------------------------------------------- 189 /*** 190 * @return the bean that has just been created 191 */ 192 public Object getBean() { 193 return getDynaBean(); 194 } 195 }

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