Java tutorial
/******************************************************************************* * Copyright (c)2013 Prometheus Consulting * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. *******************************************************************************/ package nz.co.senanque.madura.configuration; import java.io.FileInputStream; import java.io.InputStream; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.commons.configuration.beanutils.BeanDeclaration; import org.apache.commons.configuration.beanutils.DefaultBeanFactory; import org.apache.commons.configuration.beanutils.XMLBeanDeclaration; import org.apache.commons.configuration.tree.ConfigurationNode; import org.jdom.Attribute; import org.jdom.Document; import org.jdom.Element; import org.jdom.input.SAXBuilder; /** * * This is a factory for apache.commons.config. * You can configure it to return an XML document. It does not cache, but Spring does. * <br/> * <code> * <test1 config-class="org.jdom.Document"<br/> * config-factory="nz.co.senanque.madura.configuration.XMLBeanFactory"><br/> * <A>XYZ</A><br/> * <B>ABC</B><br/> * </test1><br/> * </code> * <br/> * * @author Roger Parkinson * @version $Revision: 1.4 $ */ public class XMLBeanFactory extends DefaultBeanFactory { /** A map for the so far created instances.*/ private Map<String, Object> beans; public XMLBeanFactory() { super(); beans = new HashMap<String, Object>(); } // Creates the bean. Checks if already an instance exists. public synchronized Object createBean(Class beanClass, BeanDeclaration decl, Object param) throws Exception { Map m = decl.getBeanProperties(); XMLBeanDeclaration xmlDecl = (XMLBeanDeclaration) decl; ConfigurationNode n = xmlDecl.getNode(); String nodeName = n.getName(); n = n.getParentNode(); while (n != null) { if (n.getName() != null) nodeName = n.getName() + "/" + nodeName; n = n.getParentNode(); } Object bean = beans.get(nodeName); if (bean != null) { // Yes, there is already an instance return bean; } String fileLocation = (String) m.get("fileLocation"); Document doc = null; SAXBuilder sax = new SAXBuilder(); if (fileLocation == null) { // build the doc from the children ConfigurationNode node = xmlDecl.getNode(); doc = new Document(); doc.addContent(makeElement(node)); } else { InputStream in = new FileInputStream(fileLocation); doc = sax.build(in); } bean = doc; // Store it in map beans.put(nodeName, bean); return bean; } private Element makeElement(ConfigurationNode node) { Element element = new Element(node.getName()); Object value = node.getValue(); if (value != null) element.setText(value.toString()); List<ConfigurationNode> attributes = node.getAttributes(); for (ConfigurationNode attribute : attributes) { element.setAttribute(new Attribute(attribute.getName(), attribute.getValue().toString())); } List<ConfigurationNode> children = node.getChildren(); for (ConfigurationNode child : children) { element.addContent(makeElement(child)); } return element; } }