Java tutorial
/** * $RCSfile$ * $Revision: 11388 $ * $Date: 2009-11-08 19:26:55 -0500 (Sun, 08 Nov 2009) $ * * Copyright (C) 2004-2008 B5Chat Community. All rights reserved. * * 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 org.b5chat.crossfire.plugin.admin; import java.io.InputStream; import java.net.URL; import java.util.Enumeration; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; import org.b5chat.crossfire.core.util.ClassUtils; import org.b5chat.crossfire.core.util.LocaleUtils; import org.b5chat.crossfire.xmpp.server.XmppServer; import org.dom4j.Document; import org.dom4j.DocumentFactory; import org.dom4j.Element; import org.dom4j.io.SAXReader; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * A model for admin tab and sidebar info. This class loads in XML definitions of the * data and produces an in-memory model.<p> * * This class loads its data from the <tt>admin-sidebar.xml</tt> file which is assumed * to be in the main application jar file. In addition, it will load files from * <tt>META-INF/admin-sidebar.xml</tt> if they're found. This allows developers to * extend the functionality of the admin console to provide more options. See the main * <tt>admin-sidebar.xml</tt> file for documentation of its format. */ public class AdminConsole { private static final Logger Log = LoggerFactory.getLogger(AdminConsole.class); private static Element coreModel; private static Map<String, Element> overrideModels; private static Element generatedModel; static { overrideModels = new LinkedHashMap<String, Element>(); load(); } /** Not instantiatable */ private AdminConsole() { } /** * Adds XML stream to the tabs/sidebar model. * * @param name the name. * @param in the XML input stream. * @throws Exception if an error occurs when parsing the XML or adding it to the model. */ public static void addModel(String name, InputStream in) throws Exception { SAXReader saxReader = new SAXReader(); Document doc = saxReader.read(in); addModel(name, (Element) doc.selectSingleNode("/adminconsole")); } /** * Adds an <adminconsole> Element to the tabs/sidebar model. * * @param name the name. * @param element the Element * @throws Exception if an error occurs. */ public static void addModel(String name, Element element) throws Exception { overrideModels.put(name, element); rebuildModel(); } /** * Removes an <adminconsole> Element from the tabs/sidebar model. * * @param name the name. */ public static void removeModel(String name) { overrideModels.remove(name); rebuildModel(); } /** * Returns the name of the application. * * @return the name of the application. */ public static synchronized String getAppName() { Element appName = (Element) generatedModel.selectSingleNode("//adminconsole/global/appname"); if (appName != null) { String pluginName = appName.attributeValue("plugin"); return getAdminText(appName.getText(), pluginName); } else { return null; } } /** * Returns the URL of the main logo image for the admin console. * * @return the logo image. */ public static synchronized String getLogoImage() { Element globalLogoImage = (Element) generatedModel.selectSingleNode("//adminconsole/global/logo-image"); if (globalLogoImage != null) { String pluginName = globalLogoImage.attributeValue("plugin"); return getAdminText(globalLogoImage.getText(), pluginName); } else { return null; } } /** * Returns the URL of the login image for the admin console. * * @return the login image. */ public static synchronized String getLoginLogoImage() { Element globalLoginLogoImage = (Element) generatedModel .selectSingleNode("//adminconsole/global/login-image"); if (globalLoginLogoImage != null) { String pluginName = globalLoginLogoImage.attributeValue("plugin"); return getAdminText(globalLoginLogoImage.getText(), pluginName); } else { return null; } } /** * Returns the version string displayed in the admin console. * * @return the version string. */ public static synchronized String getVersionString() { Element globalVersion = (Element) generatedModel.selectSingleNode("//adminconsole/global/version"); if (globalVersion != null) { String pluginName = globalVersion.attributeValue("plugin"); return getAdminText(globalVersion.getText(), pluginName); } else { // Default to the crossfire version if none has been provided via XML. XmppServer xmppServer = XmppServer.getInstance(); return xmppServer.getServerInfo().getVersion().getVersionString(); } } /** * Returns the model. The model should be considered read-only. * * @return the model. */ public static synchronized Element getModel() { return generatedModel; } /** * Convenience method to select an element from the model by its ID. If an * element with a matching ID is not found, <tt>null</tt> will be returned. * * @param id the ID. * @return the element. */ public static synchronized Element getElemnetByID(String id) { return (Element) generatedModel.selectSingleNode("//*[@id='" + id + "']"); } /** * Returns a text element for the admin console, applying the appropriate locale. * Internationalization logic will only be applied if the String is specially encoded * in the format "${key.name}". If it is, the String is pulled from the resource bundle. * If the pluginName is not <tt>null</tt>, the plugin's resource bundle will be used * to look up the key. * * @param string the String. * @param pluginName the name of the plugin that the i18n String can be found in, * or <tt>null</tt> if the standard crossfire resource bundle should be used. * @return the string, or if the string is encoded as an i18n key, the value from * the appropriate resource bundle. */ public static String getAdminText(String string, String pluginName) { if (string == null) { return null; } // Look for the key symbol: if (string.indexOf("${") == 0 && string.indexOf("}") == string.length() - 1) { return LocaleUtils.getLocalizedString(string.substring(2, string.length() - 1), pluginName); } return string; } private static void load() { // Load the core model as the admin-sidebar.xml file from the classpath. InputStream in = ClassUtils.getResourceAsStream("/admin-sidebar.xml"); if (in == null) { Log.error("Failed to load admin-sidebar.xml file from crossfire classes - admin " + "console will not work correctly."); return; } try { SAXReader saxReader = new SAXReader(); Document doc = saxReader.read(in); coreModel = (Element) doc.selectSingleNode("/adminconsole"); } catch (Exception e) { Log.error("Failure when parsing main admin-sidebar.xml file", e); } try { in.close(); } catch (Exception ignored) { // Ignore. } // Load other admin-sidebar.xml files from the classpath ClassLoader[] classLoaders = getClassLoaders(); for (ClassLoader classLoader : classLoaders) { URL url = null; try { if (classLoader != null) { Enumeration<URL> e = classLoader.getResources("/META-INF/admin-sidebar.xml"); while (e.hasMoreElements()) { url = e.nextElement(); try { in = url.openStream(); addModel("admin", in); } finally { try { if (in != null) { in.close(); } } catch (Exception ignored) { // Ignore. } } } } } catch (Exception e) { String msg = "Failed to load admin-sidebar.xml"; if (url != null) { msg += " from resource: " + url.toString(); } Log.warn(msg, e); } } rebuildModel(); } /** * Rebuilds the generated model. */ private static synchronized void rebuildModel() { Document doc = DocumentFactory.getInstance().createDocument(); generatedModel = coreModel.createCopy(); doc.add(generatedModel); // Add in all overrides. for (Element element : overrideModels.values()) { // See if global settings are overriden. Element appName = (Element) element.selectSingleNode("//adminconsole/global/appname"); if (appName != null) { Element existingAppName = (Element) generatedModel .selectSingleNode("//adminconsole/global/appname"); existingAppName.setText(appName.getText()); if (appName.attributeValue("plugin") != null) { existingAppName.addAttribute("plugin", appName.attributeValue("plugin")); } } Element appLogoImage = (Element) element.selectSingleNode("//adminconsole/global/logo-image"); if (appLogoImage != null) { Element existingLogoImage = (Element) generatedModel .selectSingleNode("//adminconsole/global/logo-image"); existingLogoImage.setText(appLogoImage.getText()); if (appLogoImage.attributeValue("plugin") != null) { existingLogoImage.addAttribute("plugin", appLogoImage.attributeValue("plugin")); } } Element appLoginImage = (Element) element.selectSingleNode("//adminconsole/global/login-image"); if (appLoginImage != null) { Element existingLoginImage = (Element) generatedModel .selectSingleNode("//adminconsole/global/login-image"); existingLoginImage.setText(appLoginImage.getText()); if (appLoginImage.attributeValue("plugin") != null) { existingLoginImage.addAttribute("plugin", appLoginImage.attributeValue("plugin")); } } Element appVersion = (Element) element.selectSingleNode("//adminconsole/global/version"); if (appVersion != null) { Element existingVersion = (Element) generatedModel .selectSingleNode("//adminconsole/global/version"); if (existingVersion != null) { existingVersion.setText(appVersion.getText()); if (appVersion.attributeValue("plugin") != null) { existingVersion.addAttribute("plugin", appVersion.attributeValue("plugin")); } } else { ((Element) generatedModel.selectSingleNode("//adminconsole/global")) .add(appVersion.createCopy()); } } // Tabs for (Object o : element.selectNodes("//tab")) { Element tab = (Element) o; String id = tab.attributeValue("id"); Element existingTab = getElemnetByID(id); // Simple case, there is no existing tab with the same id. if (existingTab == null) { // Make sure that the URL on the tab is set. If not, default to the // url of the first item. if (tab.attributeValue("url") == null) { Element firstItem = (Element) tab.selectSingleNode("//item[@url]"); if (firstItem != null) { tab.addAttribute("url", firstItem.attributeValue("url")); } } generatedModel.add(tab.createCopy()); } // More complex case -- a tab with the same id already exists. // In this case, we have to overrite only the difference between // the two elements. else { overrideTab(existingTab, tab); } } } } private static void overrideTab(Element tab, Element overrideTab) { // Override name, url, description. if (overrideTab.attributeValue("name") != null) { tab.addAttribute("name", overrideTab.attributeValue("name")); } if (overrideTab.attributeValue("url") != null) { tab.addAttribute("url", overrideTab.attributeValue("url")); } if (overrideTab.attributeValue("description") != null) { tab.addAttribute("description", overrideTab.attributeValue("description")); } if (overrideTab.attributeValue("plugin") != null) { tab.addAttribute("plugin", overrideTab.attributeValue("plugin")); } // Override sidebar items. for (@SuppressWarnings("unchecked") Iterator<Element> i = overrideTab.elementIterator(); i.hasNext();) { Element sidebar = (Element) i.next(); String id = sidebar.attributeValue("id"); Element existingSidebar = getElemnetByID(id); // Simple case, there is no existing sidebar with the same id. if (existingSidebar == null) { tab.add(sidebar.createCopy()); } // More complex case -- a sidebar with the same id already exists. // In this case, we have to overrite only the difference between // the two elements. else { overrideSidebar(existingSidebar, sidebar); } } } private static void overrideSidebar(Element sidebar, Element overrideSidebar) { // Override name. if (overrideSidebar.attributeValue("name") != null) { sidebar.addAttribute("name", overrideSidebar.attributeValue("name")); } if (overrideSidebar.attributeValue("plugin") != null) { sidebar.addAttribute("plugin", overrideSidebar.attributeValue("plugin")); } // Override entries. for (@SuppressWarnings("unchecked") Iterator<Element> i = overrideSidebar.elementIterator(); i.hasNext();) { Element entry = (Element) i.next(); String id = entry.attributeValue("id"); Element existingEntry = getElemnetByID(id); // Simple case, there is no existing sidebar with the same id. if (existingEntry == null) { sidebar.add(entry.createCopy()); } // More complex case -- an entry with the same id already exists. // In this case, we have to overrite only the difference between // the two elements. else { overrideEntry(existingEntry, entry); } } } private static void overrideEntry(Element entry, Element overrideEntry) { // Override name. if (overrideEntry.attributeValue("name") != null) { entry.addAttribute("name", overrideEntry.attributeValue("name")); } if (overrideEntry.attributeValue("url") != null) { entry.addAttribute("url", overrideEntry.attributeValue("url")); } if (overrideEntry.attributeValue("description") != null) { entry.addAttribute("description", overrideEntry.attributeValue("description")); } if (overrideEntry.attributeValue("plugin") != null) { entry.addAttribute("plugin", overrideEntry.attributeValue("plugin")); } // Override any sidebars contained in the entry. for (@SuppressWarnings("unchecked") Iterator<Element> i = overrideEntry.elementIterator(); i.hasNext();) { Element sidebar = (Element) i.next(); String id = sidebar.attributeValue("id"); Element existingSidebar = getElemnetByID(id); // Simple case, there is no existing sidebar with the same id. if (existingSidebar == null) { entry.add(sidebar.createCopy()); } // More complex case -- a sidebar with the same id already exists. // In this case, we have to overrite only the difference between // the two elements. else { overrideSidebar(existingSidebar, sidebar); } } } /** * Returns an array of class loaders to load resources from. * * @return an array of class loaders to load resources from. */ private static ClassLoader[] getClassLoaders() { ClassLoader[] classLoaders = new ClassLoader[3]; classLoaders[0] = AdminConsole.class.getClass().getClassLoader(); classLoaders[1] = Thread.currentThread().getContextClassLoader(); classLoaders[2] = ClassLoader.getSystemClassLoader(); return classLoaders; } }