| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.commons.chain2.web; |
| |
| import java.io.InputStream; |
| import java.net.URL; |
| import java.util.HashSet; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import javax.servlet.ServletContext; |
| import javax.servlet.ServletContextEvent; |
| import javax.servlet.ServletContextListener; |
| |
| import org.apache.commons.chain2.Catalog; |
| import org.apache.commons.chain2.CatalogFactory; |
| import org.apache.commons.chain2.config.xml.XmlConfigParser; |
| import org.apache.commons.chain2.config.xml.XmlConfigParser; |
| import org.apache.commons.chain2.impl.CatalogBase; |
| import org.apache.commons.chain2.web.servlet.ServletWebContext; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * <p><code>ServletContextListener</code> that automatically |
| * scans chain configuration files in the current web application at |
| * startup time, and exposes the result in a {@link Catalog} under a |
| * specified servlet context attribute. The following <em>context</em> init |
| * parameters are utilized:</p> |
| * <ul> |
| * <li><strong>org.apache.commons.chain2.CONFIG_CLASS_RESOURCE</strong> - |
| * comma-delimited list of chain configuration resources to be loaded |
| * via <code>ClassLoader.getResource()</code> calls. If not specified, |
| * no class loader resources will be loaded.</li> |
| * <li><strong>org.apache.commons.chain2.CONFIG_WEB_RESOURCE</strong> - |
| * comma-delimited list of chain configuration webapp resources |
| * to be loaded. If not specified, no web application resources |
| * will be loaded.</li> |
| * <li><strong>org.apache.commons.chain2.CONFIG_ATTR</strong> - |
| * Name of the servlet context attribute under which the |
| * resulting {@link Catalog} will be created or updated. |
| * If not specified, it is expected that parsed resources will |
| * contain <code><catalog></code> elements (which will |
| * cause registration of the created {@link Catalog}s into |
| * the {@link CatalogFactory} for this application, and no |
| * servlet context attribute will be created. |
| * <strong>NOTE</strong> - This parameter is deprecated.</p> |
| * <li><strong>org.apache.commons.chain2.RULE_SET</strong> - |
| * Fully qualified class name of a Digester <code>RuleSet</code> |
| * implementation to use for parsing configuration resources (this |
| * class must have a public zero-args constructor). If not defined, |
| * the standard <code>RuleSet</code> implementation will be used.</li> |
| * </ul> |
| * |
| * <p>When a web application that has configured this listener is |
| * started, it will acquire the {@link Catalog} under the specified servlet |
| * context attribute key, creating a new one if there is none already there. |
| * This {@link Catalog} will then be populated by scanning configuration |
| * resources from the following sources (loaded in this order):</p> |
| * <ul> |
| * <li>Resources loaded from any <code>META-INF/chain-config.xml</code> |
| * resource found in a JAR file in <code>/WEB-INF/lib</code>.</li> |
| * <li>Resources loaded from specified resource paths from the |
| * webapp's class loader (via <code>ClassLoader.getResource()</code>).</li> |
| * <li>Resources loaded from specified resource paths in the web application |
| * archive (via <code>ServletContext.getResource()</code>).</li> |
| * </ul> |
| * |
| * <p>If no attribute key is specified, on the other hand, parsed configuration |
| * resources are expected to contain <code><catalog></code> elements, |
| * and the catalogs will be registered with the {@link CatalogFactory} |
| * for this web application.</p> |
| * |
| * <p>This class requires Servlet 2.3 or later. If you are running on |
| * Servlet 2.2 system, consider using {@link ChainServlet} instead. |
| * Note that {@link ChainServlet} uses parameters of the |
| * same names, but they are <em>servlet</em> init parameters instead |
| * of <em>context</em> init parameters. Because of this, you can use |
| * both facilities in the same application, if desired.</p> |
| * |
| * @version $Id$ |
| */ |
| public class ChainListener implements ServletContextListener { |
| { |
| CatalogFactory.checkForValidConfigurationModule(); |
| } |
| |
| // ------------------------------------------------------ Manifest Constants |
| |
| /** |
| * <p>The name of the context init parameter containing the name of the |
| * servlet context attribute under which our resulting {@link Catalog} |
| * will be stored.</p> |
| */ |
| public static final String CONFIG_ATTR = |
| "org.apache.commons.chain2.CONFIG_ATTR"; |
| |
| /** |
| * <p>The name of the context init parameter containing a comma-delimited |
| * list of class loader resources to be scanned.</p> |
| */ |
| public static final String CONFIG_CLASS_RESOURCE = |
| "org.apache.commons.chain2.CONFIG_CLASS_RESOURCE"; |
| |
| /** |
| * <p>The name of the context init parameter containing a comma-delimited |
| * list of web applicaton resources to be scanned.</p> |
| */ |
| public static final String CONFIG_WEB_RESOURCE = |
| "org.apache.commons.chain2.CONFIG_WEB_RESOURCE"; |
| |
| /** |
| * <p>The name of the context init parameter containing the fully |
| * qualified class name of the <code>RuleSet</code> implementation |
| * for configuring our {@link XmlConfigParser}.</p> |
| */ |
| public static final String RULE_SET = |
| "org.apache.commons.chain2.RULE_SET"; |
| |
| // ------------------------------------------ ServletContextListener Methods |
| |
| /** |
| * <p>Remove the configured {@link Catalog} from the servlet context |
| * attributes for this web application.</p> |
| * |
| * @param event <code>ServletContextEvent</code> to be processed |
| */ |
| public void contextDestroyed(ServletContextEvent event) { |
| ServletContext context = event.getServletContext(); |
| String attr = context.getInitParameter(CONFIG_ATTR); |
| if (attr != null) { |
| context.removeAttribute(attr); |
| } |
| CatalogFactory.clear(); |
| } |
| |
| /** |
| * <p>Scan the required chain configuration resources, assemble the |
| * configured chains into a {@link Catalog}, and expose it as a |
| * servlet context attribute under the specified key.</p> |
| * |
| * @param event <code>ServletContextEvent</code> to be processed |
| */ |
| public void contextInitialized(ServletContextEvent event) { |
| Log log = LogFactory.getLog(ChainListener.class); |
| if (log.isInfoEnabled()) { |
| log.info("Initializing chain listener"); |
| } |
| ServletContext context = event.getServletContext(); |
| |
| // Retrieve context init parameters that we need |
| String attr = context.getInitParameter(CONFIG_ATTR); |
| String classResources = |
| context.getInitParameter(CONFIG_CLASS_RESOURCE); |
| String ruleSet = context.getInitParameter(RULE_SET); |
| String webResources = context.getInitParameter(CONFIG_WEB_RESOURCE); |
| |
| // Retrieve or create the Catalog instance we may be updating |
| Catalog<String, Object, ServletWebContext<String, Object>> catalog = null; |
| if (attr != null) { |
| Object catalogRef = context.getAttribute(attr); |
| |
| if (catalogRef == null || !(catalogRef instanceof Catalog) ) { |
| catalog = new CatalogBase<String, Object, ServletWebContext<String, Object>>(); |
| } else { |
| /* Assume that we are getting an object of the type Catalog from the context's |
| * attribute because that is the historical contract. */ |
| catalog = (Catalog<String, Object, ServletWebContext<String, Object>>)catalogRef; |
| } |
| } |
| |
| // Construct the configuration resource parser we will use |
| ClassLoader cl = Thread.currentThread().getContextClassLoader() == null ? |
| this.getClass().getClassLoader() : |
| Thread.currentThread().getContextClassLoader(); |
| |
| XmlConfigParser parser = ruleSet == null ? |
| new XmlConfigParser() : new XmlConfigParser(ruleSet, cl); |
| |
| // Parse the resources specified in our init parameters (if any) |
| if (attr == null) { |
| parseJarResources(context, parser, log); |
| ChainResources.parseClassResources |
| (classResources, parser); |
| ChainResources.parseWebResources |
| (context, webResources, parser); |
| } else { |
| parseJarResources(context, parser, log); |
| ChainResources.parseClassResources |
| (classResources, parser); |
| ChainResources.parseWebResources |
| (context, webResources, parser); |
| } |
| |
| // Expose the completed catalog (if requested) |
| if (attr != null) { |
| context.setAttribute(attr, catalog); |
| } |
| } |
| |
| // --------------------------------------------------------- Private Methods |
| |
| /** |
| * <p>Parse resources found in JAR files in the <code>/WEB-INF/lib</code> |
| * subdirectory (if any).</p> |
| * |
| * @param context <code>ServletContext</code> for this web application |
| * @param parser {@link XmlConfigParser} to use for parsing |
| */ |
| private void parseJarResources(ServletContext context, |
| XmlConfigParser parser, Log log) { |
| @SuppressWarnings( "unchecked" ) // it is known that always returns String inside |
| Set<String> jars = context.getResourcePaths("/WEB-INF/lib"); |
| if (jars == null) { |
| jars = new HashSet<String>(); |
| } |
| String path; |
| |
| for (String jar : jars) { |
| |
| path = jar; |
| if (!path.endsWith(".jar")) { |
| continue; |
| } |
| URL resourceURL = null; |
| try { |
| URL jarURL = context.getResource(path); |
| resourceURL = new URL("jar:" |
| + translate(jarURL.toExternalForm()) |
| + "!/META-INF/chain-config.xml"); |
| InputStream is = null; |
| try { |
| is = resourceURL.openStream(); |
| } catch (Exception e) { |
| // means there is no such resource |
| } |
| if (is == null) { |
| if (log.isDebugEnabled()) { |
| log.debug("Not Found: " + resourceURL); |
| } |
| continue; |
| } else { |
| is.close(); |
| } |
| if (log.isDebugEnabled()) { |
| log.debug("Parsing: " + resourceURL); |
| } |
| @SuppressWarnings("unused") // FIXME we have to assign the factory here to help the compiler with the type arguments |
| CatalogFactory<Object, Object,Map<Object,Object>> factory = parser.parse(resourceURL); |
| } catch (Exception e) { |
| String externalURL = "null"; |
| if (resourceURL != null) { |
| externalURL = resourceURL.toExternalForm(); |
| } |
| throw new RuntimeException |
| ("Exception parsing chain config resource '" |
| + externalURL + "': " |
| + e.getMessage()); |
| } |
| } |
| } |
| |
| /** |
| * <p>Translate space character into <code>&pct;20</code> to avoid problems |
| * with paths that contain spaces on some JVMs.</p> |
| * |
| * @param value Value to translate |
| */ |
| private String translate(String value) { |
| while (true) { |
| int index = value.indexOf(' '); |
| if (index < 0) { |
| break; |
| } |
| value = value.substring(0, index) + "%20" + value.substring(index + 1); |
| } |
| return (value); |
| } |
| |
| } |
