Java tutorial
/************************************************************************************** * Copyright (C) 2008 EsperTech, Inc. All rights reserved. * * http://esper.codehaus.org * * http://www.espertech.com * * ---------------------------------------------------------------------------------- * * The software in this package is published under the terms of the GPL license * * a copy of which has been included with this distribution in the license.txt file. * **************************************************************************************/ package com.espertech.esperio.http.config; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.w3c.dom.Document; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import java.io.*; import java.net.URL; import java.util.Map; import java.util.HashMap; import java.util.List; import java.util.ArrayList; public class ConfigurationHTTPAdapter { private static Log log = LogFactory.getLog(ConfigurationHTTPAdapter.class); private Map<String, Service> services; private List<GetHandler> getHandlers; private List<Request> requests; public ConfigurationHTTPAdapter() { services = new HashMap<String, Service>(); getHandlers = new ArrayList<GetHandler>(); requests = new ArrayList<Request>(); } public Map<String, Service> getServices() { return services; } public void setServices(Map<String, Service> services) { this.services = services; } public List<GetHandler> getGetHandlers() { return getHandlers; } public void setGetHandlers(List<GetHandler> getHandlers) { this.getHandlers = getHandlers; } public List<Request> getRequests() { return requests; } public void setRequests(List<Request> requests) { this.requests = requests; } /** * Use the configuration specified in an application * resource named <tt>esper.cfg.xml</tt>. * @return Configuration initialized from the resource * @throws RuntimeException thrown to indicate error reading configuration */ public ConfigurationHTTPAdapter configure() throws RuntimeException { configure('/' + "esperio.http.cfg.xml"); return this; } /** * Use the ConfigurationHTTPAdapter specified in the given application * resource. The format of the resource is defined in * <tt>esper-configuration-2.0.xsd</tt>. * <p/> * The resource is found via <tt>getConfigurationInputStream(resource)</tt>. * That method can be overridden to implement an arbitrary lookup strategy. * <p/> * See <tt>getResourceAsStream</tt> for information on how the resource name is resolved. * @param resource if the file name of the resource * @return ConfigurationHTTPAdapter initialized from the resource * @throws RuntimeException thrown to indicate error reading configuration */ public ConfigurationHTTPAdapter configure(String resource) throws RuntimeException { if (log.isInfoEnabled()) { log.info("Configuring from resource: " + resource); } InputStream stream = getConfigurationInputStream(resource); ConfigurationHTTPAdapterParser.doConfigure(this, stream, resource); return this; } /** * Get the ConfigurationHTTPAdapter file as an <tt>InputStream</tt>. Might be overridden * by subclasses to allow the ConfigurationHTTPAdapter to be located by some arbitrary * mechanism. * <p> * See <tt>getResourceAsStream</tt> for information on how the resource name is resolved. * @param resource is the resource name * @return input stream for resource * @throws RuntimeException thrown to indicate error reading configuration */ protected static InputStream getConfigurationInputStream(String resource) throws RuntimeException { return getResourceAsStream(resource); } /** * Use the ConfigurationHTTPAdapter specified by the given XML String. * The format of the document obtained from the URL is defined in * <tt>esper-configuration-2.0.xsd</tt>. * * @param xml XML string * @return A ConfigurationHTTPAdapter configured via the file * @throws RuntimeException is thrown when the URL could not be access */ public ConfigurationHTTPAdapter configureFromString(String xml) throws RuntimeException { if (log.isInfoEnabled()) { log.info("Configuring from string"); } try { InputSource source = new InputSource(new StringReader(xml)); DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance(); builderFactory.setNamespaceAware(true); Document doc = builderFactory.newDocumentBuilder().parse(source); ConfigurationHTTPAdapterParser.doConfigure(this, doc); return this; } catch (IOException ioe) { throw new RuntimeException("could not configure from String: " + ioe.getMessage(), ioe); } catch (SAXException e) { throw new RuntimeException("could not configure from String: " + e.getMessage(), e); } catch (ParserConfigurationException e) { throw new RuntimeException("could not configure from String: " + e.getMessage(), e); } } /** * Use the ConfigurationHTTPAdapter specified by the given URL. * The format of the document obtained from the URL is defined in * <tt>esper-configuration-2.0.xsd</tt>. * * @param url URL from which you wish to load the configuration * @return A ConfigurationHTTPAdapter configured via the file * @throws RuntimeException is thrown when the URL could not be access */ public ConfigurationHTTPAdapter configure(URL url) throws RuntimeException { if (log.isInfoEnabled()) { log.info("Configuring from url: " + url.toString()); } try { ConfigurationHTTPAdapterParser.doConfigure(this, url.openStream(), url.toString()); return this; } catch (IOException ioe) { throw new RuntimeException("could not configure from URL: " + url, ioe); } } /** * Returns an input stream from an application resource in the classpath. * <p> * The method first removes the '/' character from the resource name if * the first character is '/'. * <p> * The lookup order is as follows: * <p> * If a thread context class loader exists, use <tt>Thread.currentThread().getResourceAsStream</tt> * to obtain an InputStream. * <p> * If no input stream was returned, use the <tt>Configuration.class.getResourceAsStream</tt>. * to obtain an InputStream. * <p> * If no input stream was returned, use the <tt>Configuration.class.getClassLoader().getResourceAsStream</tt>. * to obtain an InputStream. * <p> * If no input stream was returned, throw an Exception. * * @param resource to get input stream for * @return input stream for resource */ protected static InputStream getResourceAsStream(String resource) { String stripped = resource.startsWith("/") ? resource.substring(1) : resource; InputStream stream = null; ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); if (classLoader != null) { stream = classLoader.getResourceAsStream(stripped); } if (stream == null) { stream = ConfigurationHTTPAdapter.class.getResourceAsStream(resource); } if (stream == null) { stream = ConfigurationHTTPAdapter.class.getClassLoader().getResourceAsStream(stripped); } if (stream == null) { throw new RuntimeException(resource + " not found"); } return stream; } /** * Use the ConfigurationHTTPAdapter specified in the given application * file. The format of the file is defined in * <tt>esper-configuration-2.0.xsd</tt>. * * @param configFile <tt>File</tt> from which you wish to load the configuration * @return A ConfigurationHTTPAdapter configured via the file * @throws RuntimeException when the file could not be found */ public ConfigurationHTTPAdapter configure(File configFile) throws RuntimeException { if (log.isDebugEnabled()) { log.debug("configuring from file: " + configFile.getName()); } try { ConfigurationHTTPAdapterParser.doConfigure(this, new FileInputStream(configFile), configFile.toString()); } catch (FileNotFoundException fnfe) { throw new RuntimeException("could not find file: " + configFile, fnfe); } return this; } }