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.socket.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.HashMap; import java.util.Map; public class ConfigurationSocketAdapter { private static Log log = LogFactory.getLog(ConfigurationSocketAdapter.class); private Map<String, SocketConfig> sockets; public ConfigurationSocketAdapter() { sockets = new HashMap<String, SocketConfig>(); } public Map<String, SocketConfig> getSockets() { return sockets; } public void setSockets(Map<String, SocketConfig> sockets) { this.sockets = sockets; } /** * 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 ConfigurationSocketAdapter configure() throws RuntimeException { configure('/' + "esperio.socket.cfg.xml"); return this; } /** * Use the ConfigurationSocketAdapter 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 ConfigurationSocketAdapter initialized from the resource * @throws RuntimeException thrown to indicate error reading configuration */ public ConfigurationSocketAdapter configure(String resource) throws RuntimeException { if (log.isInfoEnabled()) { log.info("Configuring from resource: " + resource); } InputStream stream = getConfigurationInputStream(resource); ConfigurationSocketAdapterParser.doConfigure(this, stream, resource); return this; } /** * Get the ConfigurationSocketAdapter file as an <tt>InputStream</tt>. Might be overridden * by subclasses to allow the ConfigurationSocketAdapter 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 ConfigurationSocketAdapter 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 ConfigurationSocketAdapter configured via the file * @throws RuntimeException is thrown when the URL could not be access */ public ConfigurationSocketAdapter 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); ConfigurationSocketAdapterParser.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 ConfigurationSocketAdapter 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 ConfigurationSocketAdapter configured via the file * @throws RuntimeException is thrown when the URL could not be access */ public ConfigurationSocketAdapter configure(URL url) throws RuntimeException { if (log.isInfoEnabled()) { log.info("Configuring from url: " + url.toString()); } try { ConfigurationSocketAdapterParser.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 = ConfigurationSocketAdapter.class.getResourceAsStream(resource); } if (stream == null) { stream = ConfigurationSocketAdapter.class.getClassLoader().getResourceAsStream(stripped); } if (stream == null) { throw new RuntimeException(resource + " not found"); } return stream; } /** * Use the ConfigurationSocketAdapter 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 ConfigurationSocketAdapter configured via the file * @throws RuntimeException when the file could not be found */ public ConfigurationSocketAdapter configure(File configFile) throws RuntimeException { if (log.isDebugEnabled()) { log.debug("configuring from file: " + configFile.getName()); } FileInputStream inputStream = null; try { inputStream = new FileInputStream(configFile); ConfigurationSocketAdapterParser.doConfigure(this, inputStream, configFile.toString()); } catch (FileNotFoundException fnfe) { throw new RuntimeException("could not find file: " + configFile, fnfe); } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { log.debug("Error closing input stream", e); } } } return this; } }