Java tutorial
/******************************************************************************* * This file is part of OpenNMS(R). * * Copyright (C) 2012 The OpenNMS Group, Inc. * OpenNMS(R) is Copyright (C) 1999-2012 The OpenNMS Group, Inc. * * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc. * * OpenNMS(R) is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published * by the Free Software Foundation, either version 3 of the License, * or (at your option) any later version. * * OpenNMS(R) is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with OpenNMS(R). If not, see: * http://www.gnu.org/licenses/ * * For more information contact: * OpenNMS(R) Licensing <license@opennms.org> * http://www.opennms.org/ * http://www.opennms.com/ *******************************************************************************/ package com.netxforge.oss2.config; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStreamWriter; import java.io.Writer; import org.apache.commons.io.IOUtils; import org.exolab.castor.xml.MarshalException; import org.exolab.castor.xml.ValidationException; import org.opennms.core.utils.ConfigFileConstants; import org.opennms.core.utils.ThreadCategory; /** * This is the singleton class used to load the configuration for the OpenNMS * Thresholding Daemon from the threshd-configuration xml file. * * A mapping of the configured URLs to the iplist they contain is built at * init() time so as to avoid numerous file reads. * * <strong>Note: </strong>Users of this class should make sure the * <em>init()</em> is called before calling any other method to ensure the * config is loaded before accessing other convenience methods. * * @author <a href="mailto:jamesz@opennms.com>James Zuo </a> * @author <a href="mailto:mike@opennms.org">Mike Davidson </a> * @author <a href="mailto:sowmya@opennms.org">Sowmya Nataraj </a> * @author <a href="http://www.opennms.org/">OpenNMS </a> */ public final class ThreshdConfigFactory extends ThreshdConfigManager { /** * The singleton instance of this factory */ private static ThreshdConfigFactory m_singleton = null; /** * This member is set to true if the configuration file has been loaded. */ private static boolean m_loaded = false; /** * <p>Constructor for ThreshdConfigFactory.</p> * * @param stream a {@link java.io.InputStream} object. * @param localServer a {@link java.lang.String} object. * @param verifyServer a boolean. * @throws java.io.IOException if any. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ public ThreshdConfigFactory(InputStream stream, String localServer, boolean verifyServer) throws IOException, MarshalException, ValidationException { super(stream, localServer, verifyServer); } /** * Load the config from the default config file and create the singleton * instance of this factory. * * @exception java.io.IOException * Thrown if the specified config file cannot be read * @exception org.exolab.castor.xml.MarshalException * Thrown if the file does not conform to the schema. * @exception org.exolab.castor.xml.ValidationException * Thrown if the contents do not match the required schema. * @throws java.io.IOException if any. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ public static synchronized void init() throws IOException, MarshalException, ValidationException { if (m_loaded) { // init already called - return // to reload, reload() will need to be called return; } OpennmsServerConfigFactory.init(); boolean verifyServer = OpennmsServerConfigFactory.getInstance().verifyServer(); String localServer = OpennmsServerConfigFactory.getInstance().getServerName(); File cfgFile = ConfigFileConstants.getFile(ConfigFileConstants.THRESHD_CONFIG_FILE_NAME); ThreadCategory.getInstance(ThreshdConfigFactory.class) .debug("init: config file path: " + cfgFile.getPath()); InputStream stream = null; try { stream = new FileInputStream(cfgFile); m_singleton = new ThreshdConfigFactory(stream, localServer, verifyServer); m_loaded = true; } finally { if (stream != null) { IOUtils.closeQuietly(stream); } } } /** * Reload the config from the default config file * * @exception java.io.IOException * Thrown if the specified config file cannot be read/loaded * @exception org.exolab.castor.xml.MarshalException * Thrown if the file does not conform to the schema. * @exception org.exolab.castor.xml.ValidationException * Thrown if the contents do not match the required schema. * @throws java.io.IOException if any. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ public static synchronized void reload() throws IOException, MarshalException, ValidationException { m_singleton = null; m_loaded = false; init(); } /** * <p>reloadXML</p> * * @throws java.io.IOException if any. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ public void reloadXML() throws IOException, MarshalException, ValidationException { /* FIXME: THIS IS WAY WRONG! Should only reload the xml not recreate the instance otherwise references to the old instance will still linger */ reload(); } /** {@inheritDoc} */ protected void saveXML(String xmlString) throws IOException { File cfgFile = ConfigFileConstants.getFile(ConfigFileConstants.THRESHD_CONFIG_FILE_NAME); Writer fileWriter = new OutputStreamWriter(new FileOutputStream(cfgFile), "UTF-8"); fileWriter.write(xmlString); fileWriter.flush(); fileWriter.close(); } /** * Return the singleton instance of this factory. * * @return The current factory instance. * @throws java.lang.IllegalStateException * Thrown if the factory has not yet been initialized. */ public static synchronized ThreshdConfigFactory getInstance() { if (!m_loaded) throw new IllegalStateException("The factory has not been initialized"); return m_singleton; } /** * <p>setInstance</p> * * @param configFactory a {@link org.opennms.netmgt.config.ThreshdConfigFactory} object. */ public static void setInstance(ThreshdConfigFactory configFactory) { m_loaded = true; m_singleton = configFactory; } }