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.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.util.List; 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; import org.opennms.core.xml.CastorUtils; import org.opennms.netmgt.config.httpdatacollection.HttpCollection; import org.opennms.netmgt.config.httpdatacollection.HttpDatacollectionConfig; import org.opennms.netmgt.model.RrdRepository; /** * <p>HttpCollectionConfigFactory class.</p> * * @author <a href="mailto:david@opennms.org">David Hustace</a> * @version $Id: $ */ public class HttpCollectionConfigFactory { /** The singleton instance. */ private static HttpCollectionConfigFactory m_instance; private static boolean m_loadedFromFile = false; /** Boolean indicating if the init() method has been called. */ protected boolean initialized = false; /** Timestamp of the http collection config, used to know when to reload from disk. */ protected static long m_lastModified; private static HttpDatacollectionConfig m_config; /** * <p>Constructor for HttpCollectionConfigFactory.</p> * * @param configFile a {@link java.lang.String} object. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. * @throws java.io.IOException if any. */ public HttpCollectionConfigFactory(String configFile) throws MarshalException, ValidationException, IOException { InputStream is = null; try { is = new FileInputStream(configFile); initialize(is); } finally { if (is != null) { IOUtils.closeQuietly(is); } } } /** * <p>Constructor for HttpCollectionConfigFactory.</p> * * @param stream a {@link java.io.InputStream} object. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ public HttpCollectionConfigFactory(InputStream stream) throws MarshalException, ValidationException { initialize(stream); } private void initialize(InputStream stream) throws MarshalException, ValidationException { log().debug("initialize: initializing http collection config factory."); m_config = CastorUtils.unmarshal(HttpDatacollectionConfig.class, stream); } /** * Be sure to call this method before calling getInstance(). * * @throws java.io.IOException if any. * @throws java.io.FileNotFoundException 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, FileNotFoundException, MarshalException, ValidationException { if (m_instance == null) { File cfgFile = ConfigFileConstants.getFile(ConfigFileConstants.HTTP_COLLECTION_CONFIG_FILE_NAME); m_instance = new HttpCollectionConfigFactory(cfgFile.getPath()); m_lastModified = cfgFile.lastModified(); m_loadedFromFile = true; } } /** * Singleton static call to get the only instance that should exist * * @return the single factory instance * @throws java.lang.IllegalStateException * if init has not been called */ public static synchronized HttpCollectionConfigFactory getInstance() { if (m_instance == null) { throw new IllegalStateException( "You must call HttpCollectionConfigFactory.init() before calling getInstance()."); } return m_instance; } /** * <p>setInstance</p> * * @param instance a {@link org.opennms.netmgt.config.HttpCollectionConfigFactory} object. */ public static synchronized void setInstance(HttpCollectionConfigFactory instance) { m_instance = instance; m_loadedFromFile = false; } /** * <p>reload</p> * * @throws java.io.IOException if any. * @throws java.io.FileNotFoundException if any. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ public synchronized void reload() throws IOException, FileNotFoundException, MarshalException, ValidationException { m_instance = null; init(); } /** * Reload the http-datacollection-config.xml file if it has been changed since we last * read it. * * @throws java.io.IOException if any. * @throws org.exolab.castor.xml.MarshalException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ protected void updateFromFile() throws IOException, MarshalException, ValidationException { if (m_loadedFromFile) { File surveillanceViewsFile = ConfigFileConstants .getFile(ConfigFileConstants.HTTP_COLLECTION_CONFIG_FILE_NAME); if (m_lastModified != surveillanceViewsFile.lastModified()) { this.reload(); } } } /** * <p>getConfig</p> * * @return a {@link org.opennms.netmgt.config.httpdatacollection.HttpDatacollectionConfig} object. */ public synchronized static HttpDatacollectionConfig getConfig() { return m_config; } /** * <p>setConfig</p> * * @param m_config a {@link org.opennms.netmgt.config.httpdatacollection.HttpDatacollectionConfig} object. */ public synchronized static void setConfig(HttpDatacollectionConfig m_config) { HttpCollectionConfigFactory.m_config = m_config; } private ThreadCategory log() { return ThreadCategory.getInstance(); } /** * <p>getHttpCollection</p> * * @param collectionName a {@link java.lang.String} object. * @return a {@link org.opennms.netmgt.config.httpdatacollection.HttpCollection} object. */ public HttpCollection getHttpCollection(String collectionName) { List<HttpCollection> collections = m_config.getHttpCollectionCollection(); HttpCollection collection = null; for (HttpCollection coll : collections) { if (coll.getName().equalsIgnoreCase(collectionName)) { collection = coll; break; } } if (collection == null) { throw new IllegalArgumentException("getHttpCollection: collection name: " + collectionName + " specified in collectd configuration not found in http collection configuration."); } return collection; } /** * <p>getRrdRepository</p> * * @param collectionName a {@link java.lang.String} object. * @return a {@link org.opennms.netmgt.model.RrdRepository} object. */ public RrdRepository getRrdRepository(String collectionName) { RrdRepository repo = new RrdRepository(); repo.setRrdBaseDir(new File(getRrdPath())); repo.setRraList(getRRAList(collectionName)); repo.setStep(getStep(collectionName)); repo.setHeartBeat((2 * getStep(collectionName))); return repo; } /** * <p>getStep</p> * * @param cName a {@link java.lang.String} object. * @return a int. */ public int getStep(String cName) { HttpCollection collection = getHttpCollection(cName); if (collection != null) return collection.getRrd().getStep(); else return -1; } /** * <p>getRRAList</p> * * @param cName a {@link java.lang.String} object. * @return a {@link java.util.List} object. */ public List<String> getRRAList(String cName) { HttpCollection collection = getHttpCollection(cName); if (collection != null) return collection.getRrd().getRraCollection(); else return null; } /** * <p>getRrdPath</p> * * @return a {@link java.lang.String} object. */ public String getRrdPath() { String rrdPath = m_config.getRrdRepository(); if (rrdPath == null) { throw new RuntimeException("Configuration error, failed to " + "retrieve path to RRD repository."); } /* * TODO: make a path utils class that has the below in it strip the * File.separator char off of the end of the path. */ if (rrdPath.endsWith(File.separator)) { rrdPath = rrdPath.substring(0, (rrdPath.length() - File.separator.length())); } return rrdPath; } }