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.StringWriter; import java.io.Writer; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.HashMap; import java.util.Map; import org.apache.commons.io.IOUtils; import org.exolab.castor.xml.MarshalException; import org.exolab.castor.xml.Marshaller; 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.threshd.Basethresholddef; import org.opennms.netmgt.config.threshd.Group; import org.opennms.netmgt.config.threshd.ThresholdingConfig; /** * This class is the main repository for thresholding configuration information * used by the thresholding daemon.. When this class is loaded it reads the * thresholding configuration into memory. * * <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:mike@opennms.org">Mike Davidson </a> * @author <a href="http://www.opennms.org/">OpenNMS </a> * @author <a href="mailto:mike@opennms.org">Mike Davidson </a> * @author <a href="http://www.opennms.org/">OpenNMS </a> * @version $Id: $ */ public final class ThresholdingConfigFactory { /** * The singleton instance of this factory */ private static ThresholdingConfigFactory m_singleton = null; /** * The config class loaded from the config file */ private ThresholdingConfig m_config; /** * This member is set to true if the configuration file has been loaded. */ private static boolean m_loaded = false; /** * Map of org.opennms.netmgt.config.threshd.Group objects indexed by group * name. */ private Map<String, Group> m_groupMap; /** * Private constructor * * @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. */ private ThresholdingConfigFactory(String configFile) throws IOException, MarshalException, ValidationException { InputStream stream = null; try { stream = new FileInputStream(configFile); parseXML(stream); } finally { if (stream != null) { IOUtils.closeQuietly(stream); } } } /** * <p>Constructor for ThresholdingConfigFactory.</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 ThresholdingConfigFactory(InputStream stream) throws MarshalException, ValidationException { parseXML(stream); } private void parseXML(InputStream stream) throws MarshalException, ValidationException { m_config = CastorUtils.unmarshal(ThresholdingConfig.class, stream); initGroupMap(); } /** * Build map of org.opennms.netmgt.config.threshd.Group objects * indexed by group name. * * This is parsed and built at initialization for * faster processing at run-timne. */ private void initGroupMap() { Map<String, Group> groupMap = new HashMap<String, Group>(); for (Group g : m_config.getGroupCollection()) { groupMap.put(g.getName(), g); } m_groupMap = groupMap; } /** * 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; } File cfgFile = ConfigFileConstants.getFile(ConfigFileConstants.THRESHOLDING_CONF_FILE_NAME); if (log().isDebugEnabled()) { log().debug("init: config file path: " + cfgFile.getPath()); } ThresholdingConfigFactory tcf = new ThresholdingConfigFactory(cfgFile.getPath()); for (String groupName : tcf.getGroupNames()) { Group g = tcf.getGroup(groupName); for (org.opennms.netmgt.config.threshd.Threshold threshold : g.getThresholdCollection()) { if (threshold.getDsName().length() > ConfigFileConstants.RRD_DS_MAX_SIZE) { throw new ValidationException( String.format("ds-name '%s' in group '%s' is greater than %d characters", threshold.getDsName(), groupName, ConfigFileConstants.RRD_DS_MAX_SIZE)); } } } m_singleton = tcf; m_loaded = true; } /** * 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(); } /** * 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 ThresholdingConfigFactory getInstance() { if (!m_loaded) { throw new IllegalStateException("The factory has not been initialized"); } return m_singleton; } /** * <p>setInstance</p> * * @param instance a {@link org.opennms.netmgt.config.ThresholdingConfigFactory} object. */ public static synchronized void setInstance(ThresholdingConfigFactory instance) { m_loaded = true; m_singleton = instance; } /** * Retrieves the configured path to the RRD file repository for the * specified thresholding group. * * @param groupName * Group name to lookup * @return RRD repository path. * @throws java.lang.IllegalArgumentException * if group name does not exist in the group map. */ public String getRrdRepository(String groupName) { return getGroup(groupName).getRrdRepository(); } /** * <p>getGroup</p> * * @param groupName a {@link java.lang.String} object. * @return a {@link org.opennms.netmgt.config.threshd.Group} object. */ public Group getGroup(String groupName) { Group group = m_groupMap.get(groupName); if (group == null) { throw new IllegalArgumentException("Thresholding group " + groupName + " does not exist."); } return group; } /** * Retrieves a Collection object consisting of all the * org.opennms.netmgt.config.Threshold objects which make up the specified * thresholding group. * * @param groupName * Group name to lookup * @return Collection consisting of all the Threshold objects for the * specified group.. * @throws java.lang.IllegalArgumentException * if group name does not exist in the group map. */ public Collection<Basethresholddef> getThresholds(String groupName) { Group group = getGroup(groupName); Collection<Basethresholddef> result = new ArrayList<Basethresholddef>(); result.addAll(group.getThresholdCollection()); result.addAll(group.getExpressionCollection()); return result; } /** * <p>getGroupNames</p> * * @return a {@link java.util.Collection} object. */ public Collection<String> getGroupNames() { return Collections.unmodifiableCollection(m_groupMap.keySet()); } /** * Saves the current in-memory configuration to disk and reloads * * @throws org.exolab.castor.xml.MarshalException if any. * @throws java.io.IOException if any. * @throws org.exolab.castor.xml.ValidationException if any. */ public synchronized void saveCurrent() throws MarshalException, IOException, ValidationException { // Marshal to a string first, then write the string to the file. This // way the original config // isn't lost if the XML from the marshal is hosed. StringWriter stringWriter = new StringWriter(); Marshaller.marshal(m_config, stringWriter); String xmlString = stringWriter.toString(); if (xmlString != null) { File cfgFile = ConfigFileConstants.getFile(ConfigFileConstants.THRESHOLDING_CONF_FILE_NAME); Writer fileWriter = new OutputStreamWriter(new FileOutputStream(cfgFile), "UTF-8"); fileWriter.write(xmlString); fileWriter.flush(); fileWriter.close(); } update(); } /** * <p>update</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 update() throws IOException, MarshalException, ValidationException { File cfgFile = ConfigFileConstants.getFile(ConfigFileConstants.THRESHOLDING_CONF_FILE_NAME); InputStream stream = null; try { stream = new FileInputStream(cfgFile); parseXML(stream); } finally { if (stream != null) { IOUtils.closeQuietly(stream); } } } private static ThreadCategory log() { return ThreadCategory.getInstance(ThresholdingConfigFactory.class); } }