Java tutorial
/******************************************************************************* * Copyright (c) 2010-2014 SAP AG and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * SAP AG - initial API and implementation *******************************************************************************/ package org.eclipse.skalli.core.configuration; import java.io.ByteArrayInputStream; import java.io.InputStream; import java.io.UnsupportedEncodingException; import java.text.MessageFormat; import java.util.Collections; import java.util.List; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import org.apache.commons.io.IOUtils; import org.eclipse.skalli.commons.ThreadPool; import org.eclipse.skalli.core.storage.FileStorageComponent; import org.eclipse.skalli.core.xstream.CompositeEntityClassLoader; import org.eclipse.skalli.services.BundleProperties; import org.eclipse.skalli.services.configuration.ConfigSection; import org.eclipse.skalli.services.configuration.ConfigurationService; import org.eclipse.skalli.services.configuration.EventConfigUpdate; import org.eclipse.skalli.services.event.EventService; import org.eclipse.skalli.services.permit.Permits; import org.eclipse.skalli.services.persistence.StorageException; import org.eclipse.skalli.services.persistence.StorageService; import org.osgi.service.component.ComponentConstants; import org.osgi.service.component.ComponentContext; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.thoughtworks.xstream.XStream; import com.thoughtworks.xstream.XStreamException; public class ConfigurationComponent implements ConfigurationService { private static final Logger LOG = LoggerFactory.getLogger(ConfigurationComponent.class); private static final Logger AUDIT_LOG = LoggerFactory.getLogger("audit"); //$NON-NLS-1$ private static final String CATEGORY_CUSTOMIZATION = "customization"; //$NON-NLS-1$ private EventService eventService; private StorageService storageService; private String storageServiceClassName; private Map<String, ConfigSection<?>> byStorageKey = new ConcurrentHashMap<String, ConfigSection<?>>(); private Map<Class<?>, ConfigSection<?>> byConfigClass = new ConcurrentHashMap<Class<?>, ConfigSection<?>>(); private static Map<Class<?>, Object> configCache = new ConcurrentHashMap<Class<?>, Object>(); public ConfigurationComponent() { storageServiceClassName = BundleProperties.getProperty(BundleProperties.PROPERTY_STORAGE_SERVICE, FileStorageComponent.class.getName()); } // Constructor for testing purposes. // Set the storage services to use with bindStorageService(). ConfigurationComponent(String storageServiceClassName) { this.storageServiceClassName = storageServiceClassName; } protected void activate(ComponentContext context) { LOG.info(MessageFormat.format("[ConfigurationService] {0} : activated", //$NON-NLS-1$ (String) context.getProperties().get(ComponentConstants.COMPONENT_NAME))); } protected void deactivate(ComponentContext context) { LOG.info(MessageFormat.format("[ConfigurationService] {0} : deactivated", //$NON-NLS-1$ (String) context.getProperties().get(ComponentConstants.COMPONENT_NAME))); } protected void bindEventService(EventService eventService) { this.eventService = eventService; LOG.info(MessageFormat.format("bindEventService({0})", eventService)); //$NON-NLS-1$ } protected void unbindEventService(EventService eventService) { LOG.info(MessageFormat.format("unbindEventService({0})", eventService)); //$NON-NLS-1$ this.eventService = null; } protected void bindStorageService(StorageService storageService) { if (storageServiceClassName.equals(storageService.getClass().getName())) { this.storageService = storageService; configCache.clear(); notifyCustomizationChanged(storageService); LOG.info(MessageFormat.format("bindStorageService({0})", storageService)); //$NON-NLS-1$ } } protected void unbindStorageService(StorageService storageService) { if (storageServiceClassName.equals(storageService.getClass().getName())) { LOG.info(MessageFormat.format("unbindStorageService({0})", storageService)); //$NON-NLS-1$ this.storageService = null; configCache.clear(); notifyCustomizationChanged(storageService); } } protected void bindConfigSection(ConfigSection<?> configSection) { byConfigClass.put(configSection.getConfigClass(), configSection); byStorageKey.put(configSection.getStorageKey(), configSection); configCache.remove(configSection.getConfigClass()); notifyCustomizationChanged(configSection); LOG.info(MessageFormat.format("bindConfigSection({0})", configSection)); //$NON-NLS-1$ } protected void unbindConfigSection(ConfigSection<?> configSection) { LOG.info(MessageFormat.format("unbindConfigSection({0})", configSection)); //$NON-NLS-1$ byConfigClass.remove(configSection.getConfigClass()); byStorageKey.remove(configSection.getStorageKey()); configCache.remove(configSection.getConfigClass()); notifyCustomizationChanged(configSection); } ConfigSection<?> getConfigSection(Class<?> configClass) { return byConfigClass.get(configClass); } ConfigSection<?> getConfigSection(String storageKey) { return byStorageKey.get(storageKey); } @Override public synchronized <T> void writeConfiguration(T configuration) { if (storageService == null) { LOG.error("Cannot store configurations: StorageService not available"); return; } if (configuration == null) { // delete configuration? return; } ConfigSection<?> configSection = byConfigClass.get(configuration.getClass()); if (configSection == null) { LOG.error(MessageFormat.format("Cannot store configuration: No suitable configuration extension " + //$NON-NLS-1$ "for configurations of type ''{0}'' available", //$NON-NLS-1$ configuration.getClass())); return; } String storageKey = configSection.getStorageKey(); Class<?> configurationClass = configuration.getClass(); String xml = getXStream(configurationClass).toXML(configuration); InputStream is = null; try { is = new ByteArrayInputStream(xml.getBytes("UTF-8")); //$NON-NLS-1$ storageService.write(CATEGORY_CUSTOMIZATION, storageKey, is); configCache.put(configurationClass, configuration); if (eventService != null) { fireEvent(configSection, configuration); } AUDIT_LOG.info(MessageFormat.format("Configuration ''{0}'' changed by user ''{1}''", storageKey, Permits.getLoggedInUser())); } catch (UnsupportedEncodingException e) { // should never happen for UTF-8 throw new IllegalStateException(e); } catch (StorageException e) { LOG.error(MessageFormat.format("Failed to store configuration ''{0}''", storageKey), e); } finally { IOUtils.closeQuietly(is); } }; @Override public synchronized <T> T readConfiguration(Class<T> configurationClass) { if (storageService == null) { LOG.warn("Cannot load configurations: StorageService not available"); return null; } if (configurationClass == null) { return null; } Object config = configCache.get(configurationClass); if (config == null) { ConfigSection<?> configSection = byConfigClass.get(configurationClass); if (configSection == null) { LOG.error( MessageFormat.format("Cannot retrieve configuration: No suitable configuration extension " + //$NON-NLS-1$ "for configurations of type ''{0}'' available", //$NON-NLS-1$ configurationClass)); return null; } config = readConfiguration(configSection.getStorageKey(), configurationClass); } return configurationClass.cast(config); } private Object readConfiguration(String storageKey, Class<?> configurationClass) { Object config = null; InputStream is = null; try { is = storageService.read(CATEGORY_CUSTOMIZATION, storageKey); if (is == null) { return null; } config = getXStream(configurationClass).fromXML(is); } catch (XStreamException e) { LOG.error(MessageFormat.format("Failed to unmarshal configuration ''{0}'' ", storageKey), e); } catch (StorageException e) { LOG.error(MessageFormat.format("Failed to retrieve configuration ''{0}''", storageKey), e); } finally { IOUtils.closeQuietly(is); } return config; } private XStream getXStream(Class<?> customizationClass) { XStream xstream = new XStream(); ClassLoader classLoader = customizationClass.getClassLoader(); if (classLoader != null) { xstream.setClassLoader(new CompositeEntityClassLoader(Collections.singleton(classLoader))); } return xstream; } private void notifyCustomizationChanged(final StorageService storageService) { ThreadPool.submit(new Runnable() { @Override public void run() { if (eventService != null) { List<String> storageKeys = Collections.emptyList(); try { storageKeys = storageService.keys(CATEGORY_CUSTOMIZATION); } catch (StorageException e) { LOG.error("Failed to retrieve configuration keys", e); return; } for (String storageKey : storageKeys) { ConfigSection<?> configSection = byStorageKey.get(storageKey); if (configSection != null) { fireEvent(configSection); } } } } }); } private void notifyCustomizationChanged(final ConfigSection<?> configSection) { ThreadPool.submit(new Runnable() { @Override public void run() { if (eventService != null && storageService != null) { fireEvent(configSection); } } }); } private void fireEvent(ConfigSection<?> configSection) { Object config = readConfiguration(configSection.getStorageKey(), configSection.getConfigClass()); fireEvent(configSection, config); } private void fireEvent(ConfigSection<?> configSection, Object config) { eventService.fireEvent(new EventConfigUpdate(configSection.getConfigClass(), config)); LOG.info(MessageFormat.format("Event sent: Configuration ''{0}'' has changed", configSection.getConfigClass().getSimpleName())); } }