Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package eagle.storage; import eagle.common.config.EagleConfigFactory; import eagle.storage.spi.DataStorageServiceLoader; import eagle.storage.exception.IllegalDataStorageTypeException; import eagle.storage.spi.DataStorageServiceProvider; import org.apache.commons.configuration.Configuration; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.util.Properties; /** * @since 3/20/15 */ public class DataStorageManager { public final static String EAGLE_STORAGE_TYPE = "eagle.service.storage-type"; public final static String DEFAULT_DATA_STORAGE_TYPE = "hbase"; private final static Logger LOG = LoggerFactory.getLogger(DataStorageManager.class); /** * Get data storage without cache * * @param type * @throws IllegalDataStorageTypeException */ public static DataStorage newDataStorage(String type) throws IllegalDataStorageTypeException { DataStorageServiceProvider serviceProvider = DataStorageServiceLoader.getInstance() .getStorageProviderByType(type); if (serviceProvider == null) { throw new IllegalDataStorageTypeException("data storage provider of type: " + type + " is null"); } DataStorage dataStorage = serviceProvider.getStorage(); try { LOG.info("Initializing data storage engine: " + dataStorage); dataStorage.init(); } catch (IOException e) { LOG.error("Failed to initialize data storage engine " + dataStorage, e); throw new IllegalStateException(e); } return dataStorage; } private static DataStorage singletonStorageInstance; /** * get storage class by type configured as eagle.storage.type from eagle configuration: config.properties * * @return DataStorage instance * * @throws IllegalDataStorageTypeException */ public static DataStorage getDataStorageByEagleConfig(boolean cache) throws IllegalDataStorageTypeException { String storageType = EagleConfigFactory.load().getStorageType(); if (!cache) return newDataStorage(storageType); if (singletonStorageInstance == null) { if (storageType == null) { LOG.error( EAGLE_STORAGE_TYPE + " is null, trying default data storage: " + DEFAULT_DATA_STORAGE_TYPE); storageType = DEFAULT_DATA_STORAGE_TYPE; } singletonStorageInstance = newDataStorage(storageType); } return singletonStorageInstance; } /** * @return DataStorage instance by singleton pattern * * @throws IllegalDataStorageTypeException */ public static DataStorage getDataStorageByEagleConfig() throws IllegalDataStorageTypeException { return getDataStorageByEagleConfig(true); } /** * Get data storage by configuration * * @param configuration * @return * @throws IllegalDataStorageTypeException */ public static DataStorage newDataStorage(Configuration configuration) throws IllegalDataStorageTypeException { String storageType = configuration.getString(EAGLE_STORAGE_TYPE); if (storageType == null) { throw new IllegalDataStorageTypeException(EAGLE_STORAGE_TYPE + " is null"); } return newDataStorage(storageType); } /** * Get data storage by properties * * @param properties * @return * @throws IllegalDataStorageTypeException */ public static DataStorage newDataStorage(Properties properties) throws IllegalDataStorageTypeException { String storageType = (String) properties.get(EAGLE_STORAGE_TYPE); if (storageType == null) { LOG.error(EAGLE_STORAGE_TYPE + " is null"); throw new IllegalDataStorageTypeException(EAGLE_STORAGE_TYPE + " is null"); } return newDataStorage(storageType); } }