/**

  * Copyright 2013 Sven Diedrichsen 

  * 

  * Licensed 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 de.jollyday.datasource;

 import de.jollyday.ManagerParameter;

 import de.jollyday.util.ClassLoadingUtil;

 /**

  * This manager is responsible for instantiating the configured configuration datasource

  * which is used to access the holiday data.

  * 

  * @author sdiedrichsen

  */

 public class ConfigurationDataSourceManager {

         private ClassLoadingUtil classLoadingUtil = new ClassLoadingUtil();

         public ConfigurationDataSource getConfigurationDataSource(ManagerParameter parameter){

                 validateConfiguration(parameter);

                 String dataSourceClassName = parameter.getProperty(ManagerParameter.CONFIGURATION_DATASOURCE_IMPL_CLASS);

                 return instantiateDataSource(dataSourceClassName);

         }

         private ConfigurationDataSource instantiateDataSource(

                         String dataSourceClassName) {

                 try{

                         Class<?> dataSourceClass = classLoadingUtil.getClassloader().loadClass(dataSourceClassName);

                         return ConfigurationDataSource.class.cast(dataSourceClass.newInstance());

                 }catch(Exception e){

                         throw new IllegalStateException("Cannot instantiate datasource instance of "+dataSourceClassName,e);

                 }

         }

         private void validateConfiguration(ManagerParameter parameter) {

                 if(parameter.getProperty(ManagerParameter.CONFIGURATION_DATASOURCE_IMPL_CLASS) == null){

                         throw new IllegalStateException("Missing holiday configuration datasource implementation class under config key "+ManagerParameter.CONFIGURATION_DATASOURCE_IMPL_CLASS);

                 }

         }

 }