/*
    * 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 org.apache.hadoop.chukwa.extraction.engine.datasource;
  
  
  import java.util.HashMap;
  import org.apache.hadoop.chukwa.extraction.engine.datasource.database.DatabaseDS;
  import org.apache.hadoop.chukwa.extraction.engine.datasource.record.ChukwaRecordDataSource;
  
  public class DataSourceFactory {
    private static Object lock = new Object();
    private static DataSourceFactory factory = null;
    private HashMap<String, DataSource> dataSources = new HashMap<String, DataSource>();
  
    private DataSourceFactory() {
      // TODO load from config Name + class + threadSafe?
  
      DataSource databaseDS = new DatabaseDS();
      dataSources.put("MRJob", databaseDS);
      dataSources.put("HodJob", databaseDS);
      dataSources.put("QueueInfo", databaseDS);
  
    }
  
    public static DataSourceFactory getInstance() {
      synchronized (lock) {
        if (factory == null) {
          factory = new DataSourceFactory();
        }
      }
      return factory;
    }
  
    public DataSource getDataSource(String datasourceName)
        throws DataSourceException {
      if (dataSources.containsKey(datasourceName)) {
        return dataSources.get(datasourceName);
      } else {
        DataSource hsdfsDS = new ChukwaRecordDataSource();
        dataSources.put(datasourceName, hsdfsDS);
        return hsdfsDS;
        // TODO proto only!
        // throw new DataSourceException("Unknown datasource");
      }
    }
  }