/*
    * 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.util;
  
  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.SQLException;
  import java.util.Properties;
  
  public class DriverManagerUtil {
    
    @SuppressWarnings("unchecked")
    public static Class loadDriver() throws ClassNotFoundException {
      String jdbcDriver = System.getenv("JDBC_DRIVER");
      if(jdbcDriver == null) {
        jdbcDriver = "com.mysql.jdbc.Driver";
      }
      return Class.forName(jdbcDriver);
    }
    
    public static Connection getConnection(String url) throws SQLException {
      ConnectionInfo info = new ConnectionInfo(url);
      return DriverManager.getConnection(info.getUri(), info.getProperties());
    }
    
    public static class ConnectionInfo {
      private Properties properties = new Properties();
      private String uri = null;
      
      public ConnectionInfo(String url) {
        int pos = url.indexOf('?');
        if(pos == -1) {
          uri = url;
        } else {
          uri = url.substring(0, pos);
          String[] paras = url.substring(pos + 1).split("&");
          for(String s : paras) {
            if(s==null || s.length()==0) {
              continue;
            }
            String[] kv = s.split("=");
            if(kv.length > 1) {
              properties.put(kv[0], kv[1]);
            }
            else {
              properties.put(kv[0], "");
            }
          }
        }
      }
  
      public Properties getProperties() {
        return properties;
      }
  
      public String getUri() {
        return uri;
      }
    }
  }