/*
    * 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.log4j.db.dialect;
  
  import org.apache.log4j.db.ConnectionSource;
  import org.apache.log4j.spi.ComponentBase;
  
  import java.sql.DatabaseMetaData;
  import java.sql.SQLException;
  
  
  /**
   * @author Ceki Gulcu
   */
  public class Util extends ComponentBase {
      private static final String POSTGRES_PART = "postgresql";
      private static final String MYSQL_PART = "mysql";
      private static final String ORACLE_PART = "oracle";
      //private static final String MSSQL_PART = "mssqlserver4";
      private static final String MSSQL_PART = "microsoft";
      private static final String HSQL_PART = "hsql";
  
      public static int discoverSQLDialect(DatabaseMetaData meta) {
          int dialectCode = 0;
  
          try {
  
              String dbName = meta.getDatabaseProductName().toLowerCase();
  
              if (dbName.contains(POSTGRES_PART)) {
                  return ConnectionSource.POSTGRES_DIALECT;
              } else if (dbName.contains(MYSQL_PART)) {
                  return ConnectionSource.MYSQL_DIALECT;
              } else if (dbName.contains(ORACLE_PART)) {
                  return ConnectionSource.ORACLE_DIALECT;
              } else if (dbName.contains(MSSQL_PART)) {
                  return ConnectionSource.MSSQL_DIALECT;
              } else if (dbName.contains(HSQL_PART)) {
                  return ConnectionSource.HSQL_DIALECT;
              } else {
                  return ConnectionSource.UNKNOWN_DIALECT;
              }
          } catch (SQLException sqle) {
              // we can't do much here
          }
  
          return dialectCode;
      }
  
      public static SQLDialect getDialectFromCode(int dialectCode) {
          SQLDialect sqlDialect = null;
  
          switch (dialectCode) {
              case ConnectionSource.POSTGRES_DIALECT:
                  sqlDialect = new PostgreSQLDialect();
  
                  break;
              case ConnectionSource.MYSQL_DIALECT:
                  sqlDialect = new MySQLDialect();
  
                  break;
              case ConnectionSource.ORACLE_DIALECT:
                  sqlDialect = new OracleDialect();
  
                  break;
              case ConnectionSource.MSSQL_DIALECT:
                  sqlDialect = new MsSQLDialect();
  
                  break;
              case ConnectionSource.HSQL_DIALECT:
                  sqlDialect = new HSQLDBDialect();
  
                  break;
          }
          return sqlDialect;
      }
  
      /**
       * This method handles cases where the
       * {@link DatabaseMetaData#supportsGetGeneratedKeys} method is missing in the
       * JDBC driver implementation.
       */
      public boolean supportsGetGeneratedKeys(DatabaseMetaData meta) {
          try {
             return meta.supportsGetGeneratedKeys();
         } catch (Throwable e) {
             getLogger().info("Could not call supportsGetGeneratedKeys method. This may be recoverable");
             return false;
         }
     }
 
     /**
      * This method handles cases where the
      * {@link DatabaseMetaData#supportsBatchUpdates} method is missing in the
      * JDBC driver implementation.
      */
     public boolean supportsBatchUpdates(DatabaseMetaData meta) {
         try {
             return meta.supportsBatchUpdates();
         } catch (Throwable e) {
             getLogger().info("Missing DatabaseMetaData.supportsBatchUpdates method.");
             return false;
         }
     }
 }