/*
    * 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.indexOf(POSTGRES_PART) != -1) {
          return ConnectionSource.POSTGRES_DIALECT;
        } else if (dbName.indexOf(MYSQL_PART) != -1) {
          return ConnectionSource.MYSQL_DIALECT;
        } else if (dbName.indexOf(ORACLE_PART) != -1) {
          return ConnectionSource.ORACLE_DIALECT;
        } else if (dbName.indexOf(MSSQL_PART) != -1) {
          return ConnectionSource.MSSQL_DIALECT;
        } else if (dbName.indexOf(HSQL_PART) != -1) {
          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 {
       //
       //   invoking JDK 1.4 method by reflection
       //
       return ((Boolean) DatabaseMetaData.class.getMethod("supportsGetGeneratedKeys", null).invoke(meta, null)).booleanValue();
     } 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;
     }
   }
 }