package com.explosion.expfmodules.rdbmsconn.dbom.dialect;
   
   import java.sql.DatabaseMetaData;
   import java.sql.SQLException;
   import org.apache.log4j.LogManager;
   import org.apache.log4j.Logger;
   import com.explosion.expfmodules.rdbmsconn.dbom.DBEntity;
   import com.explosion.expfmodules.rdbmsconn.dbom.utils.MetadataException;
   
  /*
   * =============================================================================
   * 
   * Copyright 2004 Stephen Cowx
   * 
   * 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.
   * 
   * =============================================================================
   */
  /***
   * I have to be honest, this is exactly the same concept as the hibernate dialect.
   * Haven't stolen the actual code (YET!).  May do at a later stage.
   * 
   * For now this is just a moving in the same directio because it is a sensible idea
   * to support the variations in platform.  I guess I will extend it at a later stage.
   * 
   * @author Stephen
   * Created on 24-May-2005
   */
  public class Dialect
  {
      private static Logger log = LogManager.getLogger(Dialect.class);
      
      private static String[] escapeMeCharacters = { " ", "\'"};
      
      /***
       * This method returns the correct identifier for an sql statement against the connected database.
       * This may be fully qualified. Entity names and schema/ctalog names are prepared using the prepareName 
       * method.  Entity names are delimited from the schema's ,catalogs etc with the relevant schema or 
       * catalog separator for the connected database.
       * @throws MetadataException
       * @throws SQLException
       */
      public String getFullEntityName(DBEntity dbed, DatabaseMetaData meta) throws SQLException, MetadataException
      {
          String entityName = dbed.getEntityName();
          String schemaName = dbed.getSchemaName();
          String catalogName = dbed.getCatalogName();
          String separator = ".";
          
          /* Do the catalog */
          if (catalogName != null)
          {
              if (meta.supportsCatalogsInTableDefinitions())
              {
                  catalogName = prepareName(catalogName, meta);
                  separator = meta.getCatalogSeparator(); 
              }
          }
          
          /* Do the schema */
          if (schemaName != null)
          {
              if (meta.supportsSchemasInTableDefinitions())
              {
                  schemaName = prepareName(schemaName, meta);
              }            
          }
  
          /* Do the entity */
          if (entityName != null)
              entityName = prepareName(entityName, meta);
  
          /* Do a check */
          if (schemaName != null && catalogName != null)
              throw new MetadataException("Interesting!  This database has schema's and catalogs.  Please log this as a bug and provide full details of your database platform.  Thanks.");
  
          /* Do the business */
          if (schemaName != null)
              return schemaName + (schemaName.trim().length() > 0 ? separator : "") + entityName;
          else if (catalogName != null)
              return catalogName + (catalogName.trim().length() > 0 ? separator : "") + entityName;
          else
              return prepareName(entityName, meta);
      }
  
      /***
       * This method returns a fully qualified column name given the name and a
       * identifier (tablename or whatever). 
       * 
      * Names are prepared using the prepareName method and are delimited from
      * the identifier with a with a point (.) if the identifier is not null and not an empty string
      * @throws SQLException
      */
     public String getFullColumnName(String columnName, String identifier, DatabaseMetaData meta) throws SQLException
     {
         /* Do the identifier */
         if (identifier != null)
             identifier = prepareName(identifier, meta);
 
         /* Do the entity */
         if (columnName != null)
             columnName = prepareName(columnName, meta);
 
         /* Do the business */
         if (identifier != null)
             return identifier + (identifier.trim().length() > 0 ? "." : "") + columnName;
         else
             return columnName;
     }
 
     /***
      * This takes an entity name and prepares it for use in an sql statement
      * accordng to the rulews defined by the jdbc driver for entity names.
      * If the names need to be in quotes it will be placed in quotes.
      * If the identifiers are stored in the database in upper/lower/mixed case the name will be adjusted accordingly
      * 
      * If the name contains one of the escapeMeCharacters, sorround it with [
      * and ].  The scape characters are a space or a single quote
      * 
      * @param name
      * @return
      * @throws SQLException
      */
     public String prepareName(String name, DatabaseMetaData meta) throws SQLException
     {
         //Check the obvious
         if (name == null)
             return null;
         
         //Upper lower mixed
         String preparedName = null;
         if (meta.storesLowerCaseIdentifiers()) 
         {
             preparedName = name.toLowerCase();  
         } 
         else if (meta.storesUpperCaseIdentifiers()) 
         {
             preparedName = name.toUpperCase();
         } 
         else 
         {
             preparedName = name;
         }
         
         //Quotes
 //        if (meta.storesLowerCaseQuotedIdentifiers())
 //        {
 //            log.debug("1");
 //        }
 //        else if (meta.storesUpperCaseQuotedIdentifiers())
 //        {
 //            log.debug("2");
 //        }
 //        else if (meta.storesMixedCaseQuotedIdentifiers())
 //        {
 //            log.debug("3");   
 //        }
         
         for (int i = 0; i < escapeMeCharacters.length; i++)
         {
             if (preparedName.trim().indexOf(escapeMeCharacters[i]) >= 0)
                 return "[" + preparedName.trim() + "]";
         }
         return preparedName;
     }
     
     /***
      * Returns true if the DB supports transactions and savepoints.
      * @return
      */
     public boolean supportsCommitAndRollback()
     {
     	return true;
     }
     
     /***
      * Returns true if the DB supports transactions and savepoints.
      * @return
      */
     public boolean supportsSavePoints()
     {
     	return false;
     }
 }