package org.apache.torque.adapter;
   
   /*
    * 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.
   */
  
  import java.sql.Connection;
  import java.sql.SQLException;
  import java.sql.Statement;
  import java.text.SimpleDateFormat;
  import java.util.Date;
  
  import org.apache.torque.TorqueException;
  import org.apache.torque.util.Criteria;
  import org.apache.torque.util.Query;
  import org.apache.torque.util.SqlExpression;
  
  /***
   * This is used to connect to a Sybase database using Sybase's
   * JConnect JDBC driver.
   *
   * <B>NOTE:</B><I>Currently JConnect does not implement the required
   * methods for ResultSetMetaData, and therefore the village API's may
   * not function.  For connection pooling, everything works.</I>
   *
   * @author <a href="mailto:ekkerbj@netscape.net">Jeff Brekke</a>
   * @version $Id: DBSybase.java 586553 2007-10-19 17:33:53Z gmonroe $
   */
  public class DBSybase extends AbstractDBAdapter
  {
      /***
       * Serial version
       */
      private static final long serialVersionUID = 4782996646843056810L;
  
      /*** date format */
      private static final String DATE_FORMAT = "yyyyMMdd HH:mm:ss";
  
      /***
       * Empty constructor.
       */
      protected DBSybase()
      {
      }
  
      /***
       * This method is used to ignore case.
       *
       * @param in The string to transform to upper case.
       * @return The upper case string.
       */
      public String toUpperCase(String in)
      {
          return new StringBuffer("UPPER(").append(in).append(")").toString();
      }
  
      /***
       * This method is used to ignore case.
       *
       * @param in The string whose case to ignore.
       * @return The string in a case that can be ignored.
       */
      public String ignoreCase(String in)
      {
          return new StringBuffer("UPPER(").append(in).append(")").toString();
      }
  
      /***
       * @see org.apache.torque.adapter.DB#getIDMethodType()
       */
      public String getIDMethodType()
      {
          return AUTO_INCREMENT;
      }
  
      /***
       * Returns the last value from an identity column (available on a
       * per-session basis from the global variable
       * <code>@@identity</code>).
       *
       * @see org.apache.torque.adapter.DB#getIDMethodSQL(Object obj)
       */
      public String getIDMethodSQL(Object unused)
      {
         return "select @@identity";
     }
 
     /***
      * Locks the specified table.
      *
      * @param con The JDBC connection to use.
      * @param table The name of the table to lock.
      * @throws SQLException No Statement could be created or executed.
      */
     public void lockTable(Connection con, String table) throws SQLException
     {
         Statement statement = con.createStatement();
 
         StringBuffer stmt = new StringBuffer();
         stmt.append("SELECT next_id FROM ")
         .append(table)
         .append(" FOR UPDATE");
 
         statement.executeQuery(stmt.toString());
     }
 
     /***
      * Unlocks the specified table.
      *
      * @param con The JDBC connection to use.
      * @param table The name of the table to unlock.
      * @throws SQLException No Statement could be created or executed.
      */
     public void unlockTable(Connection con, String table) throws SQLException
     {
         // Tables in Sybase are unlocked when a commit is issued.  The
         // user may have issued a commit but do it here to be sure.
         con.commit();
     }
 
     /***
      * This method is used to chek whether the database supports
      * limiting the size of the resultset.
      *
      * @return LIMIT_STYLE_SYBASE.
      * @deprecated This should not be exposed to the outside
      */
     public int getLimitStyle()
     {
         return DB.LIMIT_STYLE_SYBASE;
     }
 
     /***
      * Return true for Sybase
      * @see org.apache.torque.adapter.AbstractDBAdapter#supportsNativeLimit()
      */
     public boolean supportsNativeLimit()
     {
         return true;
     }
 
     /***
      * Modify a query to add limit and offset values for Sybase.
      *
      * @param query The query to modify
      * @param offset the offset Value
      * @param limit the limit Value
      *
      * @throws TorqueException if any error occurs when building the query
      */
     public void generateLimits(Query query, int offset, int limit)
         throws TorqueException
     {
         if ( limit < 0 && offset >= 0 ) // Offset only test
         {
             return;
         }
         if (limit + offset > 0)
         {
             query.setRowcount(String.valueOf(limit + offset));
         }
         else if (limit + offset == 0)
         {
             // This is necessary to create the empty result set that Torque expects
             query.getWhereClause().add(SqlExpression.build("1", new Integer(0), Criteria.EQUAL));
         }
     }
 
     /***
      * This method overrides the JDBC escapes used to format dates
      * using a <code>DateFormat</code>.  As of version 11, the Sybase
      * JDBC driver does not implement JDBC 3.0 escapes.
      *
      * @param date the date to format
      * @return The properly formatted date String.
      */
     public String getDateString(Date date)
     {
         char delim = getStringDelimiter();
         return (delim + new SimpleDateFormat(DATE_FORMAT).format(date) + delim);
     }
 
     /***
      * Determines whether backslashes (\) should be escaped in explicit SQL
      * strings. If true is returned, a BACKSLASH will be changed to "//".
      * If false is returned, a BACKSLASH will be left as "\".
      *
      * Sybase (and MSSQL) doesn't define a default escape character,
      * so false is returned.
      *
      * @return false
      * @see org.apache.torque.adapter.DB#escapeText()
      */
     public boolean escapeText()
     {
         return false;
     }
 
     /***
      * Whether an escape clause in like should be used.
      * Example : select * from AUTHOR where AUTHOR.NAME like '\_%' ESCAPE '\';
      *
      * Sybase needs this, so this implementation always returns
      * <code>true</code>.
      *
      * @return whether the escape clause should be appended or not.
      */
     public boolean useEscapeClauseForLike()
     {
         return true;
     }
 }