Metacat

  public static synchronized boolean shrinkConnectionPoolSize() 

     boolean hasException = false; //to check if has a exception happend

     boolean result = false; //result

     DBConnection conn = null; // the dbconnection

     MetaCatUtil.debugMessage("Connection pool size: " +connectionPoolSize, 3);

     MetaCatUtil.debugMessage("Free Connection number: "+freeConnectionSize, 3);

       //db connection having index from  to connectionpoolsize -1

       //intialConnectionnumber should be close and remove from pool

       for ( int i=connectionPoolSize-1; i >= INITIALCONNECTIONNUMBER ; i--)

           //close conn

         { 

           // set hadException ture

           hasException = true;

           MetaCatUtil.debugMessage("Couldn't close a DBConnection in " +

                            "DBConnectionPool.shrinkDBConnectionPoolSize: " +

                            e.getMessage(), 30);

        //remove it from pool

        connectionPool.remove(i);

        // becuase enter the loop, set result true

        result = true;

     //if hasException is true ( there at least once exception happend)

     // the result should be false

     if (hasException)

     {

       result =false;

     }//if

     // return result

     return result;

    /**

   * Method to decrease dbconnection pool size when all dbconnections are idle

   * If all connections are free and connection pool size greater than 

   * initial value, shrink connection pool size to intital value

   */

  public static synchronized void shrinkDBConnectionPoolSize() 

  {

     int connectionPoolSize = 0; //store the number of dbconnection pool size

     int freeConnectionSize = 0; //store the number of free dbconnection in pool

     int difference = 0; // store the difference number between connection size

                         // and free connection

     DBConnection conn = null; // the dbconnection

     connectionPoolSize = connectionPool.size();

     freeConnectionSize = getFreeDBConnectionNumber();

     MetaCatUtil.debugMessage("Connection pool size: " +connectionPoolSize, 3);

     MetaCatUtil.debugMessage("Free Connection number: "+freeConnectionSize, 3);

     difference = connectionPoolSize - freeConnectionSize;

     //If all connections are free and connection pool size greater than 

     //initial value, shrink connection pool size to intital value

     if (difference == 0 && connectionPoolSize > INITIALCONNECTIONNUMBER)

     {

       //db connection having index from  to connectionpoolsize -1

       //intialConnectionnumber should be close and remove from pool

       for ( int i=connectionPoolSize-1; i >= INITIALCONNECTIONNUMBER ; i--)

       {

         //get the dbconnection from pool

         conn = (DBConnection) connectionPool.elementAt(i);

         //make sure again the DBConnection status is free

         if (conn.getStatus()==FREE)

         {

           try

           {

             //close conn

             conn.close();

           }//try

           catch (SQLException e)

           { 

             MetaCatUtil.debugMessage("Couldn't close a DBConnection in " +

                            "DBConnectionPool.shrinkDBConnectionPoolSize: " +

                            e.getMessage(), 30);

           }//catch

           //remove it from pool

           connectionPool.remove(i);

         }//if

       }//for

     }//if

  }//shrinkDBConnectionPoolSize