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Message:

abstract factories

Posted by Chin Loong on January 23, 2002 at 6:03 AM

this is exactly how it was done in my previous company.

i was just beginning to learn java at the time, so it was really a hell trying to catch up. anyway, the structure is something like this : (not really sure coz i can't really remember, and i didn't really catch up at this part too... :p too busy learning servlets and jsp at that time.)

public class DataManager
{
    // initializes database driver if not already initialized
    // obtains connection and etc.
}

i.e. if we were supposed to access data from table [customer]

public abstract class AbstractCustomer extends DataManager
{
    public static Customer findByPrimaryKey(int id);
    // etc etc
}
public class DB2CustomerDM extends AbstractCustomer // for DB2
{
    public static Customer findByPrimaryKey(int id)
    {
        // obtains connection and sends SELECT query to db2
    }
}
public class MYSQLCustomerDM extends AbstractCustomer // mySQL
{
    public static Customer findByPrimaryKey(int id)
    {
        // obtains connection and sends SELECT query to mysql
    }
}

during execution :

public void someMethod(int id)
{
    String dbFactory = // read from properties file that might contain
                       // values like Customer=com.company.database.MYSQLCustomerDB
                       // and subsitute the value into the string
    AbstractCustomer aCustomer=(AbstractCustomer)Class.forName(dbFactory).newInstance();
    Customer customer=aCustomer.findByPrimaryKey(id);
    ...
    ...
}

so there'll be a properties file or rather, an LDAP server that matches the list of database tables with the correct factory.

or something like that.. this is from what i barely remembered during my 3-month internship there. massive learning at that time.. didn't get to catch up on this concept. caught up on jsp and servlets though :p

anyway, they got some kind of horizontal framework that they later extend into vertical framework for the community portal products that they make. marketing stuff :p

• Database migration Jay January 23, 2002 at 5:14 PM (2)
  • Comments anyone? ...EOM Jay January 25, 2002 at 1:47 PM (1)
    • Abstract Factories vs. Abstract Methods Matt Gerrans January 25, 2002 at 5:12 PM (0)
• important! Chin Loong January 23, 2002 at 6:05 AM (0)