Php design mode Factory (Factory mode)

Defines an interface for creating objects, so that the subclass determines which class to instantiate and delays the instantiation of a class to its subclass. Copy codeThe code is as follows:
/**
* Factory method mode
*
* Defines an interface for creating objects so that the subclass decides which class to instantiate and delays the instantiation of a class to its subclass.
*/

/*
Class DBFactory
{
Public static function create ($ type)
{
Swtich ($ type)
{
Case "Mysql ":
Return new MysqlDB (); break;
Case "Postgre ":
Return new Analytic DB (); break;
Case "Mssql ":
Return new MssqlDB (); break;
}
}
}
*/
Class DBFactory
{
Public static function create ($ type)
{
$ Class = $ type. "DB ";
Return new $ class;
}
}

Interface DB
{
Public function connect ();
Public function exec ();
}

Class MysqlDB implements DB
{
Public function _ construct (){
Echo "mysql db
";
}

Public function connect (){
}

Public function exec (){
}
}

Class Analytic DB implements DB
{
Public function _ construct (){
Echo "Postgre db
";
}

Public function connect (){
}

Public function exec (){
}
}

Class MssqlDB implements DB
{
Public function _ construct (){
Echo "mssql db
";
}

Public function connect (){
}
Public function exec (){
}
}

$ OMysql = DBFactory: create ("Mysql ");
$ OPostgre = DBFactory: create ("Postgre ");
$ OMssql = DBFactory: create ("Mssql ");