Refactoring To Command Pattern

//usage of command pattern to refactoring big or overloaded methods
//Gigantic classes with hard to change methods
class Wrong_Customer {
    var  $_age;
    var $_bill;
    var $_man;
    function __construct($age, $bill, $man) {
        $this->_age=$age;
        $this->_bill=$bill;
        $this->_man= $man;
    }
    //addind discount will require modyfy other classes
    //new calculation devices requre to chenge methods
    function returnFinalBill() {
        $discountPercent=0;
        if($this->_age >60) { $discountPercent +=0.10;}
        if(!$this->_man) { $discountPercent +=0.20;}
        $bill = $this->_bill*(1-$discountPercent);   //100%=1
        return ("Wrong Customer Bill Amount: $".$bill."

");
    }
}

interface BillPlayer {
    //based on sex how to calculate bill
    public function calculateBill($amountDue);
}
interface Command {
    //methods that change
    function executeCalculateBill($amountDue);
}

class WomanOver60 implements BillPlayer {
     public function calculateBill($amountDue) {
         return "Bill Amount for Woman over 60: $".($amountDue*(1-0.30))."

";
     }
}
class ManOver60 implements BillPLayer {
     public function calculateBill($amountDue) {
         return "Bill Amount for Man over 60: $".($amountDue*(1-0.10))."

";
     }
}
class ManUnder60 implements BillPLayer {
    public function calculateBill($amountDue) {
        return "Bill Amount for Man under 60: $".($amountDue)."

"; //no discount
    }
}

class Waiter implements Command {    //Comander
    var $_billPayer;
    function __construct(BillPlayer $billPayer) {
        $this->_billPayer=$billPayer;
    }
    function executeCalculateBill($amountDue) {
        return $this->_billPayer->calculateBill($amountDue);
    }
}

class CashRegister {    //invoker from command pattern, execute diferent methods based onobject type passed
    //return final bill
    //_Waiter diferent weiters, !adds flexibility!
    //stores Command's
    var $_command;

    function __construct(Command $command) {
        $this->_command=$command;    //all things that implements command //like waiters
    }
    function returnFinalBill($amountDue) {
        return $this->_command->executeCalculateBill($amountDue);
    }
}

// more flexebility - only one thing to change for adding bill Payers
class CustomerTypePicker {  //if u want NEW bill payer tpe goes here!!!
    static function getManOver60(){
        return new ManOver60();
    }
    static function getManUnder60(){
        return new ManUnder60();
    }
    static function getWomanOver60(){
        return new WomanOver60();
    }
}
//adding customer group for easier to menage diferent customers
class CustomerGroup {
    private $_customers=array();
    function __construct($customers=array()) {
        $this->_customers = $customers;
    }
    function getCustomer($index) {
        return $this->_customers[$index];
    }
    function addCustomer(BillPlayer $customer) {
        return $this->_customers[]=$customer;
    }//TODO deleteCustomer

}

class Main {
    function __construct() {
        $wC = new Wrong_Customer(70, 100, false); //woman Over 60
        echo $wC->returnFinalBill();
    }
    function testCommandOnWomenOver60() {
        $picker = new CustomerTypePicker();
        $sally = $picker::getWomanOver60();
        $waiter = new Waiter($sally);    //sallysWaiter
        $bill = new CashRegister($waiter);
        echo $bill->returnFinalBill(100);
    }
    function testCommandOnManOver60() {            //NOW better groups customers to array
        $picker = new CustomerTypePicker();
        $bob = $picker::getManOver60();
        $waiter = new Waiter($bob);    //sallysWaiter
        $bill = new CashRegister($waiter);
        echo $bill->returnFinalBill(100);
    }
    function testCustomerGroup() {
        $picker = new CustomerTypePicker();
        $customerGroup = new CustomerGroup();
        $sally = $picker::getWomanOver60();
        $customerGroup->addCustomer($sally);
        echo $customerGroup->getCustomer(0)->calculateBill(100);
    }
}

$run = new Main();
$run->testCommandOnWomenOver60();
$run->testCommandOnManOver60();
$run->testCustomerGroup();

Java implementation here: http://www.newthinktank.com/2013/02/code-refactoring-13/