php observer

observer.sample.php

<?php
abstract class Observer
{
    abstract public function update( $generator );
}

class AddressObserver extends Observer
{
    public function update( $generator ){
        print $generator->get_data() . "\n";
    }
}

class GpsObserver extends Observer
{
    public function update( $generator ){
        $address = $generator->get_data();
        print "lat:35.690921 lon:139.700258 \n";
    }
}

abstract class Data
{
    private $_observers = array();

    public function add_observer( $observer ){
        $this->_observers[] = $observer;
    }

    public function notify_observer(){
        foreach( $this->_observers as $ovserver ){
            $ovserver->update( $this );
        }
    }

    abstract public function get_data();
    abstract public function execute();
}

class AddressData extends Data
{
    private $_address;

    public function get_data(){
        return $this->_address;
    }

    public function execute(){
        $this->_address = "Shinjuku";
        parent::notify_observer();
    }
}

$number_generator = new AddressData();
$number_generator->add_observer( new AddressObserver() );
$number_generator->add_observer( new GpsObserver() );
$number_generator->execute();