[PHP]抽象クラス ref: http://qiita.com/tarunama/items/165b0b46c83d92fa0aad

abstract.php

<?php

abstract class Working
{
    abstract protected function where();
    abstract protected function why();
    abstract protected function how();

    public function work()
    {
        echo $this->where($where);
        echo $this->why($reason);
        echo $this->how($how);
    }
}

class Person extends Working
{
    protected function where()
    {
        return '横浜で';
    }

    protected function why()
    {
        return 'お金欲しいから';
    }

    protected function how()
    {
        return '営業する';
    }
}

$bob = new Person();
$bob->work(); // 横浜でお金欲しいから営業する