<?php
/**
*File name: WorkUnit.php
*Created by: ShowJoy
*Contact: 734578348@qq.com, xubiao522@gmail.com
*Last modified: 2014-5-24
*/

abstract class WorkUnit{
    protected $tasks = array();
    protected $name = NULL;
    
    function __construct($name){
        $this->name = $name;
    }
    
    function getName(){
        return $this->name;
    }
    
    abstract function add(Employee $e);
    abstract function remove(Employee $e);
    abstract function assignTask($task);
    abstract function completeTask($task);
}

class Team extends WorkUnit{
    private $_employees = array();
    
    function add(Employee $e){
        $this->_employees[] = $e;
        echo "<p>{$e->getName()} has been added to team {$this->getName()}.</p>";
    }
    
    function remove(Employee $e){
        $index = array_search($e, $this->_employees);
        unset($this->_employees[$index]);
        echo "<p>{$e->getName()} has been removed from team {$this->getName()}.</p>";
    }
    
    function assignTask($task){
        $this->tasks[] = $task;
        echo "<p>A new task has been assigned to team {$this->getName()}. It should be easy to do with {$this->getCount()} team member(s).</p>";
    }
    
    function completeTask($task){
        $index = array_search($task, $this->tasks);
        unset($this->tasks[$index]);
        echo "<p>The ‘$task‘ task has been completed by team {$this->getName()}.</p>";
    }
    
    function getCount(){
        return count($this->_employees);        
    }
}

class Employee extends WorkUnit{
    function add(Employee $e){
        return false;
    }
    
    function remove(Employee  $e){
        return false;
    }
    
    function assignTask($task){
        $this->tasks[] = $task;
        echo "<p>A new task has been assigned to {$this->getName()}. It will be done by {$this->getName()} alone.</p>";
    }
    
    function completeTask($task){
        $index =  array_search($task, $this->tasks);
        unset($this->tasks[$index]);
        echo "<p>The ‘$task‘ task has been completed by employee {$this->getName()}.</p>";
    }
}
?

<?php
/**
*File name: compsite.php
*Created by: ShowJoy
*Contact: 734578348@qq.com, xubiao522@gmail.com
*Last modified: 2014-5-24
*/

require ‘WorkUnit.php‘;

$team = new Team(‘showjoy‘);
$e1 = new Employee(‘xu‘);
$e2 = new Employee(‘biao‘);
$e3 = new Employee(‘god‘);

$team->add($e1);
$team->add($e2);
$team->add($e3);

$team->assignTask(‘do something by team‘);
$e1->assignTask(‘do it alone‘);

$team->completeTask(‘do something by team‘);

$e1->completeTask(‘do it alone‘);

unset($team,$e1,$e2,$e3); ?>