gistfile1.php

<?php
class DummyClass
{
	public $msg;
}

$obj = new DummyClass();
$obj->msg = "Hello World";
echo $obj->msg.PHP_EOL;

class DummyClass2
{
	private $_msg;

	public function __get($key)
	{
		if ($key == "msg")
			return str_replace(" ", "", $this->_msg);
	}

	public function __set($key, $val)
	{
		if ($key == "msg")
			return $this->_msg = $val;
	}	
}


$obj = new DummyClass2();
$obj->msg = "Hello World";
echo $obj->msg.PHP_EOL;