gistfile1.aw

<?php

trait MySingleton
{
  private $_foo = null;
 
  private static $_instance = null;

  private function __construct()
  {
  }

  public static function getInstance() 
  {
    if (!isset(self::$_instance)) {
      $class = __CLASS__;
      self::$_instance = new $class;
    }

    return self::$_instance;
  }

  public function setFoo($foo)
  {
    $this->_foo = $foo;
  }

  public function getfoo()
  {
    if ($this->_foo) {
      return $this->_foo;
    }

    return false;
  }
}

class Foo
{
  use MySingleton;
}

$foo = Foo::getInstance();
$foo->setFoo("foo\n");

echo $foo->getFoo();

$bar = Foo::getInstance();
echo $bar->getFoo();