$obj->setHoge('a')->setPiyo('b')->setFoo('c')->setBar('d')
$obj->setAttributes('Hoge','a')->setAttributes('Piyo','b')->setAttributes('Foo','c')->setAttributes('Bar','d')
$obj->setAttributes(array('Hoge','Piyo','Foo','Bar'), array('a','b','c','d'))
$obj->setAttributes(array('Hoge'=>'a','Piyo'=>'b','Foo'=>'c','Bar'=>'d'))

どれがお好み?