"Yes," Lily called through the door. She didn't bother saying that he couldn't come in. That would be pretty obvious once he tried. Sure enough, she heard him try to open the door just moments later. Apparently he hadn't seen her announcement that her door was heavily charmed. Or he just didn't care. She wouldn't be surprised if it was the latter. Stubborn boys.
"You're not getting in," she added to let him know she had heard him try the doorknob. At least, she hoped he wasn't getting in. To figure out all of the charms she used would take someone else skilled in the subject, and she couldn't really say she knew what his talents were. She may have spent years in love with him, but she didn't stalk him.