Interface DocAttribute is a tagging interface which a printing attribute class implements to indicate the attribute denotes a setting for a doc. ("Doc" is a short, easy-to-pronounce term that means "a piece of print data.") The client may include a DocAttribute in a Doc's attribute set to specify a characteristic of that doc. If an attribute implements PrintRequestAttribute as well as DocAttribute, the client may include the attribute in a attribute set which specifies a print job to specify a characteristic for all the docs in that job.