Encapsulated classifier is structured classifier extended with the ability to own ports.
UML 2.4 specification provides no definition of encapsulation. It also uses term completely encapsulated without appropriate explanation. It states that classifier could be isolated from its environment (encapsulated ?) by using ports. Each port could specify a distinct interaction point between classifier and its environment.
Library Services is classifier encapsulated through Search Port
Note, that because encapsulated classifier extends structured classifier, it may also have some internal structure. UML allows several alternative notations for connecting simple ports on the parts and roles.
The only mandatory notation for connecting ports in an internal structure is when the connector is joined directly to the ports. Optional lollipop and socket could show provided and required interfaces of the connected ports.
Simple ports joined directly by connector, mandatory UML notation.
Customers component part provides Account interface to Orders part.