This pattern is all about interfaces. It is, therefore,
hard to summarize the interface issues in two paragraphs. However, the key
point to understand is that the adapter implements the target interface and so
exposes methods which are useful to the client. This is an interacting
interface which the clients will access since they should be able to switch seamlessly
between interacting with a class, which naturally exposes the target interface
and an adaptee which exposes the target interface through the adapter.