This is the base interface for derived interfaces
that represent various types of messages. This package is
designed to work with Message objects that
may contain different elements depending on the underlying
messaging protocol. This is different from Datagrams that
are assumed always to be just blocks of binary data.
An adapter specification for a given messaging protocol
may define further interfaces derived from the Message
interfaces included in this generic specification.
The wireless messaging protocols that are accessed
via this API are typically of store-and-forward nature,
unlike network layer datagrams. Thus, the messages will
usually reach the recipient, even if the recipient is not
connected at the time of sending the message. This may
happen significantly later if the recipient is
disconnected for a long time. Sending, and possibly also
receiving, these wireless messages typically involves
a financial cost to the end user that cannot be neglected. Therefore,
applications should not send many messages unnecessarily.
This interface contains the functionality common
to all messages. Concrete object instances representing
a message will typically implement other (sub)interfaces
providing access to the content and other information in
the message which is dependent on the type of the message.
Object instances implementing this interface are just
containers for the data that is passed in. The setAddress()
method just sets the value of the address in the
data container without any checking whether the value
is valid in any way.
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