This package contains all the
headers interfaces supported by this specification. SIP header fields are
similar to HTTP header fields in both syntax and semantics. This specification
models each SIP header as a specific interface as opposed to have a single
generic interface to handle all header information. It is deemed more explicit
for protocol support to define protocol characteristics as opposed to generic
interfaces. This specification supports all the headers defined in RFC 3261
and other headers introduced by supporting the following additional RFC's:
- RFC3262 - RAckHeader and RSeqHeaders for the reliable delivery of provisional
responses.
- RFC3265 - AllowEventsHeader, EventHeader and SubscriptionStateHeader
to support the event notification framework.
- RFC3326 - ReasonHeader to support information on why the request was
issued.
This specification also provides a mechanism to support other extension
Headers. If a SIP stack vendor supports such extension headers these must
extend the ExtensionHeader interface, which contains header name and header
value attributes.
Additionally this package contains a HeaderFactory class that defines methods for creating new headers. The HeaderFactory is a singleton object, which can be obtained from the {@link javax.sip.SipFactory}.