advertisements in passing a number of times in this chapter; we even
created advertisements for pipes and groups using the
Advertisements are one of the basic building blocks of JXTA: they
help peers discover any kind of service, including peergroups, other
peers, and pipes. In fact, at a basic level, the JXTA infrastructure
is simply about sending advertisements for various resources around
to interested parties. A JXTA application simply searches for
advertisements it is interested in and responds to requests for
advertisements that it has published. The basic protocols
we’ve mentioned all use advertisements as the
mechanism by which they send data. Advertisements provide a
platform-independent representation of platform objects that can be
exchanged between different platform implementations (Java, C, etc.).
Advertisements are structured XML documents. The JXTA infrastructure defines six such documents:
Developers may subclass these advertisements when they create their own services. For example, a content advertisement could announce that a peer has a particular item (such as a PDF file of this chapter). A JXTA application may create a subclass of the content advertisement to refer only to PDF files of this book. Peers who are interested in generic content can look for standard content ...