O'Reilly logo

JXTA in a Nutshell by Li Gong, Bernard Traversat, Scott Oaks

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Peer Information Protocol

Once a peer is located, its capabilities and status may be queried. The PIP provides a generic framework for obtaining peer status and monitoring information. Peers are not required to respond to PIP requests. A reliable transport is optional.

Multiple peer information messages may be sent. Zero, one, or multiple responses may be received in response to a peer information query. The PIP is layered on the PRP. A QueryID field is used for matching PIP queries to the PIP responses.

Obtaining PIP Responses

The PIP query message provides a request field that may be used to encode a specific request. The PIP does not dictate the format of the request field. Higher-level services could utilize the request field for adding expanded capabilities.

The PIP is composed of a query message, which is sent to query a peer for its current state and other relevant information (see Example 17-6). A query without a defined request field returns a default set of information about a peer (i.e., uptime, message count, etc.).

Example 17-6. Query message schema

<xs:element name="PeerInfoQueryMessage" 
            type="jxta:PeerInfoQueryMessage"/>

<xs:complexType name="PeerInfoQueryMessage">     
   <xs:element name="sourcePid" type="xs:anyURI"/>     
   <xs:element name="targetPid" type="xs:anyURI"/>     
   <xs:element name="request" type="xs:anyType" minOccurs="0"/> </xs:complexType>

The elements in Example 17-6 are:

sourcePid

The source peer ID of the requesting peer

targetPid

The destination peer ID ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required