Miscellaneous Classes

For the implementation of the News Cache the following classes have been implemented in addition to those described in chapter 5. These classes are mostly classes used to provide the multiplexing functionality explained in section 4.3 or to provide better access to other resources used by the News Cache.

Multiplexing List

The Multiplexing List (MPList) is necessary for the News Cache's multiplexing functionality. It decides which news server to contact for which newsgroup.

The MPList class is a list of MPListEntries . Each MPListEntry stores which newsgroups should be used from which news server. Table 6.8 shows a sample MPList .

 

News Server Newsgroups Description

news.tuwien.ac.at:nntp * All newsgroups should be provided

news.wu-wien.ac.at:nntp at.wu-wien.* The newsgroups of the ``Wirtschaftsuniversität Wien''

.NoServer alt.binaries.*,soc.* Newsgroups that should be censored

sstream

This class provides a socket stream. It allows to connect to a TCP service. Data written to this stream will be sent to the service. Data sent by the service can be read from this stream. It inherits the methods provided by fstream and provides the following additional methods.

connect(char *name, char *service)

connects to service at host name. The service parameter can either be a valid service name or a port number preceded by the # sign (e.g., #12000).

is_connected()

returns whether sstream is connected to a host. This method has the same semantics as the is_open method.

disconnect()

disconnects from the service.