Java Distributed Computing

Issues with Collaboration

For the most part, the issues that come up with collaborative systems are similar to those that arise in other concurrent programming tasks. In the context of collaborative systems, some of these issues take on even more importance; and, of course, collaboration raises a few issues of it own. In this section, we’ll look briefly at four of the most important issues: communication needs, identity management, shared state information, and performance.

Communication Needs

A collaborative system has multiple remote agents collaborating dynamically, so it must be flexible in its ability to route transactions. Depending on the application, the underlying communications might need to support point-to-point messages between agents, broadcast messages sent to the entire agent community, or “narrowcast” messages sent to specific groups of participating agents. An interactive chat server that supports chat rooms is a good example of this. Messages are normally broadcast to the entire group, but if an individual is in a single chat room, then her messages should only be sent to the other participants in that room. In some cases, you may need to support private, one-on-one messaging between agents or users in the system (e.g., for private discussions).

In addition to simple message-like communications, there may be a need for agents to have a richer interface to other agents. Agents may need to pass object data to each other, and remote agents may need to interact directly ...