6 Further Implementation Issues

This section briefly describes the implementation of the distribution library. Only the implementation details necessary to understand how the library should be used, are explained.

The implementation of the BETA distribution library builds on the notion of proxy objects. This means that references to remote objects are really references to local objects representing the remote object, as illustrated in figure 5.

Figure 5: The proxy concept.

Proxies are automatically instantiated by the distribution library when a reference to a remote object enters a shell for the first time. Likewise, unused proxies are automatically garbage collected. In figure 5, the object o1 has a reference to the remote object o2. In practice this means that o1 has a reference to a local proxy p2 representing o2. Method calls to p2 are automatically redirected to o2 by sending the request across the network.