Using a distributed object system to find and download java-based applications

摘要

A client enabled to load and run Java applets in a distributed object computing system retrieves needed Java classes in a location-independent manner from various class servers in the system. Initially, the client queries a naming service of the distributed object computing system to determine the class server that contains the base class needed. A connection through an object request broker is made from the client to the class server. The client then requests the code for the base class from the class server by using the object request broker. The class server retrieves the code by either reading a file from its own local file set, or if the code is not local, queries the naming service for another class server that has access to the code for the base class. This process of finding a class server and determining if the code is local may be recursive as classes may be moved or renamed. The class server then returns this code to the client by way of the object request broker. The client determines whether the returned code contains any unresolved classes, i.e., classes that are used but not yet defined or loaded. The client requests code for any unresolved class in a manner as above for the base class. The client incorporates Java software to run the applets and ORB binding software to enable the software to make calls to the object request broker. A network class loader enables the client to load and resolve classes over a distributed object system.