Java Distributed Computing

Chapter 3. Distributing Objects

Distributed objects are a potentially powerful tool that has only become broadly available for developers at large in the past few years. The power of distributing objects is not in the fact that a bunch of objects are scattered across the network. The power lies in that any agent in your system can directly interact with an object that “lives” on a remote host. Distributed objects, if they’re done right, really give you a tool for opening up your distributed system’s resources across the board. And with a good distributed object scheme you can do this as precisely or as broadly as you’d like.

The first three sections of this chapter go over the motivations for distributing objects, what makes distributed object systems so useful, and what makes up a “good” distributed object system. Readers who are already familiar with basic distributed object issues can skip these sections and go on to the following sections, where we discuss two major distributed object protocols that are available in the Java environment: CORBA and RMI.

Although this chapter will cover the use of both RMI and CORBA for distributing objects, the rest of the book primarily uses examples that are based on RMI, where distributed objects are needed. We chose to do this because RMI is a simpler API and lets us write relatively simple examples that still demonstrate useful concepts, without getting bogged down in CORBA API specifics. Some of the examples, if converted to be used in production ...