Steven Schwell

The Observer Design Pattern is among the most useful for object-oriented software design. The JDK itself makes heavy use of a variant of this pattern in the 1.1 AWT event delegation model. The JDK also provides a reusable embodiment of the pattern in the form of the java.util.Observer interface and the java.util.Observable class. If you've done much serious Java programming you've more than likely had occasion to use these classes. The idea of the pattern is to model a one-to-many dependency without tightly coupling the observed object with its many observers. When the observed object changes in some interesting way it can automatically notify all of its observers without knowing them directly. For more on this pattern, see Qusay Mahmoud's article, "Implementing Design P... (more)

An Object Pool Using Remote Method Invocation

Implementation of a fixed size pool of Objects in a distributed application must consider problems caused by the unpredictable nature of remote connections. An implementation is presented here for Java's Remote Method Invocation, which takes advantage of the Distributed Garbage Collector to solve those problems. You're probably familiar with the mechanism of a fixed size pool of Objects, ... (more)