InterSystems Corp. offers Caché, an object database that is an obvious partner for an OO-language like Java. Jon Elsom, a freelance consultant working with Hang 10 Systems in the UK, shares his experience with Caché. While the product is a bit immature on the Java side, InterSystems has improvements planned for the next version that should help Caché mature rapidly.
The <FONT FACE="Courier">ITERATOR</FONT> pattern represents what many OO developers think of as <I>the</I> design for iteration in an object system, but there is more to iteration abstraction than just <FONT FACE="Courier">ITERATOR</FONT>. Kevlin looks at three iteration patterns—<FONT FACE="Courier">ITERATOR</FONT>, <FONT FACE="Courier">ENUMERATION METHOD</FONT>, and <FONT FACE="Courier">BATCH METHOD</FONT>—whose solutions differ in their response to threading, distribution, exceptions, and parameterization.