Stylebooks are nothing new to the writing trades. Each publication has one; they dictate such things as whether Bob Jones is called "Mr. Jones" or simply "Jones" on second reference. Stylebooks give a publication's writers a consistent sound and make it easier for readers to extract the information they want. Though they're not exactly the same as magazine stories, computer programs are written works too. In
Essential Java Style: Patterns for Implementation, Jeff Langr holds forth on a series of Java judgment calls, explaining why he thinks certain approaches are better than others. In his defense of his strategies (patterns, to use object-orientation jargon), Langr takes into account both the human need to read the source code and the design goal of making the program execute speedily and in a resource-efficient way. The approach Langr outlines here should prove useful on large software projects, particularly those that involve multiple team members that need to quickly figure out what the others are doing.
Langr's opinion on the "instanceof" operator is a good example. Generally, he says, "instanceof" is a bad tool to use (in a manner similar to that of a switch statement) for identifying an object's class. It's a resource pig, and multiple tests can be hard to follow in code. It's better, he says, to use polymorphism to endow each of several subclasses with identically named methods, each with a different effect. This is the kind of stuff Java programmers debate all the time, but Essential Java Style makes strong cases for many stock solutions. --David Wall
Topics covered: Patterns for solving programming problems in Java, including those relating to methods, messages, problems of state, data structures, formatting, and execution tweaking.
