The generic collection library

You’ve seen in this chapter that the standard Java library has some fairly useful collections, but far from a complete set. In addition, algorithms like sorting are not supported at all. One of the strengths of C++ is its libraries, in particular the Standard Template Library (STL) that provides a fairly full set of collections as well as many algorithms like sorting and searching that work with those collections. Based on this model, the ObjectSpace company was inspired to create the Generic Collection Library for Java (formerly called the Java Generic Library , but the abbreviation JGL is still used – the old name infringed on Sun’s copyright), which follows the design of the STL as much as possible (given the differences between the two languages). The JGL seems to fulfill many, if not all, of the needs for a collection library, or as far as one could go in this direction without C++’s template mechanism. The JGL includes linked lists, sets, queues, maps, stacks, sequences, and iterators that are far more functional than Enumeration, as well as a full set of algorithms such as searching and sorting. ObjectSpace also made, in some cases, more intelligent design decisions than the Sun library designers. For example, the methods in the JGL collections are not final so it’s easy to inherit and override those methods.

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