Implementation Patterns

Chapter 9. Collections

I must say that I didn’t expect this chapter to amount to much. When I started writing it, I thought I would end up with an API document—types and operations. The basic idea is simple: a collection distinguishes between objects in the collection and those not in the collection. What more was there to say?

What I discovered is that collections are a far richer topic than I ever suspected, both in their structure and the possibilities they offer for communicating intent. The concept of collections blends several different metaphors. The metaphor you emphasize changes how you use collections. Each of the collection interfaces communicates a different variation on the theme of a sack of objects. Each of the implementations ...