Class 43: Some List ADTs

Held: Wednesday, 16 April 2003

Summary: Today we consider the design of various list ADTs.

Related Pages:

• EBoard.
• Documentation for java.util.List.

Notes:

• Are there any questions on the exam?
• Extra credit for attending cool talk on effects of summer research today at 4:15.
• I've started to put together a list of extra credit so that you can check off all of the things you've done. Let me know of any additions.
• I'll be gone this weekend (through Monday's class) and may not have email access. You should still show up to Monday's class.

Overview:

• What is a list?
• A SimpleList ADT.
• An OrderedList ADT.
• An SortedList ADT.
• The java.util perspective.

Types of Lists

• A list is, in essence, a collection of elements that you can iterate.
  • By iterate, I mean that you can visit the elements of the list one by one.
• We tend to think of three related kinds of lists:
  • Simple Lists are the simplest (as their name suggests). They are collections. They are iterable. That's about it. (In particular, the client does not get to control the order in which the elements are iterated.)
  • Ordered Lists give the client control over the order in which the elements are iterated. You can talk about adding something before or after an element of an ordered lists.
  • Sorted Lists are iterated in sorted order (typically from smallest to largest).
• As I've suggested before, one key way to think about abstract data types is to think about their key operations. Let's visit these.

A SimpleList ADT

Left for class discussion.

An OrderedList ADT

Left for class discussion.

A SortedList ADT

Left for class discussion.

Java's java.util.List Interface

• We may spend a few minutes looking at what the folks at Sun came up with.
• You can find this documentation at http://java.sun.com/j2se/1.4.1/docs/api/java/util/Collection.html.