Class 42: Vectors

Held: Tuesday, April 19, 2005

Summary: Today we consider the standard Java class java.util.Vector. Vectors are the kitchen sinks of data structures: Although Vectors are primarily designed as expandable arrays, they also provide a wide variety of other methods.

Related Pages:

• EBoard.
• Lab on Vectors in Java.
• API for java.util.Vector.

Notes:

• We may have a few visitors today (prospies, junior faculty, etc.).
• I'd like you to write up the Hash table lab and turn it in by next Monday.

Overview:

• Vector philosophy.
• Vector methods.
• Lab.

The Core Ideas of java.util.Vector

• java.util.Vector is one of the most useful (and generally used) utility classes in Java.
• From one perspective, Vectors are just expandable arrays.
  • You should know how to implement such things.
• Vectors make an interesting decision: You must explicitly set the size or add things at the end.
  • You can't just set something beyond the current end of the vector.
• Vectors also implement a host of other methods. (I call them the kitchen sink of data structures as a play on the phrase everything but the kitchen sink.)
  • Most involve things you'd like to do when using arrays to implement other data structures (inserting or removing something and having everything else shift, etc.)