What is better performance HashMap or a TreeSet

[rastas biggs]

What is more effeciant A HashMap or a TreeSet in terms of performace.

A HasMap is easier for me to implement by calling the key to get the value,
but would performace be a factor.

A treeSet will return the data in the order I added it from the record set.
But is more difficult to manipulate.

My problem is the output to a file has to be exact like so..

ID|Name|Address|zipcode etc..

Any suggestions?

RB

[Layne Lund]

I honestly don't think it is fair to compare HashMap with TreeSet because they serve two different purposes. A Map stores a value based on a key, whereas a Set stores unique values without a key. It might be more productive to compare HashMap with TreeMap or HashSet with TreeSet instead. Again, there is more to compare than just efficiency. TreeMap and TreeSet keep the elements in a sorted order (defined by the Comparable or Comparator interfaces), whereas HashMap and HashSet are unsorted. Of course, the sorting comes with an efficiency cost, so you have to take that into account. For more details, you should check out the Java API docs. They explain the efficiency considerations for these classes quite clearly (at least if you understand Big-Oh notation).

Layne

[marc weber]

This might give you some implementation tips...

http://java.sun.com/docs/books/tutorial/collections/implementations/general.html

For more detailed information, see the "Choosing an Implementation" section in the "Collections" chapter of Bruce Eckel's Thinking in Java (about 3/4 of the way through the chapter)...

http://www.faqs.org/docs/think_java/TIJ313.htm
[ November 04, 2004: Message edited by: marc weber ]