Back to Basics

When doing a little refactoring on terracotta server code, I was reminded on why the basics ALWAYS matters.

The server side representation of both ArrayList and LinkedList mapped to a class called ListManagedObjectState. The underlying data structure for this class was a ArrayList. We got around to mapping LinkedList to a LinkedListManagedObjectState where the underlying data structure for that class is a LinkedList.

I wrote a little test and the following where the results:


ArrayList.add for 50000 objects took 424 ms.
LinkedList.add for 50000 objects took 198 ms.
ArrayList.addFirst for 50000 objects took 906 ms.
LinkedList.addFirst for 50000 objects took 109 ms.
ArrayList.addAt for 50000 took objects 105 ms.
LinkedList.addAt for 50000 took objects 132 ms.
ArrayList.clear for 50000 took objects 127 ms.
LinkedList.clear for 50000 took objects 49 ms.
ArrayList.removeFirst for 50000 took objects 847 ms.
LinkedList.removeFirst for 50000 took objects 70 ms.
ArrayList.remove for 50000 took objects 865 ms.
LinkedList.remove for 50000 took objects 68 ms.


If your mutating a lot more then accessing, then LinkedList is the way to go.
Basics do matter!