Maximum Size List in Java

Question

It's useful to me to have a data structure in Java that has all the functionality of a List, but has a maximum storage capacity, and drops older data when newer data is added. Conceivably at some point I might want to implement a fixed size Queue which keeps a more general ordering of the data, and drops the old data lowest in that ordering, but that's the for the future.

At the moment I'm implementing it like this:

public class FixedSizeList<T> {

  private final int maxSize;
  private final LinkedList<T> list = new LinkedList<T>();

  public FixedSizeQueue(int maxSize) {
    this.maxSize = maxSize < 0 ? 0 : maxSize;
  }

  public T add(T t) {
    list.add(t);
    return list.size() > maxSize ? list.remove() : null;
  }

  // add remaining methods...

}

Is there either (a) an existing data structure that serves my needs, or (b) a better way of implementing this data structure?

Answer 1

I would use array and 2 indexes for head and tail of the list.Make sure that head is always < tail and you're safe.