Need suggestion for variable size array of primitive type.

Question

Hi all,
I am working on a problem in which I need to keep an array of primitive (type int) sorted. Also I insert new elements while keeping it sorted, and at times I merge two similar arrays with unique elements.
I would welcome suggestions on the implementation aspects as to which type/class to use. My primary consideration is performance. Here are my observations:
1. type int
Efficient operation, but arrays are fixed size so it makes clumsy code and overhead when the array is expanded or merged with another.
Methods in class Arrays can be used, incl. binary search and sort.
2. Vector, ArrayList, List, LinkedList
Accept objects only. I can use Integer instead of int, but it will involve overhead, and I'll need to write my own sort and search routines (already done).
For now, I choose option 2 using Vectors. Is there a better choice, or are there other options, given the conditions and consideration enumerated at the beginning?
Appreciate any input or comments.

Answer 1

mathmate wrote:
I have not had the occasion to use them in parallel to recognize the difference. It pays to talk to people!A small benchmark is easily constructed:
import bak.pcj.list.IntArrayList;
import java.util.Random;
import java.util.ArrayList;
public class CollectionTest {
    static void testObjectsList(ArrayList<Integer> list, int n, long seed) {
        long start = System.currentTimeMillis();
        Random rand = new Random(seed);
        for(int i = 0; i < n; i++)
            list.add(new Integer(rand.nextInt()));
        for(int i = 0; i < n/2; i++)
            list.remove(rand.nextInt(list.size()));
        long end = System.currentTimeMillis();
        System.out.println("objectsList -> "+(end-start)+" ms.");
    static void testPrimitiveList(IntArrayList list, int n, long seed) {
        long start = System.currentTimeMillis();
        Random rand = new Random(seed);
        for(int i = 0; i < n; i++)
            list.add(rand.nextInt());
        for(int i = 0; i < n/2; i++)
            list.remove(rand.nextInt(list.size()));
        long end = System.currentTimeMillis();
        System.out.println("primitiveList -> "+(end-start)+" ms.");
    public static void main(String[] args) {
        long seed = System.currentTimeMillis();
        int numTests = 100000;
        testObjectsList(new ArrayList<Integer>(), numTests, seed);
        testPrimitiveList(new IntArrayList(), numTests, seed);
}In the test above, Java's ArrayList is about 5 times faster. But when commenting out the remove(...) methods, the primitive 3rd party IntArrayList is about 4 to 5 times faster.
Give it a spin.
Again: just try to do it with the standard classes: if performance lacks, look at something else.