package org.openjdk;

import org.openjdk.jmh.annotations.*; 
import java.util.*;

/*
Benchmark                           Mode  Cnt   Score    Error   Units
ListBench.arrayAddToEnd            thrpt    4  53.994 ±  0.093  ops/us
ListBench.arrayAddToEndRemoveLast  thrpt    4  61.146 ±  1.153  ops/us
ListBench.linkedAddToEnd           thrpt    4  27.041 ± 24.087  ops/us
 */
@State(Scope.Benchmark)
public class ListBench {
  List<String> base = List.of("foo", "bar", "baz", "bur", "fur", "dur", "lur", "kur");
  LinkedList<String> linked = new LinkedList<>(base);
  ArrayList<String>  array  = new ArrayList<>(base);

  @Benchmark
  public void linkedAddToEnd() {
    linked.add(linked.removeLast());    
  }

  @Benchmark
  public void arrayAddToEnd() {
    array.add(array.remove(array.size() - 1));
  }

  /**
   * Use a local implementation of ArrayList.removeLast():
   *

    public E removeLast() {
        if (size == 0) {
            throw new NoSuchElementException();
        }
        int newSize = size - 1;
        int modCount++;

        final Object[] es = elementData;
        @SuppressWarnings("unchecked") E oldValue = (E) es[newSize];
        es[newSize] = null;
        size = newSize;
        return oldValue;
    }

   */
  @Benchmark
  public void arrayAddToEndRemoveLast() {
    array.add(array.removeLast());
  }

}