Microbenchmarks of four ways to tokenize a Java string

JavaStringSplits.java

package mechsympathy;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;
import java.util.concurrent.TimeUnit;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;

import com.google.common.base.Splitter;


@OutputTimeUnit(TimeUnit.MILLISECONDS)
@Warmup(iterations = 4, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(2)
public class JavaStringSplits {

  @State(Scope.Benchmark)
  public static class StringState {
    String[] lines = new String[]{
        "0000 12 34 5 666 77 88888 99",
        "aa bb cc dd ee ff gg hh ii jj kk ll mm nn oo pp qq rr ss tt uu vv ww xx yy zz",
        "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod"
        };
  }
  
  @Benchmark
  public static void javaSplit(StringState ss, Blackhole bh) {
    for (String ln: ss.lines) {
      String[] toks = ln.split(" ");
      bh.consume(toks);
    }
  }
    
  @Benchmark
  public static void indexOf(StringState ss, Blackhole bh) {
    for (String ln: ss.lines) {
      List<String> ls = new ArrayList<String>();
      int pos = 0;
      int idx = 0;
      while (true) {
        idx = ln.indexOf(' ', pos);
        if (idx < 0) {
          ls.add(ln.substring(pos, ln.length()));
          break;
        }
        ls.add(ln.substring(pos, idx));
        pos = idx + 1;
      }
      bh.consume(ls);
    }
  }
  
  @Benchmark
  public static void stringTokenizer(StringState ss, Blackhole bh) {
    for (String ln: ss.lines) {
      List<String> ls = new ArrayList<String>();
      StringTokenizer st = new StringTokenizer(ln, " ");
      while (st.hasMoreTokens()) {
        ls.add(st.nextToken());
      }
      bh.consume(ls);
    }
  }
  
  @Benchmark
  public static void guavaSplit(StringState ss, Blackhole bh) {
    for (String ln: ss.lines) {
      List<String> ls = new ArrayList<String>();
      Splitter split = Splitter.on(" ");
      Iterator<String> it = split.split(ln).iterator();
      while (it.hasNext()) {
        ls.add(it.next());
      }
      bh.consume(ls);
    }
  }
}