}

  public void testOnlyOneOpen() throws Exception {
    final ByteSource source = newByteSource(0, 50);
    final int[] counter = new int[1];
    ByteSource checker =
        new ByteSource() {
          @Override
          public InputStream openStream() throws IOException {
            if (counter[0]++ != 0) {
              throw new IllegalStateException("More than one source open");
            }

    ImmutableMap<C, V> row = rowEntry.getValue();
    int columnIndex = cellColumnInRowIndices[index];
    Entry<C, V> colEntry = row.entrySet().asList().get(columnIndex);
    return cellOf(rowEntry.getKey(), colEntry.getKey(), colEntry.getValue());
  }

  @Override
  V getValue(int index) {
    int rowIndex = cellRowIndices[index];

        int counter = 0
        source.filter { File f -> f.name.endsWith(".java") || f.name.endsWith(".groovy") }.each { File f ->
            parse(f, repository)
            counter++
        }

        //updating/modifying the metadata and making sure every type reference across the metadata is fully qualified

    String testString = "abcdefgh";
    final CharSource source = newCharSource(testString);
    final int[] counter = new int[1];
    CharSource reader =
        new CharSource() {
          @Override
          public Reader openStream() throws IOException {
            if (counter[0]++ != 0) {
              throw new IllegalStateException("More than one source open");
            }

    String testString = "abcdefgh";
    final CharSource source = newCharSource(testString);
    final int[] counter = new int[1];
    CharSource reader =
        new CharSource() {
          @Override
          public Reader openStream() throws IOException {
            if (counter[0]++ != 0) {
              throw new IllegalStateException("More than one source open");
            }

  }

  public void testOnlyOneOpen() throws Exception {
    final ByteSource source = newByteSource(0, 50);
    final int[] counter = new int[1];
    ByteSource checker =
        new ByteSource() {
          @Override
          public InputStream openStream() throws IOException {
            if (counter[0]++ != 0) {
              throw new IllegalStateException("More than one source open");
            }

    teststring = newTestString(new Random(1), bitSet, percentMatching);
  }

  @Benchmark
  public int countIn(int reps) {
    int result = 0;
    CharMatcher matcher = this.matcher;
    String teststring = this.teststring;
    for (int i = 0; i < reps; i++) {
      result += matcher.countIn(teststring);
    }
    return result;
  }

  @Benchmark
  public int collapseFrom(int reps) {
    int result = 0;

    teststring = newTestString(new Random(1), bitSet, percentMatching);
  }

  @Benchmark
  public int countIn(int reps) {
    int result = 0;
    CharMatcher matcher = this.matcher;
    String teststring = this.teststring;
    for (int i = 0; i < reps; i++) {
      result += matcher.countIn(teststring);
    }
    return result;
  }

  @Benchmark
  public int collapseFrom(int reps) {
    int result = 0;

While waiting and talking to your crush, from time to time, you check the number displayed on the counter to see if it's your turn already.

Then at some point, it finally is your turn. You go to the counter, get your burgers and come back to the table.

<img src="/img/async/concurrent-burgers/concurrent-burgers-06.png" class="illustration">

    for (int i = 0; i < 1000; i++) {
      final AtomicInteger counter = new AtomicInteger();
      final TrustedListenableFutureTask<Integer> task =
          TrustedListenableFutureTask.create(
              new Callable<Integer>() {
                @Override
                public Integer call() {
                  return counter.incrementAndGet();
                }
              });