Map<String, DfsState> stateMap,
            LinkedList<String> cycle) {
        if (children != null) {
            for (String v : children) {
                DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
                if (state == null) {
                    cycle.addLast(v);
                    List<String> ret = visitCycle(graph, graph.get(v), stateMap, cycle);
                    if (ret != null) {

    @Override
    public void replaceAll(final BiFunction<? super K, ? super V, ? extends V> function) {
        parent.replaceAll(function);
    }

    @Override
    public V putIfAbsent(final K key, final V value) {
        return parent.putIfAbsent(key, value);
    }

    @Override
    public boolean remove(final Object key, final Object value) {
        if (parent.remove(key, value)) {
            return true;

    assertNull(map.put(one, two));
    assertSame(two, map.get(one));
    map.putAll(ImmutableMap.of(two, three));
    assertSame(three, map.get(two));
    assertSame(two, map.putIfAbsent(one, three));
    assertSame(two, map.get(one));
    assertNull(map.putIfAbsent(three, one));
    assertSame(one, map.get(three));
    assertSame(two, map.replace(one, three));
    assertSame(three, map.get(one));

   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values
   * into the cache. Newly loaded values are added to the cache using {@code
   * Cache.asMap().putIfAbsent} after loading has completed; if another value was associated with
   * {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *

   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values
   * into the cache. Newly loaded values are added to the cache using {@code
   * Cache.asMap().putIfAbsent} after loading has completed; if another value was associated with
   * {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *

      }
      checkArgument(occurrences > 0, "Invalid occurrences: %s", occurrences);

      while (true) {
        int current = count(element);
        if (current == 0) {
          if (countMap.putIfAbsent(element, occurrences) == null) {
            return 0;
          }
        } else {
          checkArgument(
              occurrences <= Integer.MAX_VALUE - current,

    assertEquals(Integer.valueOf(50), asMap.get(10));
    assertEquals(null, cache.getIfPresent(2));
    assertEquals(null, asMap.get(2));

    asMap.putIfAbsent(2, 20);
    asMap.putIfAbsent(10, 20);

    assertEquals(Integer.valueOf(20), cache.getIfPresent(2));
    assertEquals(Integer.valueOf(20), asMap.get(2));
    assertEquals(Integer.valueOf(50), cache.getIfPresent(10));

      }
    }
  }

  public void fetch(HttpUrl url) throws IOException {
    // Skip hosts that we've visited many times.
    AtomicInteger hostnameCount = new AtomicInteger();
    AtomicInteger previous = hostnames.putIfAbsent(url.host(), hostnameCount);
    if (previous != null) hostnameCount = previous;
    if (hostnameCount.incrementAndGet() > 100) return;

    Request request = new Request.Builder()
        .url(url)
        .build();

            E result = (E) canonical;
            return result;
          }
        }

        // didn't see it, trying to put it instead...
        Dummy sneaky = map.putIfAbsent(sample, Dummy.VALUE);
        if (sneaky == null) {
          return sample;
        } else {
          /* Someone beat us to it! Trying again...
           *

        destroyProcess(sessionId);
        JobProcess jobProcess;
        try {
            jobProcess = new JobProcess(pb.start(), bufferSize, outputCallback);
            destroyProcess(sessionId, runningProcessMap.putIfAbsent(sessionId, jobProcess));
            return jobProcess;
        } catch (final IOException e) {
            throw new JobProcessingException("Crawler Process terminated.", e);
        }
    }