public void testCompareAndSet() {
    double prev = Math.E;
    double unused = Math.E + Math.PI;
    AtomicDouble at = new AtomicDouble(prev);
    for (double x : VALUES) {
      assertBitEquals(prev, at.get());
      assertFalse(at.compareAndSet(unused, x));
      assertBitEquals(prev, at.get());
      assertTrue(at.compareAndSet(prev, x));
      assertBitEquals(x, at.get());
      prev = x;
    }
  }

    for (int i : new int[] {0, SIZE - 1}) {
      double prev = 0.0;
      double unused = Math.E + Math.PI;
      for (double x : VALUES) {
        assertBitEquals(prev, aa.get(i));
        assertFalse(aa.compareAndSet(i, unused, x));
        assertBitEquals(prev, aa.get(i));
        assertTrue(aa.compareAndSet(i, prev, x));
        assertBitEquals(x, aa.get(i));
        prev = x;
      }
    }
  }

    checkNotNull(comparator);
    Iterator<? extends T> it = iterable.iterator();
    if (it.hasNext()) {
      T prev = it.next();
      while (it.hasNext()) {
        T next = it.next();
        if (comparator.compare(prev, next) > 0) {
          return false;
        }
        prev = next;
      }
    }
    return true;
  }

  /**

    SettableFuture<String> orig = SettableFuture.create();
    SettableFuture<String> prev = orig;
    for (int i = 0; i < 100000; i++) {
      SettableFuture<String> curr = SettableFuture.create();
      prev.setFuture(curr);
      prev = curr;
    }
    // prev represents the 'innermost' future
    prev.set("done");
    assertTrue(orig.isDone());
  }

    SettableFuture<String> orig = SettableFuture.create();
    SettableFuture<String> prev = orig;
    for (int i = 0; i < 100000; i++) {
      SettableFuture<String> curr = SettableFuture.create();
      prev.setFuture(curr);
      prev = curr;
    }
    // prev represents the 'innermost' future
    prev.set("done");
    assertTrue(orig.isDone());
  }

   * prev}. {@code ENDPOINT} represents either the first or last entry in the entire map (as
   * appropriate).
   */
  private void setSucceeds(int prev, int next) {
    if (prev == ENDPOINT) {
      firstInInsertionOrder = next;
    } else {
      nextInInsertionOrder[prev] = next;
    }
    if (next == ENDPOINT) {
      lastInInsertionOrder = prev;
    } else {

      int smearedHash = smearedHash(o);
      int bucket = smearedHash & mask();
      ValueEntry<K, V> prev = null;
      for (ValueEntry<K, V> entry = hashTable[bucket];
          entry != null;
          prev = entry, entry = entry.nextInValueBucket) {
        if (entry.matchesValue(o, smearedHash)) {
          if (prev == null) {
            // first entry in the bucket
            hashTable[bucket] = entry.nextInValueBucket;

        final StringBuilder buf = new StringBuilder(searchWord.length());
        char prev = 0;
        for (final char c : searchWord.toCharArray()) {
            if (!Character.isWhitespace(c)) {
                buf.append(c);
            } else if (!Character.isWhitespace(prev)) {
                buf.append(' ');
            }
            prev = c;
        }
        final String[] words = buf.toString().trim().split(" ");

      int smearedHash = smearedHash(o);
      int bucket = smearedHash & mask();
      ValueEntry<K, V> prev = null;
      for (ValueEntry<K, V> entry = hashTable[bucket];
          entry != null;
          prev = entry, entry = entry.nextInValueBucket) {
        if (entry.matchesValue(o, smearedHash)) {
          if (prev == null) {
            // first entry in the bucket
            hashTable[bucket] = entry.nextInValueBucket;

        // not all.  See the test cases for examples on how this can happen.
        try {
          ((Thread) currentRunner).interrupt();
        } finally {
          Runnable prev = getAndSet(DONE);
          if (prev == PARKED) {
            LockSupport.unpark((Thread) currentRunner);
          }
        }
      }
    }
  }

  /**