if (record != null) {
        list.add(record);
      }
    }
  }

  @Override
  public void flush() {}

  @Override
  public void close() {}

  public void clear() {
    synchronized (lock) {
      list.clear();
    }
  }

  /** Returns a snapshot of the logged records. */
  /*
   * TODO(cpovirk): consider higher-level APIs here (say, assertNoRecordsLogged(),

                try {
                    final int sessionIdListSize = finishedSessionIdList.size();
                    intervalControlHelper.setCrawlerRunning(true);

                    docList.clear();
                    accessResultList.clear();

                    updateTime = systemHelper.getCurrentTimeAsLong() - updateTime;

                    final long interval = updateInterval - updateTime;

   * clear()} clears all table mappings.
   */
  @WeakOuter
  private abstract class TableSet<T> extends ImprovedAbstractSet<T> {
    @Override
    public boolean isEmpty() {
      return backingMap.isEmpty();
    }

    @Override
    public void clear() {
      backingMap.clear();
    }
  }

  /**
   * {@inheritDoc}
   *

    assertEquals(1, segment.count);
    assertSame(newValue, segment.get(key, hash));

    // cleared
    segment.setWeakValueReferenceForTesting(entry, oldValueRef);
    oldValueRef.clear();
    assertFalse(segment.replace(key, hash, oldValue, newValue));
    assertEquals(0, segment.count);
    assertNull(segment.get(key, hash));
  }

  public void testSegmentReplace() {

    assertEquals(1, segment.count);
    assertSame(newValue, segment.get(key, hash));

    // cleared
    segment.setWeakValueReferenceForTesting(entry, oldValueRef);
    oldValueRef.clear();
    assertFalse(segment.replace(key, hash, oldValue, newValue));
    assertEquals(0, segment.count);
    assertNull(segment.get(key, hash));
  }

  public void testSegmentReplace() {

    }
  }


  public void testKeySet_clear() {
    for (LoadingCache<Object, Object> cache : caches()) {
      warmUp(cache, 0, 100);

      Set<Object> keys = cache.asMap().keySet();
      keys.clear();
      checkEmpty(keys);
      checkEmpty(cache);
    }
  }

  public void testKeySet_empty_remove() {
    for (LoadingCache<Object, Object> cache : caches()) {

      assertTrue(Thread.holdsLock(mutex));
      return delegate.retainAll(collection);
    }

    @Override
    public void clear() {
      assertTrue(Thread.holdsLock(mutex));
      delegate.clear();
    }

    @Override
    public Object[] toArray() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.toArray();
    }

    @Override

                } catch (final Exception e) {
                    logger.warn("Failed to close the crawler.", e);
                }
            });
        }
        crawlerList.clear();
        crawlerStatusList.clear();

        // put cralwing info
        final CrawlingInfoHelper crawlingInfoHelper = ComponentUtil.getCrawlingInfoHelper();

        assertThat(list.remove("1"), is(true));
        assertThat(list.remove(null), is(true));
        list.clear();
        list.addLast("1");
        list.addLast("2");
        list.addLast("3");
        list.remove(1);
        assertThat(list.get(0), is("1"));
        assertThat(list.get(1), is("3"));

        list.clear();
        list.addLast("1");
        list.addLast("2");
        list.addLast("3");

     */
    public boolean getContextFlag(final int flag) {
        return (getContextFlags() & flag) == flag;
    }

    /**
     * Sets or clears a specific context flag
     * @param flag the context flag to set or clear
     * @param value true to set the flag, false to clear it
     */
    public void setContextFlag(final int flag, final boolean value) {