* are off).
       */
      KeyList<K, V> keyList = requireNonNull(keyToKeyList.remove(node.key));
      keyList.count = 0;
      modCount++;
    } else {
      // requireNonNull is safe (under the conditions listed in the comment in the branch above).
      KeyList<K, V> keyList = requireNonNull(keyToKeyList.get(node.key));
      keyList.count--;

      if (node.previousSibling == null) {

        }
    }

    public void addExtractor(final List<String> keyList, final Extractor extractor) {
        if (keyList == null || keyList.isEmpty()) {
            throw new CrawlerSystemException("The key list is empty.");
        }
        for (final String key : keyList) {
            addExtractor(key, extractor);
        }
    }

    public Extractor getExtractor(final String key) {

        not(not -> not.setKey_Term(key), opLambda);
    }

    public void setKey_Terms(Collection<String> keyList) {
        setKey_Terms(keyList, null);
    }

    public void setKey_Terms(Collection<String> keyList, ConditionOptionCall<TermsQueryBuilder> opLambda) {
        TermsQueryBuilder builder = regTermsQ("key", keyList);
        if (opLambda != null) {
            opLambda.callback(builder);
        }
    }

public abstract class AbstractExtractor implements Extractor {

    @Resource
    protected CrawlerContainer crawlerContainer;

    public void register(final List<String> keyList) {
        getExtractorFactory().addExtractor(keyList, this);
    }

    protected MimeTypeHelper getMimeTypeHelper() {
        final MimeTypeHelper mimeTypeHelper = crawlerContainer.getComponent("mimeTypeHelper");

  }

  @Override
  ImmutableSet<K> createKeySet() {
    @SuppressWarnings("unchecked")
    ImmutableList<K> keyList =
        (ImmutableList<K>)
            new RegularImmutableMap.KeysOrValuesAsList(alternatingKeysAndValues, keyOffset, size);
    return new RegularImmutableMap.KeySet<>(this, keyList);
  }

  @Override
  boolean isPartialView() {
    return false;
  }

    }
  }

  @Override
  ImmutableSet<K> createKeySet() {
    @SuppressWarnings("unchecked")
    ImmutableList<K> keyList =
        (ImmutableList<K>) new KeysOrValuesAsList(alternatingKeysAndValues, 0, size);
    return new KeySet<K>(this, keyList);
  }

  static final class KeysOrValuesAsList extends ImmutableList<Object> {
    private final transient @Nullable Object[] alternatingKeysAndValues;

    return valueList.size();
  }

  @Override
  public void forEach(BiConsumer<? super K, ? super V> action) {
    checkNotNull(action);
    ImmutableList<K> keyList = keySet.asList();
    for (int i = 0; i < size(); i++) {
      action.accept(keyList.get(i), valueList.get(i));
    }
  }

  @Override
  @CheckForNull
  public V get(@CheckForNull Object key) {
    int index = keySet.indexOf(key);