@Override
  protected abstract Deque<E> delegate();

  @Override
  public void addFirst(@ParametricNullness E e) {
    delegate().addFirst(e);
  }

  @Override
  public void addLast(@ParametricNullness E e) {
    delegate().addLast(e);
  }

  @Override
  public Iterator<E> descendingIterator() {
    return delegate().descendingIterator();
  }

  @Override
  @ParametricNullness
  public E getFirst() {

        int num = 10000;

        addDocument(indexName, client, num);

        ESSourceReader reader = new ESSourceReader(client, settings, indexName);
        reader.setScrollSize(1000);
        reader.addSort(SortBuilders.fieldSort("field2"));
        int count = 0;
        int prev = -1;
        Map<String, Object> source;
        while ((source = reader.read()) != null) {

        header.previous = header;
        for (int i = 0; i < size; i++) {
            addLast((E) s.readObject());
        }
    }

    @Override
    public Object clone() {
        final SLinkedList<E> copy = new SLinkedList<>();
        for (Entry e = header.next; e != header; e = e.next) {
            copy.addLast(e.element);
        }
        return copy;
    }

    /**
     * 配列に変換します。

type Writer interface {
	WriteByte(byte) error
	WriteString(string) (int, error)
}

// Builder builder interface
type Builder interface {
	Writer
	WriteQuoted(field interface{})
	AddVar(Writer, ...interface{})
	AddError(error) error
}

// Clause
type Clause struct {
	Name                string // WHERE
	BeforeExpression    Expression
	AfterNameExpression Expression

        }
        this.limitOfDocumentSize = limitOfDocumentSize;
    }

    public void setQuery(final QueryBuilder queryBuilder) {
        this.queryBuilder = queryBuilder;
    }

    public void addSort(final SortBuilder<?> sortBuilder) {
        sortList.add(sortBuilder);
    }

    public void setLimitDocNumPercentage(final String limitPercentage) {
        if (logger.isInfoEnabled()) {

}

// Quote returns quoted value
func (stmt *Statement) Quote(field interface{}) string {
	var builder strings.Builder
	stmt.QuoteTo(&builder, field)
	return builder.String()
}

// AddVar add var
func (stmt *Statement) AddVar(writer clause.Writer, vars ...interface{}) {
	for idx, v := range vars {
		if idx > 0 {
			writer.WriteByte(',')
		}

		switch v := v.(type) {
		case sql.NamedArg:

		}
		builder.WriteByte(')')

		builder.WriteString(" VALUES ")

		for idx, value := range values.Values {
			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteByte('(')
			builder.AddVar(builder, value...)
			builder.WriteByte(')')
		}
	} else {
		builder.WriteString("DEFAULT VALUES")
	}
}

// MergeClause merge values clauses
func (values Values) MergeClause(clause *Clause) {

            if (queryBuilder != null) {
                builder.setQuery(queryBuilder);
            }
            _conditionQuery.getFieldSortBuilderList().forEach(sort -> {
                builder.addSort(sort);
            });
        }

        if (_conditionAggregation != null) {
            _conditionAggregation.getAggregationBuilderList().forEach(builder::addAggregation);
        }

            if (queryBuilder != null) {
                builder.setQuery(queryBuilder);
            }
            _conditionQuery.getFieldSortBuilderList().forEach(sort -> {
                builder.addSort(sort);
            });
        }

        if (_conditionAggregation != null) {
            _conditionAggregation.getAggregationBuilderList().forEach(builder::addAggregation);
        }

                            flist.toArray(new FunctionScoreQueryBuilder.FilterFunctionBuilder[flist.size()]))
                    .boostMode(CombineFunction.MULTIPLY));
            reader.addSort(SortBuilders.fieldSort(fessConfig.getIndexFieldClickCount()));
            reader.addSort(SortBuilders.scoreSort());
            return reader;
        }, docPerReq, () -> {
            systemHelper.calibrateCpuLoad();
            ThreadUtil.sleep(interval);