public static final String SCORE = "score";
    /** The query frequency field. */
    public static final String QUERY_FREQ = "queryFreq";
    /** The document frequency field. */
    public static final String DOC_FREQ = "docFreq";
    /** The user boost field. */
    public static final String USER_BOOST = "userBoost";
    /** The kinds field. */
    public static final String KINDS = "kinds";
    /** The timestamp field. */

            logger.info("Deleting all suggest items: index={}", index);
        }
        return deleteByQuery(index, QueryBuilders.matchAllQuery());
    }

    /**
     * Deletes document words (words with DOC_FREQ >= 1 that don't have QUERY or USER kinds).
     *
     * @param index The index name
     * @return The SuggestDeleteResponse
     */
    public SuggestDeleteResponse deleteDocumentWords(final String index) {

        Map<String, Object> source = new HashMap<>();
        source.put(FieldNames.TEXT, "test");
        source.put(FieldNames.QUERY_FREQ, 100L);
        source.put(FieldNames.DOC_FREQ, 50L);
        source.put(FieldNames.USER_BOOST, 2.0f);
        source.put(FieldNames.READING_PREFIX + "0", Arrays.asList("reading1"));
        source.put(FieldNames.FIELDS, Arrays.asList("field1"));

        existing.put(FieldNames.DOC_FREQ, 5L);
        existing.put(FieldNames.QUERY_FREQ, 3L);
        existing.put(FieldNames.TIMESTAMP, System.currentTimeMillis());

        Map<String, Object> updated = SuggestItemSerializer.toUpdatedSource(item, existing);

        assertNotNull(updated);
        assertTrue(updated.containsKey(FieldNames.DOC_FREQ));

        map.put(FieldNames.QUERY_FREQ, updatedQueryFreq);

        final long updatedDocFreq = mergeFrequency(existingSource, FieldNames.DOC_FREQ, item.getDocFreq());
        map.put(FieldNames.DOC_FREQ, updatedDocFreq);

        map.put(FieldNames.USER_BOOST, item.getUserBoost());
        map.put(FieldNames.SCORE, (updatedQueryFreq + updatedDocFreq) * item.getUserBoost());

        assertNotNull(map);
        assertEquals("", map.get(FieldNames.TEXT)); // Empty string for empty map
        assertEquals(0L, map.get(FieldNames.QUERY_FREQ));
        assertEquals(0L, map.get(FieldNames.DOC_FREQ));
        assertEquals(1.0f, map.get(FieldNames.USER_BOOST));
        assertNotNull(map.get(FieldNames.READING_PREFIX + "0"));
        assertNotNull(map.get(FieldNames.FIELDS));

                    ScoreFunctionBuilders.weightFactorFunction(prefixMatchWeight)));
        }

        flist.add(new FunctionScoreQueryBuilder.FilterFunctionBuilder(ScoreFunctionBuilders.fieldValueFactorFunction(FieldNames.DOC_FREQ)
                .missing(0.1f)
                .modifier(FieldValueFactorFunction.Modifier.LOG2P)
                .setWeight(1.0F)));

        this.queryFreq = queryFreq;
    }

    /**
     * Sets the document frequency of the suggest item.
     * @param docFreq The document frequency to set.
     */
    public void setDocFreq(final long docFreq) {
        this.docFreq = docFreq;
    }

    /**
     * Sets the user boost of the suggest item.
     * @param userBoost The user boost to set.
     */

     * Returns the number of document words in the suggestion index.
     * @return The number of document words.
     */
    public long getDocumentWordsNum() {
        return getNum(QueryBuilders.rangeQuery(FieldNames.DOC_FREQ).gte(1));
    }

    /**
     * Returns the number of query words in the suggestion index.
     * @return The number of query words.
     */
    public long getQueryWordsNum() {

        },
        "match": "*",
        "match_mapping_type": "string"
      }
    }
  ],
  "properties": {
    "@timestamp": {
      "type": "date",
      "format": "epoch_millis"
    },
    "docFreq": {
      "type": "long"
    },
    "fields": {
      "type": "keyword"
    },
    "kinds": {
      "type": "keyword"
    },
    "queryFreq": {
      "type": "long"
    },
    "roles": {