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"));

        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());

                    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() {

        QueryBuilder result = request.buildFunctionScoreQuery("test", innerQuery);

        String queryString = result.toString();
        // Should contain docFreq, queryFreq, and userBoost factors (camelCase field names)
        assertTrue("Should contain docFreq", queryString.contains("docFreq"));
        assertTrue("Should contain queryFreq", queryString.contains("queryFreq"));

    }

    private SuggestItem createItem(String text, long docFreq, long queryFreq, float userBoost) {
        String[] texts = { text };
        String[][] readings = { { "reading" } };
        String[] fields = { "field" };

        return new SuggestItem(texts, readings, fields, docFreq, queryFreq, userBoost, new String[0], new String[0], new String[0],
                SuggestItem.Kind.DOCUMENT);

     * <li>Fields, tags, languages, and roles are merged, maintaining uniqueness</li>
     * <li>Kinds are merged, maintaining uniqueness</li>
     * <li>Frequencies (queryFreq, docFreq) are summed</li>
     * <li>Timestamp and userBoost are taken from item2 (newer values)</li>
     * </ul>
     *
     * @param item1 The first SuggestItem (base item)

        SuggestItem item = new SuggestItem(new String[] { "test text" }, new String[][] { { "reading1" }, { "reading2" } },
                new String[] { "field1", "field2" }, 10, // queryFreq
                5, // docFreq
                2.0f, // userBoost
                new String[] { "tag1", "tag2" }, new String[] { "role1" }, new String[] {}, // languages
                SuggestItem.Kind.DOCUMENT);