protected static List constructShardConditions()

in hugegraph-core/src/main/java/org/apache/hugegraph/backend/tx/GraphIndexTransaction.java [1289:1380]
71 lines of code
14 McCabe index (conditional complexity)

    protected static List<Condition> constructShardConditions(
                                     ConditionQuery query,
                                     List<Id> fields,
                                     HugeKeys key) {
        List<Condition> conditions = new ArrayList<>(2);
        boolean hasRange = false;
        int processedCondCount = 0;
        List<Object> prefixes = new ArrayList<>();

        for (Id field : fields) {
            List<Condition> fieldConds = query.userpropConditions(field);
            processedCondCount += fieldConds.size();
            if (fieldConds.isEmpty()) {
                break;
            }

            RangeConditions range = new RangeConditions(fieldConds);
            if (!range.hasRange()) {
                E.checkArgument(range.keyEq() != null,
                                "Invalid query: %s", query);
                prefixes.add(range.keyEq());
                continue;
            }

            if (range.keyMin() != null) {
                RelationType type = range.keyMinEq() ?
                                    RelationType.GTE : RelationType.GT;
                conditions.add(shardFieldValuesCondition(key, prefixes,
                                                         range.keyMin(),
                                                         type));
            } else {
                assert range.keyMax() != null;
                Object num = range.keyMax();
                num = NumericUtil.minValueOf(NumericUtil.isNumber(num) ?
                                             num.getClass() : Long.class);
                conditions.add(shardFieldValuesCondition(key, prefixes, num,
                                                         RelationType.GTE));
            }

            if (range.keyMax() != null) {
                RelationType type = range.keyMaxEq() ?
                                    RelationType.LTE : RelationType.LT;
                conditions.add(shardFieldValuesCondition(key, prefixes,
                                                         range.keyMax(), type));
            } else {
                Object num = range.keyMin();
                num = NumericUtil.maxValueOf(NumericUtil.isNumber(num) ?
                                             num.getClass() : Long.class);
                conditions.add(shardFieldValuesCondition(key, prefixes, num,
                                                         RelationType.LTE));
            }
            hasRange = true;
            break;
        }

        /*
         * Can't have conditions after range condition for shard index,
         * but SORT_KEYS can have redundant conditions because upper
         * layer can do filter.
         */
        if (key == HugeKeys.FIELD_VALUES &&
            processedCondCount < query.userpropKeys().size()) {
            throw new HugeException("Invalid shard index query: %s", query);
        }
        // 1. First range condition processed, finish shard query conditions
        if (hasRange) {
            return conditions;
        }
        // 2. Shard query without range
        String joinedValues;
        // 2.1 All fields have equal-conditions
        if (prefixes.size() == fields.size()) {
            // Prefix numeric values should be converted to sortable string
            joinedValues = ConditionQuery.concatValues(prefixes);
            conditions.add(Condition.eq(key, joinedValues));
            return conditions;
        }
        // 2.2 Prefix fields have equal-conditions
        /*
         * Append EMPTY to 'values' to ensure FIELD_VALUES suffix
         * with IdGenerator.NAME_SPLITOR
         */
        prefixes.add(ConditionQuery.INDEX_VALUE_EMPTY);
        joinedValues = ConditionQuery.concatValues(prefixes);
        Condition min = Condition.gte(key, joinedValues);
        conditions.add(min);

        // Increase 1 on prefix to get the next prefix
        Condition max = Condition.lt(key, increaseString(joinedValues));
        conditions.add(max);
        return conditions;
    }