public T condition()

in hugegraph-server/hugegraph-core/src/main/java/org/apache/hugegraph/backend/query/ConditionQuery.java [260:321]
60 lines of code
17 McCabe index (conditional complexity)

    public <T> T condition(Object key) {
        List<Object> valuesEQ = InsertionOrderUtil.newList();
        List<Object> valuesIN = InsertionOrderUtil.newList();
        for (Condition c : this.conditions) {
            if (c.isRelation()) {
                Condition.Relation r = (Condition.Relation) c;
                if (r.key().equals(key)) {
                    if (r.relation() == RelationType.EQ) {
                        valuesEQ.add(r.value());
                    } else if (r.relation() == RelationType.IN) {
                        Object value = r.value();
                        assert value instanceof List;
                        valuesIN.add(value);
                    }
                }
            }
        }
        if (valuesEQ.isEmpty() && valuesIN.isEmpty()) {
            return null;
        }
        if (valuesEQ.size() == 1 && valuesIN.isEmpty()) {
            @SuppressWarnings("unchecked")
            T value = (T) valuesEQ.get(0);
            return value;
        }
        if (valuesEQ.isEmpty() && valuesIN.size() == 1) {
            @SuppressWarnings("unchecked")
            T value = (T) valuesIN.get(0);
            return value;
        }

        Set<Object> intersectValues = InsertionOrderUtil.newSet();
        for (Object value : valuesEQ) {
            List<Object> valueAsList = ImmutableList.of(value);
            if (intersectValues.isEmpty()) {
                intersectValues.addAll(valueAsList);
            } else {
                CollectionUtil.intersectWithModify(intersectValues,
                                                   valueAsList);
            }
        }
        for (Object value : valuesIN) {
            @SuppressWarnings("unchecked")
            List<Object> valueAsList = (List<Object>) value;
            if (intersectValues.isEmpty()) {
                intersectValues.addAll(valueAsList);
            } else {
                CollectionUtil.intersectWithModify(intersectValues,
                                                   valueAsList);
            }
        }

        if (intersectValues.isEmpty()) {
            return null;
        }
        E.checkState(intersectValues.size() == 1,
                     "Illegal key '%s' with more than one value: %s",
                     key, intersectValues);
        @SuppressWarnings("unchecked")
        T value = (T) intersectValues.iterator().next();
        return value;
    }