/**
* @since 2.2
*
* @param Description $description
*
* @return QuerySegment
*/
public function interpretDescription(Description $description)
{
$query = new QuerySegment();
$cqid = QuerySegment::$qnum;
$cquery = new QuerySegment();
$cquery->type = QuerySegment::Q_CLASS_HIERARCHY;
$cquery->joinfield = array();
foreach ($description->getCategories() as $category) {
$categoryId = $this->queryBuilder->getStore()->getObjectIds()->getSMWPageID($category->getDBkey(), NS_CATEGORY, $category->getInterwiki(), '');
if ($categoryId != 0) {
$cquery->joinfield[] = $categoryId;
}
}
if (count($cquery->joinfield) == 0) {
// Empty result.
$query->type = QuerySegment::Q_VALUE;
$query->joinTable = '';
$query->joinfield = '';
} else {
// Instance query with disjunction of classes (categories)
$query->joinTable = $this->queryBuilder->getStore()->findPropertyTableID(new DIProperty('_INST'));
$query->joinfield = "{$query->alias}.s_id";
$query->components[$cqid] = "{$query->alias}.o_id";
$this->queryBuilder->addQuerySegmentForId($cqid, $cquery);
}
return $query;
}
/**
* Create an Condition from an ClassDescription.
*
* @param ClassDescription $description
* @param string $joinVariable
* @param DIProperty|null $orderByProperty
*
* @return Condition
*/
public function buildCondition(Description $description, $joinVariable, $orderByProperty = null)
{
list($condition, $namespaces) = $this->mapCategoriesToConditionElements($description->getCategories(), $joinVariable);
// empty disjunction: always false, no results to order
if ($condition === '') {
return new FalseCondition();
}
$result = new WhereCondition($condition, true, $namespaces);
$this->compoundConditionBuilder->addOrderByDataForProperty($result, $joinVariable, $orderByProperty, DataItem::TYPE_WIKIPAGE);
return $result;
}