1 files changed, 91 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/QueryEngine/DescriptionInterpreters/ClassDescriptionInterpreter.php b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/QueryEngine/DescriptionInterpreters/ClassDescriptionInterpreter.php
new file mode 100644
index 00000000..e936bf94
--- /dev/null
+++ b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/QueryEngine/DescriptionInterpreters/ClassDescriptionInterpreter.php
@@ -0,0 +1,91 @@
+<?php
+
+namespace SMW\SQLStore\QueryEngine\DescriptionInterpreters;
+
+use SMW\DIProperty;
+use SMW\Query\Language\ClassDescription;
+use SMW\Query\Language\Description;
+use SMW\SQLStore\QueryEngine\DescriptionInterpreter;
+use SMW\SQLStore\QueryEngine\QuerySegment;
+use SMW\SQLStore\QueryEngine\QuerySegmentListBuilder;
+
+/**
+ * @license GNU GPL v2+
+ * @since 2.2
+ *
+ * @author Markus Krötzsch
+ * @author Jeroen De Dauw
+ * @author mwjames
+ */
+class ClassDescriptionInterpreter implements DescriptionInterpreter {
+
+	/**
+	 * @var QuerySegmentListBuilder
+	 */
+	private $querySegmentListBuilder;
+
+	/**
+	 * @since 2.2
+	 *
+	 * @param QuerySegmentListBuilder $querySegmentListBuilder
+	 */
+	public function __construct( QuerySegmentListBuilder $querySegmentListBuilder ) {
+		$this->querySegmentListBuilder = $querySegmentListBuilder;
+	}
+
+	/**
+	 * @since 2.2
+	 *
+	 * @return boolean
+	 */
+	public function canInterpretDescription( Description $description ) {
+		return $description instanceof ClassDescription;
+	}
+
+	/**
+	 * @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 = [];
+		$cquery->depth = $description->getHierarchyDepth();
+
+		foreach ( $description->getCategories() as $category ) {
+
+			$categoryId = $this->querySegmentListBuilder->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->querySegmentListBuilder->getStore()->findPropertyTableID( new DIProperty( '_INST' ) );
+			$query->joinfield = "$query->alias.s_id";
+			$query->components[$cqid] = "$query->alias.o_id";
+
+			$this->querySegmentListBuilder->addQuerySegment( $cquery );
+		}
+
+		return $query;
+	}
+
+}