/**
* Recursively create an SMWSparqlCondition from an SMWDisjunction.
*
* @param $description SMWDisjunction
* @param $joinVariable string name, see buildSparqlCondition()
* @param $orderByProperty mixed SMWDIProperty or null, see buildSparqlCondition()
* @return SMWSparqlCondition
*/
protected function buildDisjunctionCondition(SMWDisjunction $description, $joinVariable, $orderByProperty)
{
$subDescriptions = $description->getDescriptions();
if (count($subDescriptions) == 0) {
// empty disjunction: false
return new SMWSparqlFalseCondition();
} elseif (count($subDescriptions) == 1) {
// disjunction with one element
return $this->buildSparqlCondition(reset($subDescriptions), $joinVariable, $orderByProperty);
}
// else: proper disjunction; note that orderVariables found in subconditions cannot be used for the whole disjunction
$unionCondition = '';
$filter = '';
$namespaces = $weakConditions = array();
$hasSafeSubconditions = false;
foreach ($subDescriptions as $subDescription) {
$subCondition = $this->buildSparqlCondition($subDescription, $joinVariable, null);
if ($subCondition instanceof SMWSparqlFalseCondition) {
// empty parts in a disjunction can be ignored
} elseif ($subCondition instanceof SMWSparqlTrueCondition) {
return $this->buildTrueCondition($joinVariable, $orderByProperty);
} elseif ($subCondition instanceof SMWSparqlWhereCondition) {
$hasSafeSubconditions = $hasSafeSubconditions || $subCondition->isSafe();
$unionCondition .= ($unionCondition ? ' UNION ' : '') . "{\n" . $subCondition->condition . "}";
} elseif ($subCondition instanceof SMWSparqlFilterCondition) {
$filter .= ($filter ? ' || ' : '') . $subCondition->filter;
} elseif ($subCondition instanceof SMWSparqlSingletonCondition) {
$hasSafeSubconditions = $hasSafeSubconditions || $subCondition->isSafe();
$matchElement = $subCondition->matchElement;
$matchElementName = SMWTurtleSerializer::getTurtleNameForExpElement($matchElement);
if ($matchElement instanceof SMWExpNsResource) {
$namespaces[$matchElement->getNamespaceId()] = $matchElement->getNamespace();
}
if ($subCondition->condition === '') {
$filter .= ($filter ? ' || ' : '') . "?{$joinVariable} = {$matchElementName}";
} else {
$unionCondition .= ($unionCondition ? ' UNION ' : '') . "{\n" . $subCondition->condition . " FILTER( ?{$joinVariable} = {$matchElementName} ) }";
}
}
$namespaces = array_merge($namespaces, $subCondition->namespaces);
$weakConditions = array_merge($weakConditions, $subCondition->weakConditions);
}
if ($unionCondition === '' && $filter === '') {
return new SMWSparqlFalseCondition();
} elseif ($unionCondition === '') {
$result = new SMWSparqlFilterCondition($filter, $namespaces);
} elseif ($filter === '') {
$result = new SMWSparqlWhereCondition($unionCondition, $hasSafeSubconditions, $namespaces);
} else {
$subJoinVariable = $this->getNextVariable();
$unionCondition = str_replace("?{$joinVariable} ", "?{$subJoinVariable} ", $unionCondition);
$filter .= " || ?{$joinVariable} = ?{$subJoinVariable}";
$result = new SMWSparqlWhereCondition("OPTIONAL { {$unionCondition} }\n FILTER( {$filter} )\n", false, $namespaces);
}
$result->weakConditions = $weakConditions;
$this->addOrderByDataForProperty($result, $joinVariable, $orderByProperty);
return $result;
}
public function prune( &$maxsize, &$maxdepth, &$log ) {
if ( $maxsize <= 0 ) {
$log[] = $this->getQueryString();
return new SMWThingDescription();
}
$prunelog = array();
$newdepth = $maxdepth;
$result = new SMWDisjunction();
foreach ( $this->m_descriptions as $desc ) {
$restdepth = $maxdepth;
$result->addDescription( $desc->prune( $maxsize, $restdepth, $prunelog ) );
$newdepth = min( $newdepth, $restdepth );
}
if ( count( $result->getDescriptions() ) > 0 ) {
$log = array_merge( $log, $prunelog );
$maxdepth = $newdepth;
if ( count( $result->getDescriptions() ) == 1 ) { // simplify unary disjunctions!
$descriptions = $result->getDescriptions();
$result = array_shift( $descriptions );
}
$result->setPrintRequests( $this->getPrintRequests() );
return $result;
} else {
$log[] = $this->getQueryString();
$result = new SMWThingDescription();
$result->setPrintRequests( $this->getPrintRequests() );
return $result;
}
}
