/**
* Constructs a result graph.
*
* @param array $arVartable A table containing the result vars and their bindings
* @param GraphPattern $constructPattern The CONSTRUCT pattern
* @return MemModel The result graph which matches the CONSTRUCT pattern
*/
function constructGraph($arVartable, $constructPattern)
{
$resultGraph = new MemModel();
if (!$arVartable) {
return $resultGraph;
}
$tp = $constructPattern->getTriplePatterns();
$bnode = 0;
foreach ($arVartable as $value) {
foreach ($tp as $triple) {
$sub = $triple->getSubject();
$pred = $triple->getPredicate();
$obj = $triple->getObject();
if (is_string($sub) && $sub[1] == '_') {
$sub = new BlankNode("_bN" . $bnode);
}
if (is_string($pred) && $pred[1] == '_') {
$pred = new BlankNode("_bN" . $bnode);
}
if (is_string($obj) && $obj[1] == '_') {
$obj = new BlankNode("_bN" . $bnode);
}
if (is_string($sub)) {
$sub = $value[$sub];
}
if (is_string($pred)) {
$pred = $value[$pred];
}
if (is_string($obj)) {
$obj = $value[$obj];
}
if ($sub !== "" && $pred !== "" && $obj !== "") {
$resultGraph->add(new Statement($sub, $pred, $obj));
}
}
$bnode++;
}
return $resultGraph;
}
/**
* Finds tuples that match one graph pattern.
*
* @param Array $patternlist list that contains the graphPatterns
* @param array $graphlist the graphlist
* @param GraphPattern $graphPattern the pattern which has to be matched
* @return void
*/
protected function matchPattern(&$patternlist, $graphlist, &$graphPattern)
{
// generate an empty result set
$finalRes = null;
// if the GraphPattern has triple patterns
if (count($graphPattern->getTriplePatterns()) > 0) {
// check if the pattern has a GRAPH clause and if this Iri is in $graphlist
$newGraphList = $this->_checkGraphs($graphPattern, $graphlist);
if ($newGraphList) {
$qt = $graphPattern->getTriplePatterns();
$resultSet = $this->findTuplesMatchingOnePattern($qt[0], $newGraphList);
for ($i = 1; $i < count($qt); $i++) {
$rs = $this->findTuplesMatchingOnePattern($qt[$i], $newGraphList);
$resultSet = $this->joinTuples($resultSet, $rs);
if (!$resultSet) {
break;
}
}
if ($finalRes != null) {
$finalRes = $this->joinTuples($finalRes, $resultSet);
} else {
$finalRes = $resultSet;
}
}
}
// dependencies between pattern results
$patternlist[$graphPattern->getId()]['hasOptional'] = 0;
$patternlist[$graphPattern->getId()]['hasUnion'] = 0;
$patternlist[$graphPattern->getId()]['patternResult'] = $finalRes;
$op = $graphPattern->getOptional();
$un = $graphPattern->getUnion();
$patternlist[$graphPattern->getId()]['optionalTo'] = $op;
if (is_int($op)) {
$patternlist[$op]['hasOptional']++;
}
$patternlist[$graphPattern->getId()]['unionWith'] = $un;
if (is_int($un)) {
$patternlist[$un]['hasUnion']++;
}
$constraint = $graphPattern->getConstraints();
if (count($constraint) > 0) {
foreach ($constraint as $constr) {
if ($constr->isOuterFilter()) {
$patternlist[$graphPattern->getId()]['outerFilter'][] = $constr;
$patternlist[$graphPattern->getId()]['innerFilter'][] = null;
} else {
$patternlist[$graphPattern->getId()]['innerFilter'][] = $constr;
$patternlist[$graphPattern->getId()]['outerFilter'][] = null;
}
}
} else {
$patternlist[$graphPattern->getId()]['innerFilter'] = null;
$patternlist[$graphPattern->getId()]['outerFilter'] = null;
}
}
