/**
* Check if a given instance of \Saft\Rdf\Node is equal to this instance.
*
* @param \Saft\Rdf\Node $toCompare
* @return boolean True, if both instances are semantically equal, false otherwise.
*/
public function equals(\Saft\Rdf\Node $toCompare)
{
if ($toCompare instanceof BlankNode) {
return $this->getBlankId() === $toCompare->getBlankId();
}
return false;
}
/**
* Returns given Node instance in SPARQL format, which is in NQuads or as Variable
*
* @param Node $node Node instance to format.
* @param string $var The variablename, which should be used, if the node is not concrete
* @return string Either NQuad notation (if node is concrete) or as variable.
*/
public static function getNodeInSparqlFormat(Node $node, $var = null)
{
if ($node->isConcrete()) {
return $node->toNQuads();
}
if ($var == null) {
$var = uniqid('tempVar');
}
return '?' . $var;
}
public function createRedlandNodeFromNode(Node $node)
{
if ($node instanceof NamedNode || $node instanceof Literal || $node instanceof BlankNode) {
return $node->getRedlandNode();
} elseif ($node->isNamed()) {
return $this->createNamedNode($node->getUri())->getRedlandNode();
} elseif ($node->isLiteral()) {
return $this->createLiteral($node->getValue(), $node->getDatatype(), $node->getLanguage())->getRedlandNode();
} elseif ($node->isBlank()) {
return $this->createBlankNode($node->getBlankId())->getRedlandNode();
}
throw new \Exception("This node type (" . get_class($node) . ") is not supported by Redland backend");
}
/**
* Returns true or false depending on whether or not the statements pattern has any matches in the given graph.
*
* @param Statement $Statement It can be either a concrete or pattern-statement.
* @param Node $graph optional Overrides target graph.
* @param array $options optional It contains key-value pairs and should provide additional
* introductions for the store and/or its adapter(s).
* @return boolean Returns true if at least one match was found, false otherwise.
*/
public function hasMatchingStatement(Statement $statement, Node $graph = null, array $options = array())
{
if (null !== $graph) {
$graphUri = $graph->getUri();
// no graph information given, use default graph
} elseif (null === $graph && null === $statement->getGraph()) {
$graphUri = 'http://saft/defaultGraph/';
// no graph given, use graph information from $statement
} elseif (null === $graph && $statement->getGraph()->isNamed()) {
$graphUri = $statement->getGraph()->getUri();
// no graph given, use graph information from $statement
} elseif (null === $graph && false == $statement->getGraph()->isNamed()) {
$graphUri = 'http://saft/defaultGraph/';
}
// use hash to differenciate between statements (no doublings allowed)
$statementHash = hash('sha256', json_encode($statement));
// check it
return isset($this->statements[$graphUri][$statementHash]);
}
/**
* Adds multiple Statements to (default-) graph. It overrides parents addStatements because ARC2 only
* supports SPARQL+ and not SPARQL Update 1.1, which means an INSERT INTO query has to look like:
* INSERT INTO <http://graph/> { triple ... }.
*
* @param StatementIterator|array $statements StatementList instance must contain Statement
* instances which are 'concret-' and not
* 'pattern'-statements.
* @param Node $graph optional Overrides target graph. If set, all statements
* will be add to that graph, if it is available.
* @param array $options optional Key-value pairs which provide additional
* introductions for the store and/or its
* adapter(s).
*/
public function addStatements($statements, Node $graph = null, array $options = array())
{
$graphUriToUse = null;
foreach ($statements as $statement) {
if (!$statement->isConcrete()) {
// non-concrete Statement instances not allowed
// we have to undo the transaction somehow
throw new \Exception('At least one Statement is not concrete');
}
if (null !== $graph) {
// given $graph forces usage of it and not the graph from the statement instance
$graphUriToUse = $graph->getUri();
} elseif (null !== $statement->getGraph()) {
// use graphUri from statement
$graphUriToUse = $statement->getGraph()->getUri();
}
// else: non-concrete Statement instances not allowed
$this->query('INSERT INTO <' . $graphUriToUse . '> {' . SparqlUtils::getNodeInSparqlFormat($statement->getSubject()) . ' ' . SparqlUtils::getNodeInSparqlFormat($statement->getPredicate()) . ' ' . SparqlUtils::getNodeInSparqlFormat($statement->getObject()) . ' . ' . '}', $options);
}
}
/**
* Checks if a certain graph is available in the store.
*
* @param Node $graph URI of the graph to check if it is available.
* @return boolean True if graph is available, false otherwise.
*/
public function isGraphAvailable(Node $graph)
{
$graphs = $this->getGraphs();
return isset($graphs[$graph->getUri()]);
}
/**
* Returns true or false depending on whether or not the statements pattern
* has any matches in the given graph.
*
* @param Statement $Statement It can be either a concrete or pattern-statement.
* @param Node $graph optional Overrides target graph.
* @param array $options optional It contains key-value pairs and should provide additional
* introductions for the store and/or its adapter(s).
* @return boolean Returns true if at least one match was found, false otherwise.
*/
public function hasMatchingStatement(Statement $statement, Node $graph = null, array $options = array())
{
// if $graph was given, but its not a named node, set it to null.
if (null !== $graph && false === $graph->isNamed()) {
$graph = null;
}
// otherwise check, if graph was set in the statement and it is a named node and use it, if so.
if (null === $graph && null !== $statement->getGraph() && true === $statement->getGraph()->isNamed()) {
$graph = $statement->getGraph();
}
$statementIterator = $this->statementIteratorFactory->createIteratorFromArray(array($statement));
$result = $this->query('ASK { ' . $this->sparqlFormat($statementIterator, $graph) . '}', $options);
if (true === is_object($result)) {
return $result->getValue();
} else {
return $result;
}
}
/**
* redirects to the query method.
* Returns true or false depending on whether or not the statements pattern
* has any matches in the given graph.
*
* @param Statement $statement It can be either a concrete or pattern-statement.
* @param Node $graph optional Overrides target graph.
* @param array $options optional It contains key-value pairs and should provide additional
* introductions for the store and/or its adapter(s).
* @return boolean Returns true if at least one match was found, false otherwise.
* @todo cache ask queries
*/
public function hasMatchingStatement(Statement $statement, Node $graph = null, array $options = array())
{
// TODO migrate code to new interface
$graphUri = null;
if ($graph !== null) {
$graphUri = $graph->getUri();
}
// log it
$this->addToLog(array('method' => 'hasMatchingStatement', 'parameter' => array('statement' => $statement, 'graphUri' => $graphUri, 'options' => $options)));
/**
* build matching query and check for cache entry
*/
// create shortcuts for S, P and O
$s = $statement->getSubject();
$p = $statement->getPredicate();
$o = $statement->getObject();
$query = '';
// add filter, if subject is a named node or literal
if (true === $s->isNamed()) {
$query .= 'FILTER (str(?s) = "' . $s->getUri() . '") ';
}
// add filter, if predicate is a named node or literal
if (true === $p->isNamed()) {
$query .= 'FILTER (str(?p) = "' . $p->getUri() . '") ';
}
// add filter, if predicate is a named node or literal
if (true === $o->isNamed()) {
$query .= 'FILTER (str(?o) = "' . $o->getUri() . '") ';
}
if (true == $o->isLiteral()) {
$query .= 'FILTER (str(?o) = ' . $o->getValue() . ') ';
}
$query = 'ASK FROM <' . $graphUri . '> { ?s ?p ?o ' . $query . '}';
$queryCacheContainer = $this->cache->load($query);
// check, if there is a cache entry for this statement
if (null !== $queryCacheContainer) {
return $queryCacheContainer['result'];
// if successor is set, ask it first before run the command yourself.
} elseif ($this->successor instanceof Store) {
$result = $this->successor->hasMatchingStatement($statement, $graph, $options);
$this->saveResult($this->queryFactory->createInstanceByQueryString($query), $result);
return $result;
// dont run command by myself
} else {
throw new \Exception('QueryCache does not support has matching statement calls, only by successor.');
}
}
