/**
* Create the OperatorProcessor relevant to the given $expression.
*
* @param \qtism\data\expressions\Expression $expression The Operator object you want to get the processor.
* @param \qtism\runtime\expressions\operators\OperandsCollection $operands The operands to be involved in the Operator object.
* @return \qtism\runtime\expressions\operators\OperatorProcessor An OperatorProcessor object ready to process $expression.
* @throws \qtism\runtime\expressions\operators\OperatorProcessingException If the $operands count is not compliant with the Operator object to be processed.
* @throws \InvalidArgumentException If $expression is not an Operator object.
* @throws \RuntimeException If no relevant OperatorProcessor is found for the given $expression.
*/
public function createProcessor(QtiComponent $expression, OperandsCollection $operands = null)
{
if ($expression instanceof Operator) {
if ($expression instanceof CustomOperator) {
// QTI custom operator. Try to load an autoloaded class by using
// its class attribute value.
if ($expression->hasClass() === true) {
$className = Utils::customOperatorClassToPhpClass($expression->getClass());
if (class_exists($className) === true) {
return new $className($expression, $operands);
} else {
$msg = "No custom operator implementation found for class '" . $expression->getClass() . "'.";
throw new RuntimeException($msg);
}
} else {
$msg = "Only custom operators with a 'class' attribute value can be processed.";
throw new RuntimeException($msg);
}
} else {
// QTI built-in operator.
$qtiClassName = ucfirst($expression->getQtiClassName());
$nsPackage = 'qtism\\runtime\\expressions\\operators\\';
$className = $nsPackage . $qtiClassName . 'Processor';
if (class_exists($className)) {
if (is_null($operands) === true) {
$operands = new OperandsCollection();
}
return new $className($expression, $operands);
} else {
$msg = "No dedicated OperatorProcessor class found for QTI operator '{$qtiClassName}'.";
throw new RuntimeException($msg);
}
}
} else {
$msg = "The OperatorProcessorFactory only accepts to create processors for Operator objects.";
throw new InvalidArgumentException($msg);
}
}
/**
* @see \qtism\data\storage\xml\marshalling\RecursiveMarshaller::marshallChildrenKnown()
*/
protected function marshallChildrenKnown(QtiComponent $component, array $elements)
{
$element = self::getDOMCradle()->createElement($component->getQtiClassName());
foreach ($elements as $elt) {
$element->appendChild($elt);
}
if ($component instanceof CustomOperator) {
if ($component->hasClass() === true) {
self::setDOMElementAttribute($element, 'class', $component->getClass());
}
if ($component->hasDefinition() === true) {
self::setDOMElementAttribute($element, 'definition', $component->getDefinition());
}
// Now, we have to extract the LAX content of the custom operator and put it into
// what we are putting out. (It is possible to have no LAX content at all, it is not mandatory).
$xml = $component->getXml();
$operatorElt = $xml->documentElement->cloneNode(true);
$qtiOperatorElts = self::getChildElementsByTagName($operatorElt, array_merge(self::getOperators(), self::getExpressions()));
foreach ($qtiOperatorElts as $qtiOperatorElt) {
$operatorElt->removeChild($qtiOperatorElt);
}
Utils::importChildNodes($operatorElt, $element);
Utils::importAttributes($operatorElt, $element);
}
return $element;
}