/**
* @dataProvider sequencedIdentifiersProvider
*
* @param string $identifier
* @param string $expectedPrefix
* @param string $expectedSequence
* @param string $expectedVariableName
*/
public function testSequencedIdentifiers($identifier, $expectedPrefix, $expectedSequence, $expectedVariableName)
{
$v = new VariableIdentifier($identifier);
$this->assertEquals($identifier, $v->getIdentifier());
$this->assertTrue($v->hasPrefix());
$this->assertTrue($v->hasSequenceNumber());
$this->assertEquals($expectedPrefix, $v->getPrefix());
$this->assertEquals($expectedVariableName, $v->getVariableName());
$this->assertEquals($expectedSequence, $v->getSequenceNumber());
}
/**
* Get the item sessions held by the test session by item reference $identifier.
*
* @param string $identifier An item reference $identifier e.g. Q04. Prefixed or sequenced identifiers e.g. Q04.1.X are considered to be malformed.
* @return AssessmentItemSessionCollection|false A collection of AssessmentItemSession objects or false if no item session could be found for $identifier.
* @throws InvalidArgumentException If the given $identifier is malformed.
*/
public function getAssessmentItemSessions($identifier)
{
try {
$v = new VariableIdentifier($identifier);
if ($v->hasPrefix() === true || $v->hasSequenceNumber() === true) {
$msg = "'{$identifier}' is not a valid item reference identifier.";
throw new InvalidArgumentException($msg, 0);
}
$itemRefs = $this->getAssessmentItemRefs();
if (isset($itemRefs[$identifier]) === false) {
return false;
}
try {
return $this->getAssessmentItemSessionStore()->getAssessmentItemSessions($itemRefs[$identifier]);
} catch (OutOfBoundsException $e) {
return false;
}
} catch (InvalidArgumentException $e) {
$msg = "'{$identifier}' is not a valid item reference identifier.";
throw new InvalidArgumentException($msg, 0, $e);
}
}
/**
* Check if a given variable identified by $offset exists in the global scope
* of the AssessmentTestSession.
*
* @return boolean Whether the variable identified by $offset exists in the current context.
* @throws \OutOfRangeException If $offset is not a simple variable identifier (no prefix, no sequence number).
*/
public function offsetExists($offset)
{
try {
$v = new VariableIdentifier($offset);
if ($v->hasPrefix() === true) {
$msg = "Test existence of a variable in an AssessmentTestSession may only be addressed with simple variable ";
$msg = "identifiers (no prefix, no sequence number). '" . $v->__toString() . "' given.";
throw new OutOfRangeException($msg, 0);
}
$data =& $this->getDataPlaceHolder();
return isset($data[$offset]);
} catch (InvalidArgumentException $e) {
$msg = "'{$offset}' is not a valid variable identifier.";
throw new OutOfRangeException($msg);
}
}
/**
* Perform a branching on a TestPart, AssessmentSection or AssessmentItemRef with
* the given $identifier.
*
* The target will be considered invalid if the following constraints are not fullfilled:
*
* From IMS QTI:
* In the case of an item or section, the target must refer to an item or section in the same
* testPart that has not yet been presented. For testParts, the target must refer to another testPart.
*
* @param string $identifier A QTI Identifier to be the target of the branching.
* @throws \OutOfBoundsException If an error occurs while branching e.g. the $identifier is not referenced in the route or the target is invalid.
* @throws \OutOfRangeException If $identifier is not a valid branching identifier.
*/
public function branch($identifier)
{
try {
$identifier = new VariableIdentifier($identifier);
$id = $identifier->hasPrefix() === false ? $identifier->getVariableName() : $identifier->getPrefix();
$occurence = $identifier->hasPrefix() === false ? 0 : intval($identifier->getVariableName() - 1);
} catch (InvalidArgumentException $e) {
$msg = "The given identifier '{$identifier}' is an invalid branching target.";
throw new OutOfRangeException($msg);
}
// Check for an assessmentItemRef.
$assessmentItemRefs = $this->getAssessmentItemRefs();
if (isset($assessmentItemRefs[$id]) === true) {
$assessmentItemRefMap = $this->getAssessmentItemRefMap();
$targetRouteItems = $assessmentItemRefMap[$assessmentItemRefs[$id]];
if ($targetRouteItems[$occurence]->getTestPart() !== $this->current()->getTestPart()) {
// From IMS QTI:
// In case of an item or section, the target must refer to an item or section
// in the same testPart [...]
$msg = "Branchings to items outside of the current testPart is forbidden by the QTI 2.1 specification.";
throw new OutOfBoundsException($msg);
}
$this->setPosition($this->getRouteItemPosition($targetRouteItems[$occurence]));
return;
}
// Check for an assessmentSection.
$assessmentSectionIdentifierMap = $this->getAssessmentSectionIdentifierMap();
if (isset($assessmentSectionIdentifierMap[$id]) === true) {
if ($assessmentSectionIdentifierMap[$id][0]->getTestPart() !== $this->current()->getTestPart()) {
// From IMS QTI:
// In case of an item or section, the target must refer to an item or section
// in the same testPart [...]
$msg = "Branchings to assessmentSections outside of the current testPart is forbidden by the QTI 2.1 specification.";
throw new OutOfBoundsException($msg);
}
// We branch to the first RouteItem belonging to the section.
$this->setPosition($this->getRouteItemPosition($assessmentSectionIdentifierMap[$id][0]));
return;
}
// Check for a testPart.
$testPartIdentifierMap = $this->getTestPartIdentifierMap();
if (isset($testPartIdentifierMap[$id]) === true) {
// We branch to the first RouteItem belonging to the testPart.
if ($testPartIdentifierMap[$id][0]->getTestPart() === $this->current()->getTestPart()) {
// From IMS QTI:
// For testParts, the target must refer to another testPart.
$msg = "Cannot branch to the same testPart.";
throw new OutOfBoundsException($msg);
}
// We branch to the first RouteItem belonging to the testPart.
$this->setPosition($this->getRouteItemPosition($testPartIdentifierMap[$id][0]));
return;
}
// No such identifier referenced in the route, cannot branch.
$msg = "No such identifier '{$id}' found in the route for branching.";
throw new OutOfBoundsException($msg);
}
/**
* Process the Variable expression.
*
* * If the requested variable does not exist, NULL is returned.
* * In a test context, if the requested weight does not exist, the raw value of the variable is returned.
*
* @returns null|mixed The value of the target variable or NULL if the variable does not exist.
* @throws \qtism\runtime\expressions\ExpressionProcessingException
*/
public function process()
{
$state = $this->getState();
$variableIdentifier = $this->getExpression()->getIdentifier();
$weightIdentifier = $this->getExpression()->getWeightIdentifier();
$variable = $state->getVariable($variableIdentifier);
if (empty($variable)) {
return null;
}
$variableValue = $state[$variableIdentifier];
if ($variable->isNull()) {
return $variableValue;
// Even if empty string, it is considered by QTI as null.
}
// We have a value for this variable, is it weighted?
if ($state instanceof AssessmentTestSession) {
try {
$vIdentifier = new VariableIdentifier($variableIdentifier);
if ($vIdentifier->hasPrefix() === true && empty($weightIdentifier) === false) {
$weight = $state->getWeight($vIdentifier->getPrefix() . '.' . $weightIdentifier);
$baseType = $variableValue->getBaseType();
$cardinality = $variableValue->getCardinality();
// From IMS QTI:
// Weights only apply to item variables with base types integer and float.
// If the item variable is of any other type the weight is ignored.
if (!empty($weight) && ($baseType === BaseType::INTEGER || $baseType === BaseType::FLOAT)) {
if ($cardinality === Cardinality::SINGLE) {
return new Float($variableValue->getValue() * $weight->getValue());
} elseif ($cardinality === Cardinality::MULTIPLE || $cardinality === Cardinality::ORDERED) {
// variableValue is an object, the weighting should not
// affect the content of the state so a new container is created.
$finalValue = $cardinality === Cardinality::MULTIPLE ? new MultipleContainer(BaseType::FLOAT) : new OrderedContainer(BaseType::FLOAT);
for ($i = 0; $i < count($variableValue); $i++) {
if ($variableValue[$i] !== null) {
$finalValue[] = new Float($variableValue[$i]->getValue() * $weight->getValue());
} else {
$finalValue[] = null;
}
}
return $finalValue;
}
} else {
return $variableValue;
}
} else {
return $variableValue;
}
} catch (InvalidArgumentException $e) {
// Invalid $variableIdentifier.
$msg = "Invalid identifier '{$variableIdentifier}' given for variable identifier.";
throw new ExpressionProcessingException($msg, $this, ExpressionProcessingException::NONEXISTENT_VARIABLE, $e);
}
} else {
return $variableValue;
}
}