/**
* Set the QTI Data Model Rule object to be processed.
*
* @param \qtism\runtime\rules\Rule $rule
* @throws \InvalidArgumentException If $rule is not compliant with the rule processor implementation.
*/
public function setRule(Rule $rule)
{
$expectedType = $this->getRuleType();
if (Reflection::isInstanceOf($rule, $expectedType) === true) {
$this->rule = $rule;
} else {
$procClass = get_class($this);
$givenType = get_class($rule);
$msg = "The {$procClass} Rule Processor only processes {$expectedType} Rule objects, {$givenType} given.";
throw new InvalidArgumentException($msg);
}
}
/**
* Set the QTI Data Model Expression to be processed.
*
* @param \qtism\data\expressions\Expression $expression A QTI Data Model Expression object.
* @throws \InvalidArgumentException If $expression is not a subclass nor implements the Expression type returned by the getExpressionType method.
*/
public function setExpression(Expression $expression)
{
$expectedType = $this->getExpressionType();
if (ReflectionUtils::isInstanceOf($expression, $expectedType) === true) {
$this->expression = $expression;
} else {
$procClass = get_class($this);
$givenType = get_class($expression);
$msg = "The {$procClass} Expression Processor only processes {$expectedType} Expression objects, {$givenType} given.";
throw new InvalidArgumentException($msg);
}
$this->expression = $expression;
}
/**
* Process the setOutcomeValue/setTemplateValue rule.
*
* A RuleProcessingException will be thrown if:
*
* * The variable does not exist.
* * The requested variable is not an OutcomeVariable/TemplateVariable.
* * The variable's baseType does not match the baseType of the affected value.
* * An error occurs while processing the related expression.
*
* @throws \qtism\runtime\rules\RuleProcessingException If one of the error described above arise.
*/
public function process()
{
$state = $this->getState();
$rule = $this->getRule();
$identifier = $rule->getIdentifier();
$var = $state->getVariable($identifier);
if (is_null($var) === true) {
$msg = "No variable with identifier '{$identifier}' to be set in the current state.";
throw new RuleProcessingException($msg, $this, RuleProcessingException::NONEXISTENT_VARIABLE);
} elseif (Reflection::isInstanceOf($var, $this->getVariableType()) === false) {
$msg = "The variable to set '{$identifier}' is not an instance of '" . $this->getVariableType() . "'.";
throw new RuleProcessingException($msg, $this, RuleProcessingException::WRONG_VARIABLE_TYPE);
}
// Process the expression.
// Its result will be the value to set to the target variable.
try {
$expressionEngine = new ExpressionEngine($rule->getExpression(), $state);
$val = $expressionEngine->process();
} catch (ExpressionProcessingException $e) {
$msg = "An error occured while processing the expression bound with the '" . Reflection::shortClassName($rule) . "' rule.";
throw new RuleProcessingException($msg, $this, RuleProcessingException::RUNTIME_ERROR, $e);
}
// The variable exists, its new value is processed.
try {
// juggle a little bit (int -> float, float -> int)
if ($val !== null && $var->getCardinality() === Cardinality::SINGLE) {
$baseType = $var->getBaseType();
if ($baseType === BaseType::INTEGER && $val instanceof Float) {
$val = new Integer(intval($val->getValue()));
} elseif ($baseType === BaseType::FLOAT && $val instanceof Integer) {
$val = new Float(floatval($val->getValue()));
}
}
$var->setValue($val);
} catch (InvalidArgumentException $e) {
$varBaseType = BaseType::getNameByConstant($var->getBaseType()) === false ? 'noBaseType' : BaseType::getNameByConstant($var->getBaseType());
$varCardinality = Cardinality::getNameByConstant($var->getCardinality());
// The affected value does not match the baseType of the variable $var.
$msg = "Unable to set value {$val} to variable '{$identifier}' (cardinality = {$varCardinality}, baseType = {$varBaseType}).";
throw new RuleProcessingException($msg, $this, RuleProcessingException::WRONG_VARIABLE_BASETYPE, $e);
}
}
