/**
* Perform an operation on an object property.
*
* @param string $key Key to perform an operation upon.
* @param FieldOperation $operation Operation to perform.
*
* @return null
* @ignore
*/
public function _performOperation($key, FieldOperation $operation)
{
$oldValue = null;
if (isset($this->estimatedData[$key])) {
$oldValue = $this->estimatedData[$key];
}
$newValue = $operation->_apply($oldValue, $this, $key);
if ($newValue !== null) {
$this->estimatedData[$key] = $newValue;
} else {
if (isset($this->estimatedData[$key])) {
unset($this->estimatedData[$key]);
}
}
if (isset($this->operationSet[$key])) {
$oldOperations = $this->operationSet[$key];
$newOperations = $operation->_mergeWithPrevious($oldOperations);
$this->operationSet[$key] = $newOperations;
} else {
$this->operationSet[$key] = $operation;
}
$this->dataAvailability[$key] = true;
}
