Piwik\DataTable::getSerialized PHP 메소드

    public function getSerialized($maximumRowsInDataTable = null, $maximumRowsInSubDataTable = null, $columnToSortByBeforeTruncation = null)
    {
        static $depth = 0;
        // make sure subtableIds are consecutive from 1 to N
        static $subtableId = 0;
        if ($depth > self::$maximumDepthLevelAllowed) {
            $depth = 0;
            $subtableId = 0;
            throw new Exception("Maximum recursion level of " . self::$maximumDepthLevelAllowed . " reached. Maybe you have set a DataTable\\Row with an associated DataTable belonging already to one of its parent tables?");
        }
        if (!is_null($maximumRowsInDataTable)) {
            $this->filter('Truncate', array($maximumRowsInDataTable - 1, DataTable::LABEL_SUMMARY_ROW, $columnToSortByBeforeTruncation, $filterRecursive = false));
        }
        $consecutiveSubtableIds = array();
        $forcedId = $subtableId;
        // For each row, get the serialized row
        // If it is associated to a sub table, get the serialized table recursively ;
        // but returns all serialized tables and subtable in an array of 1 dimension
        $aSerializedDataTable = array();
        foreach ($this->rows as $id => $row) {
            $subTable = $row->getSubtable();
            if ($subTable) {
                $consecutiveSubtableIds[$id] = ++$subtableId;
                $depth++;
                $aSerializedDataTable = $aSerializedDataTable + $subTable->getSerialized($maximumRowsInSubDataTable, $maximumRowsInSubDataTable, $columnToSortByBeforeTruncation);
                $depth--;
            } else {
                $row->removeSubtable();
            }
        }
        // if the datatable is the parent we force the Id at 0 (this is part of the specification)
        if ($depth == 0) {
            $forcedId = 0;
            $subtableId = 0;
        }
        // we then serialize the rows and store them in the serialized dataTable
        $rows = array();
        foreach ($this->rows as $id => $row) {
            if (array_key_exists($id, $consecutiveSubtableIds)) {
                $backup = $row->subtableId;
                $row->subtableId = $consecutiveSubtableIds[$id];
                $rows[$id] = $row->export();
                $row->subtableId = $backup;
            } else {
                $rows[$id] = $row->export();
            }
        }
        if (isset($this->summaryRow)) {
            $rows[self::ID_SUMMARY_ROW] = $this->summaryRow->export();
        }
        $aSerializedDataTable[$forcedId] = serialize($rows);
        unset($rows);
        return $aSerializedDataTable;
    }

 private function generateDataTableWithManySubtables($numSubtables)
 {
     $dataTable = new DataTable();
     for ($i = 1; $i <= $numSubtables; $i++) {
         $row = new Row(array(Row::COLUMNS => array('label' => 'Label Test ' . $i, 'nb_visits' => $i)));
         $subtable = DataTable::makeFromSimpleArray(array(array('label' => 'subtable' . $i, 'nb_visits' => $i)));
         $row->setSubtable($subtable);
         $dataTable->addRow($row);
     }
     return $dataTable->getSerialized();
 }