Method edit

/**
 * Method to edit an existing record.
 *
 * @param   string  $key     The name of the primary key of the URL variable.
 * @param   string  $urlVar  The name of the URL variable if different from the primary key
 *                           (sometimes required to avoid router collisions).
 *
 * @return  boolean  True if access level check and checkout passes, false otherwise.
 *
 * @since   1.6
 */
public function edit($key = null, $urlVar = null)
{
    // Do not cache the response to this, its a redirect, and mod_expires and google chrome browser bugs cache it forever!
    Factory::getApplication()->allowCache(false);
    $model = $this->getModel();
    $table = $model->getTable();
    $cid = (array) $this->input->post->get('cid', array(), 'int');
    $context = "{$this->option}.edit.{$this->context}";
    // Determine the name of the primary key for the data.
    if (empty($key)) {
        $key = $table->getKeyName();
    }
    // To avoid data collisions the urlVar may be different from the primary key.
    if (empty($urlVar)) {
        $urlVar = $key;
    }
    // Get the previous record id (if any) and the current record id.
    $recordId = (int) (\count($cid) ? $cid[0] : $this->input->getInt($urlVar));
    $checkin = $table->hasField('checked_out');
    // Access check.
    if (!$this->allowEdit(array($key => $recordId), $key)) {
        $this->setMessage(Text::_('JLIB_APPLICATION_ERROR_EDIT_NOT_PERMITTED'), 'error');
        $this->setRedirect(Route::_('index.php?option=' . $this->option . '&view=' . $this->view_list . $this->getRedirectToListAppend(), false));
        return false;
    }
    // Attempt to check-out the new record for editing and redirect.
    if ($checkin && !$model->checkout($recordId)) {
        // Check-out failed, display a notice but allow the user to see the record.
        $this->setMessage(Text::sprintf('JLIB_APPLICATION_ERROR_CHECKOUT_FAILED', $model->getError()), 'error');
        $this->setRedirect(Route::_('index.php?option=' . $this->option . '&view=' . $this->view_item . $this->getRedirectToItemAppend($recordId, $urlVar), false));
        return false;
    } else {
        // Check-out succeeded, push the new record id into the session.
        $this->holdEditId($context, $recordId);
        Factory::getApplication()->setUserState($context . '.data', null);
        $this->setRedirect(Route::_('index.php?option=' . $this->option . '&view=' . $this->view_item . $this->getRedirectToItemAppend($recordId, $urlVar), false));
        return true;
    }
}