Joomla controller with task example

<?php
/**
 * @version     0.4.0
 * @package     com_cn_reports
 * @copyright   Copyright (C) 2015. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 * @author
 */

// No direct access.
defined('_JEXEC') or die;

jimport('joomla.application.component.controlleradmin');

/**
 * Retailpartnersalesbypartners list controller class.
 */
class Cn_reportsControllerRetailpartnersalesbypartners extends JControllerAdmin
{
    /**
     * Constructor.
     *
     * @param   array  $config  An optional associative array of configuration settings.
     *
     * @see     JController
     * @since   1.6
     */
    public function __construct($config = array())
    {
        parent::__construct($config);

        $this->registerTask('exportcsvcommission', 'exportCsvCommission');
        $this->registerTask('exportcsvoverrides', 'exportCsvOverrides');
    }
    /**
     * Proxy for getModel.
     * @since   1.6
     */
    public function getModel($name = 'retailpartnersalebypartner', $prefix = 'Cn_reportsModel', $config = array())
    {
        $model = parent::getModel($name, $prefix, array('ignore_request' => true));
        return $model;
    }

    public function exportCsvCommission()
    {
        header("Content-type: text/csv");
        header("Content-Disposition: attachment; filename=Commissions.csv");
        header("Pragma: no-cache");
        header("Expires: 0");

        $this->getModel('Retailpartnersalesbypartners')->getCsvCommission();
        jexit();
    }
    public function exportCsvOverrides()
    {
        header("Content-type: text/csv");
        header("Content-Disposition: attachment; filename=Overrides.csv");
        header("Pragma: no-cache");
        header("Expires: 0");

        $this->getModel('Retailpartnersalesbypartners')->getCsvOverrides();
        //      $this->getModel()->getCsvCommission();
        jexit();
    }
    /**
     * Method to save the submitted ordering values for records via AJAX.
     *
     * @return  void
     *
     * @since   3.0
     */
    public function saveOrderAjax()
    {
        // Get the input
        $input = JFactory::getApplication()->input;
        $pks = $input->post->get('cid', array(), 'array');
        $order = $input->post->get('order', array(), 'array');

        // Sanitize the input
        JArrayHelper::toInteger($pks);
        JArrayHelper::toInteger($order);

        // Get the model
        $model = $this->getModel();

        // Save the ordering
        $return = $model->saveorder($pks, $order);

        if ($return)
        {
            echo "1";
        }

        // Close the application
        JFactory::getApplication()->close();
    }



}