public class ScreenService {

    private final String path = SystemUtils.isOsLinux() ? "/home/screens" : "D:/pv";

    public void takeScreenshot(String url) {
        WebDriver driver = null;
        try {
            url = prepareUrl(url);
            checkInBlacklist(url);
            driver = new FirefoxDriver();
            driver.get(url);
            driver.manage().timeouts().implicitlyWait(5000, TimeUnit.MILLISECONDS);
            driver.switchTo().activeElement();

            for(int[] dim : Constants.dimensions) {
                driver.manage().window().setSize(new Dimension(dim[0], dim[1]));
                File scr = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
                FileUtils.copyFile(scr, new File(String.format( "%s/%s-%s.png", path, url, dim[0] )));
            }
            // .. todo
        }
        finally {
            if(driver != null) {
                driver.close();
                driver.quit();
            }
        }
    }
}