Wait for AJAX call to complete in WebDriver

Sometimes in our web application only part of the web page gets loaded upon certain actions, at that time actually an ajax call happens and depending upon the ajax response the page part loads. So in this case we need to wait till the ajax call is completed to test anything on that part of the webpage, if you don't want to do that by waiting for a specific element to be available. Below is the code that waits till the ajax calls completed:

/**
 * Waits until there are no more active ajax connection and until the
 * specified timeoutInSeconds is timeout
 * 
 * @param timeoutInSeconds
 */
public void waitForAjax(long timeoutInSeconds) {
 log.info("Checking active ajax calls by calling jquery.active");
 try {
  if (driver instanceof JavascriptExecutor) {
   JavascriptExecutor jsDriver = (JavascriptExecutor) driver;

   for (int i = 0; i < timeoutInSeconds; i++) {
    Object numberOfAjaxConnections = jsDriver
      .executeScript("return jQuery.active");
    // return should be a number
    if (numberOfAjaxConnections instanceof Long) {
     Long n = (Long) numberOfAjaxConnections;
     log.info("Number of active jquery ajax calls: " + n);
     if (n.longValue() == 0L)
      break;
    }
    Thread.sleep(1000);// 1 second sleep
   }
  } else {
   log.error("Web driver: " + driver
     + " cannot execute javascript");
  }
 } catch (Exception e) {
  log.error("Failed to wait for ajax response: " + e);
 }
}

In this code snippet we are checking the number of active Ajax connections by executing the javascript code jQuery.active then depending upon the result we are waiting for the ajax calls to complete until the timeout specified in timeoutInSeconds paameter