In order to leverage the TestNG parallel testing features, users must create a separate thread for each driver instance to control event processing requests. This is done in Java using the ThreadLocal<T> class. By declaring variables with this class, each thread has its own initialized copy of the variable, and can return specifics of that session. The following variables are declared in the singleton driver class, and have getter and setter methods to retrieve the session ID, browser, platform, and version:

private ThreadLocal<WebDriver> webDriver = new ThreadLocal<WebDriver>();
private ThreadLocal<AppiumDriver<MobileElement>> mobileDriver = new ThreadLocal<AppiumDriver<MobileElement>>();

private ThreadLocal<String> sessionId = new ThreadLocal<String>();
private ThreadLocal<String> sessionBrowser = new ThreadLocal<String>();
private ThreadLocal<String> sessionPlatform = new ThreadLocal<String>();
private ThreadLocal<String> sessionVersion = new ThreadLocal<String>();

Key points:

<suite name="Parallel_Test_Suite" preserve-order="true" parallel="classes" thread-count="10">

These are examples of the getter methods for the driver class:

/**
 * getSessionId method gets the browser or mobile id
 * of the active session
 *
 * @return String
 */
public String getSessionId() {
    return sessionId.get();
}

/**
 * getSessionBrowser method gets the browser or mobile type
 * of the active session
 *
 * @return String
 */
public String getSessionBrowser() {
    return sessionBrowser.get();
}

/**
 * getSessionVersion method gets the browser or mobile version
 * of the active session
 * 
 * @return String
 */
public String getSessionVersion() {
    return sessionVersion.get();
}

/**
 * getSessionPlatform method gets the browser or mobile platform
 * of the active session
 *
 * @return String
 */
public String getSessionPlatform() {
    return sessionPlatform.get();
}

How to set:

The session ID, browser, version, and platform can be set during driver creation in the setDriver methods as follows:

getEnv = "local";
getPlatform = platform;

if ( browser.equalsIgnoreCase("iphone") ||
     browser.equalsIgnoreCase("android") ) {

    sessionId.set(((IOSDriver<MobileElement>)
    mobileDriver.get()).getSessionId().toString());

    sessionId.set(((AndroidDriver<MobileElement>)
    mobileDriver.get()).getSessionId().toString());

    sessionBrowser.set(browser);
    sessionVersion.set(caps.getCapability("deviceName").toString());
    sessionPlatform.set(getPlatform);
}

else {
    sessionId.set(((RemoteWebDriver) webDriver.get())
             .getSessionId().toString());

    sessionBrowser.set(caps.getBrowserName());
    sessionVersion.set(caps.getVersion());
    sessionPlatform.set(getPlatform);
}