DataProviders in TestNG are used when we need to iterate over objects. These can be objects created from Java that include complex objects, objects from a property file or database, or simple string objects. Whenever a dataProvider attribute is specified in a @Test annotation, and a method with the annotation @DataProvider exists, the data from this method is passed into the @Test annotated method as a two-dimensional object array.

Let's look at a small example, which is enhanced from our earlier example, where we extracted data into a list of HashMaps. Here we go a step further and read the list of HashMaps in a two-dimensional object array. The following code demonstrates this concept. The code has been split into different sections for readability.

The following code fragment shows all the declarations for this program:

static Object[][] objectArray = {};
  static Object[][] noRecords = {};
  private static String tempParam;
  static Map<String, String> tempMap = new HashMap<String, String>();
  static List<HashMap> tempList = new ArrayList<HashMap>();
  private static List<HashMap> input_data;
  private static String browserName;
  static IActionKeyword actKeyword;
  private static Object actionKeyword;
  private static Object inputData;
  private static Object testcaseID;
  static ICommand command;
  static BrowserInvoker invoker;
  private static WebDriver driver;

  

The following code shows the @Test method with the @Parameters annotation for supplying the browser name and the @AfterTest method:

@Test()
  @Parameters("browserName")
  public static void fetchValues(String param) {
    tempParam = param;
  }

  @AfterTest
  public static void quitBrowser() {
driver.quit();
  }
  

The following code fragment shows the @Test method with the dependsOnMethods annotation and the data provider, Data1. This method has been made to depend on the fetchValues method using the dependsOnMethods attribute:

@Test(dataProvider = "Data1", dependsOnMethods = "fetchValues")
  public void getValues(String testCaseID, String teststepID,
      String action, String data, String keyword) {
    System.out.println("First Extract: " + testCaseID + ": " + 
     teststepID + ": " + action + ": " + data + ": " + keyword);
    List<String> browsers = new ArrayList<String>();

    browsers.add(tempParam);
    String timestamp = new SimpleDateFormat("yyyyMMMddHHmmss")
        .format(new java.util.Date());

    System.out.println("Starting " + browserName + timestamp);
    actionKeyword = keyword;
    inputData = data;
    testcaseID = testCaseID;
    System.out.println("Action Keyword: " + testCaseID);
    System.out.println("Action Data: " + data);

    switch (keyword) {
    case "openbrowser":
      try {
    actKeyword = new OpenBrowser();
    } catch (IOException e) {
    throw new IOException();
    } catch (FilloException e) {
    throw new FilloException("Error in query");
    }
      command = new NewBrowser(actKeyword);
      invoker = new BrowserInvoker(command);
      driver = invoker.open(browsers);
      break;
    case "navigate":
      try {
   actKeyword = new OpenURL();
   } catch (IOException e) {
   throw new IOException();
   } catch (FilloException e) {
   throw new IOException();
   }
      command = new OpenURLCommand(actKeyword);
      NavigatorInvoker invoker1 = new NavigatorInvoker(command);
    driver = invoker1.navigate(driver, data);
      break;
    }
  }

  

The following code shows the actual DataProvider method annotated with the @DataProvider annotation. This annotation is identified with the name Data, which can be referenced in the @Test annotation:

@DataProvider(name = "Data1")
 public static Object[][] exec() {
 String timestamp = new SimpleDateFormat("yyyyMMMddHHmmss")
 .format(new java.util.Date());
 System.out.println("Starting " + tempParam + timestamp);
 Connection conn = null;
 Fillo fillo = new Fillo();
 Recordset rs = null, rs1 = null;
 try {
 conn = fillo.getConnection(System.getProperty("user.dir")
 + "\src\main\resources\Framework.xlsx");
 String testConfig = "select * from TestConfig where Browser='"
 + tempParam + "'";
 String allTestcases = "select * from TestCases";
  rs = conn.executeQuery(allTestcases);
 String strQuery2 = "select * from TestCases where TestCaseID='";
 rs = conn.executeQuery(testConfig);
 for (int i = 0; i < rs.getCount(); i++) {
 rs.next();
 System.out.println(rs.getField("Browser"));
 System.out.println(rs.getField("Execute_Flag"));
 if (rs.getField("Execute_Flag").equalsIgnoreCase("y")) {
 rs1 = conn.executeQuery(testcases
 + rs.getField("TestCaseID") + "'");

 System.out.println("Rs1 count: " + rs1.getCount());
 for (int j = 0; j < rs1.getCount(); j++) {
 rs1.next();
 tempMap = new HashMap<String, String>();
 tempMap.put("TestCaseID", rs1.getField("TestCaseID"));
 tempMap.put("TestStepID", rs1.getField("TestStepID"));
 tempMap.put("Object", rs1.getField("Object"));
 tempMap.put("Data", rs1.getField("Data"));
 tempMap.put("Keyword", rs1.getField("Keyword"));
 tempList.add((HashMap) tempMap);
 }
 }
 }
 objectArray = noRecords;
 objectArray = new Object[tempList.size()][5];
 for (int i = 0; i < tempList.size(); i++) {
 objectArray[i][0] = tempList.get(i).get("TestCaseID");
 objectArray[i][1] = tempList.get(i).get("TestStepID");
 objectArray[i][2] = tempList.get(i).get("Object");
 objectArray[i][3] = tempList.get(i).get("Data");
 objectArray[i][4] = tempList.get(i).get("Keyword");
 }
  } catch (FilloException e) {
 return noRecords;
 }
 String timestamp1 = new SimpleDateFormat("yyyyMMMddHHmmss")
 .format(new java.util.Date());
 System.out.println("Ending " + tempParam + timestamp1);
 return objectArray;
 }