How to convert string to By type

Question

How to convert String to By type.

Following is my scenario: Keep object identification in Properties file in below manner

username=By.id(\"username\")
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Answer 1

You have to evaluate the entire expression within the context of existing code. You should framework such as JEXL or expressionoasis

Code below uses JEXL

// Create JexlEngine instance
JexlEngine jexl = new JexlEngine();
// Create Expression object for the string
Expression e = jexl.createExpression(prop.getProperty("username"));

// Create a context. You can pass reference to any object you want to use inside the expression
JexlContext jc = new MapContext();

// Now evaluate the expression, getting the result
driver.findElement((By)e.evaluate(jc)); 

Answer 2

The WebDriver.findElement method accepts only an object parameter of the type By. The Property.getProperty method returns only a String typed object.

Therefore, this may be what fits your need:

WebElement element = driver.findElement(By.name(prop.getProperty("username")));

You can't force a String typed object into a method that accepts only a By typed object. When you ask Selenium to find a String "username" you have to tell it more than just the string's value.

The method By.[method] you choose all depends on what you are looking for in the page that Selenium is searching. "username" is most likely the "name" (By.name) or "id" (By.Id) of the field you are looking for. The By class refines the search to where you expect the String "username" to be: in a name, id, tag, class, etc. See the By class definition.

Also, take caution as the getProperty method could return a null, and the By methods with throw an IllegalArgumentException if you pass it a null string. So providing a default return value ("") for getProperty is usually safer.

WebElement element = driver.findElement(By.name(prop.getProperty("username", "")));

Answer 3

I think you are trying to implement page object model using properties file. What I would suggest here to use xml file instead of java properties file. for example sample xml for page elements would look like below.

<Pages>
<LoginPage>
    <txtUserName by="id">username</txtUserName>
    <txtPassword by="id">password</txtPassword>
</LoginPage>
</Pages>

Now you can write methods retrieve nodes from the xml file and node attribute as id,xpath etc... further write methods to find elements using xml node value and attribute. I have used same method in my project as it works great for me.

Answer 4

You can create one parser method which will return desired locator object something like below:

public static By locatorParser(String locator) {

By loc = By.id(locator);

if (locator.contains("id"))
    loc = By.id(locator.substring(locator.indexOf("\"") + 1,
        locator.length() - 2));

else if (locator.contains("name"))
    loc = By.name(locator.substring(locator.indexOf("\"") + 1,
        locator.length() - 2));

if (locator.contains("xpath"))
    loc = By.xpath(locator.substring(locator.indexOf("\"") + 1,
        locator.length() - 2));

return loc;

}

Can be called in your code in the following way:

driver.findElement(locatorParser(prop.getProperty("username")));

Added logic for id, name, xpath. You can modify the same method to add all the available locators. Hope this helps!