What is the use of ElementLocatorFactory and FieldDecorator in Page Factory?

Question

Can someone please explain how to use ElementLocatorFactory and FieldDecorator in PageFactory using Selenium? I am unable to understand it and request you to explain this in layman terms.

Answer 1

When you use the PageFactory, the webelements instances are actually proxies and the elements have to be found before you call a method on them.

The getting part is encapsulated in the ElementLocator for each field. The ElementLocatorFactory provides these for each element. This factory needs a SearchContext provided to the factory constructor. The driver implements the SearchContext (the method findelement) or even a webelement. The By part that is how to look for them, is retrieved by reflection API on the fields of the pageobject.

Assigning the proxies to the fields is handled by the FieldDecorator, which requires the ElementLocatorFactory. The decorate() method called for each webelement field returns a proxy which is set for that field. When a method is called on the webelement it actually is called on the proxy. The proxy intercepts this call to use the SearchContext.findElement method to find the actual element and then calls your original method.

So one can create custom ElementLocatorFactory and FieldDecorator to pass to the PageFactory.

For a code-level explanation - http://www.alechenninger.com/2014/07/a-case-study-of-javas-dynamic-proxies_14.html.