Tjyylli

This might look like a primitive question or a this could be done by a simple utility library method that I don't know about.

The goal is to check the value of a boolean field that is nested under two objects.

private boolean sourceWebsite(Registration registration) {

    Application application = registration.getApplication();

    if (application == null) {

        return true;

    }



    Metadata metadata = application.getMetadata();

    if (metadata == null) {

        return true;

    }



    Boolean source = metadata.getSource();

    if (source == null) {

        return true;

    }



    return !source;

}

I know this could be done in a single if(). I have added multiple ifs here for the sake of readability.

Is there a way that we could simplify the above if statements and have a simple utility class that returns the value of Boolean source if the parent objects or not null?

You can use java.util.Optional in this way:

private boolean sourceWebsite(Registration registration) {

    return Optional.of(registration)

        .map(Registration::getApplication)

        .map(Application::getMetadata)

        .map(Metadata::getSource)

        .map(source -> !source)

        .orElse(Boolean.TRUE);

}

In short, this will return true if any of the getters returns null, and !Metadata.source otherwise.

The following will return true if any one of is null. If all values are not null, it returns !source.

private boolean sourceWebsite(Registration registration) {

      return registration.getApplication() == null 

      ||     registration.getApplication().getMetadata() == null

      ||     registration.getApplication().getMetadata().getSource() == null

      ||    !registration.getApplication().getMetadata().getSource();



}

Updated :

If you want that every getter not called more than once then you can declare variable for every object like

private boolean sourceWebsite(Registration registration) {

      Application application;

      Metadata metadata;

      Source source;

      return (application = registration.getApplication()) == null 

      ||     (metadata = application.getMetadata()) == null

      ||     (source = metadata.getSource()) == null

      ||    !source;



 }

Another option you can use is a try-catch block. If you get a null pointer exception return true.

private boolean sourceWebsite(Registration registration) {

    try {

        return !registration.getApplication().getMetadata().getSource();

    }

    catch (NullPointerException e) {

        return true;

    }

}