public class ExprWindow extends SimpleExpression<WebDriver>{
    private Expression<WebDriver> driver;
    @Override
    public Class<? extends WebDriver> getReturnType() {
        // TODO Auto-generated method stub
        return WebDriver.class;
    }

    @Override
    public boolean isSingle() {
        // TODO Auto-generated method stub
        return true;
    }

    @Override
    public boolean init(Expression<?>[] expr, int matchedPattern, Kleenean paramKleenean, ParseResult paramParseResult) {
        // TODO Auto-generated method stub
        driver = (Expression<WebDriver>) expr[0];
        return true;
    }

    @Override
    public String toString(@Nullable Event e, boolean arg1) {
        // TODO Auto-generated method stub
        return "Window";
    }

    @Override
    @Nullable
    protected WebDriver[] get(Event e) {
        // TODO Auto-generated method stub
        return new WebDriver[]{driver};
    }

}