...
public abstract class MobileBy extends By implements Serializable {
    private final String automatorText;

    public MobileBy(String automatorText) {
        this.automatorText = automatorText;
    }

    protected String getAutomatorText() {
        return automatorText;
    }

    ...

    public static class ByIosUIAutomation extends MobileBy  {
        public ByIosUIAutomation(String uiautomationText) {
            super(uiautomationText);
        }

        @SuppressWarnings("unchecked")
        @Override
        public List<WebElement> findElements(SearchContext context) {
            return (List<WebElement>) ((FindsByIosUIAutomation<?>) context)
                    .findElementsByIosUIAutomation(getAutomatorText());
        }

        @Override public WebElement findElement(SearchContext context) {
            return ((FindsByIosUIAutomation<?>) context)
                .findElementByIosUIAutomation(getAutomatorText());
        } 

        @Override public String toString() {
            return "By.IosUIAutomation: " + getAutomatorText();
        } 
    }

    public static class ByAndroidUIAutomator extends MobileBy {
        public ByAndroidUIAutomator(String uiautomatorText) {
            super(uiautomationText);
        }

        @SuppressWarnings("unchecked")
        @Override
        public List<WebElement> findElements(SearchContext context) {
            return (List<WebElement>) ((FindsByAndroidUIAutomator<?>) context)
                    .findElementsByAndroidUIAutomator(getAutomatorText());
        }

        @Override public WebElement findElement(SearchContext context) {
            return ((FindsByAndroidUIAutomator<?>) context)
                .findElementByAndroidUIAutomator(getAutomatorText());
        }

        @Override public String toString() {
            return "By.AndroidUIAutomator: " + automatorText;
        }

        @Override public String getAutomatorText() {
            return automatorText;
        }
    }

    public static class ByAccessibilityId extends By implements Serializable {

        private final String id;

        public ByAccessibilityId(String id) {
            this.id = id;
        }

        @SuppressWarnings("unchecked")
        @Override
        public List<WebElement> findElements(SearchContext context) {
            return (List<WebElement>) ((FindsByAccessibilityId<?>) context)
                .findElementsByAccessibilityId(id);
        }

        @Override public WebElement findElement(SearchContext context) {
            return ((FindsByAccessibilityId<?>) context).findElementByAccessibilityId(id);
        }

        @Override public String toString() {
            return "By.AccessibilityId: " + id;
        }
    }
}

 public class AndroidDriver<T extends WebElement>
    extends AppiumDriver<T>
    implements AndroidDeviceActionShortcuts, HasNetworkConnection, PushesFiles, StartsActivity,
    FindsByAndroidUIAutomator<T> {

    ....
    @Override public T scrollTo(String text) {
        String uiScrollables =
            uiScrollable("new UiSelector().descriptionContains(\"" + text + "\")") 
                + uiScrollable("new UiSelector().textContains(\"" + text + "\")");
        return findElementByAndroidUIAutomator(uiScrollables);
    }

    @Override public T scrollToExact(String text) {
        String uiScrollables =
            uiScrollable("new UiSelector().description(\"" + text + "\")") + uiScrollable(
                "new UiSelector().text(\"" + text + "\")");
        return findElementByAndroidUIAutomator(uiScrollables);
    }

    public T scrollToUsingAutomamator(ByAndroidUIAutomator by) {
        return findElementByAndroidUIAutomator(uiScrollable(by.getAutomatorText()));
    }   
    ....
}

public class IOSDriver<T extends WebElement>
    extends AppiumDriver<T>
    implements IOSDeviceActionShortcuts, GetsNamedTextField<T>,
    FindsByIosUIAutomation<T> {
    ....
    @SuppressWarnings("unchecked")
    @Override
    public T scrollTo(String text) {
        return (T) ((ScrollsTo<?>) findElementByClassName("UIATableView"))
            .scrollTo(text);
    }

    @SuppressWarnings("unchecked")
    @Override
    public T scrollToExact(String text) {
        return (T) ((ScrollsTo<?>) findElementByClassName("UIATableView"))
            .scrollToExact(text);
    }

   public T scrollToUsingPredicate(By scrollableElementBy, String iOSpredicate) {
        return (T) findElementBy(scrollableElementBy)
            .scrollToUsingPredicate(iOSpredicate);
   }

   public T scrollToUsingPredicate(String iOSpredicate) {
        return scrollToUsingPredicate(By.className("UIATableView"), iOSpredicate);
   }
    ....
}

public class IOSElement extends MobileElement
    implements FindsByIosUIAutomation<MobileElement>, ScrollsTo<MobileElement> {
    ....
    public MobileElement scrollToUsingPredicate(String iOSpredicate) {
        return (IOSElement) findElementByIosUIAutomation(
            ".scrollToElementWithPredicate(\"" + iOSpredicate + ""\")");
    }

    @Override public MobileElement scrollTo(String text) {
        return scrollToUsingPredicate("name CONTAINS '" + text + "'");
    }

    @Override public MobileElement scrollToExact(String text) {
        return scrollToUsingPredicate("name == '" + text + "'");
    }
    ....
}