public class IOSDriver<T extends WebElement>
    extends AppiumDriver<T>
    implements IOSDeviceActionShortcuts,
        FindsByIosUIAutomation<T> {
...

    @Override public TargetLocator switchTo() {
        return new InnerTargetLocator();
    }

    private class InnerTargetLocator extends RemoteTargetLocator {
        @Override public Alert alert() {
            return new IOSAlert(super.alert());
        }
    }

    class IOSAlert implements Alert {
        private final Alert alert;

        IOSAlert(Alert alert) {
            this.alert = alert;
        }

        @Override
        public void dismiss() {
            alert.dismiss();
        }

        @Override
        public void accept() {
            alert.accept();
        }

        @Override
        public String getText() {
            Response response = execute(DriverCommand.GET_ALERT_TEXT);
            return response.getValue().toString();
        }

        @Override
        public void sendKeys(String keysToSend) {
            execute(DriverCommand.SET_ALERT_VALUE, prepareArguments("value", keysToSend));
        }

        @Override
        public void setCredentials(Credentials credentials) {
            alert.setCredentials(credentials);
        }

        @Override
        public void authenticateUsing(Credentials credentials) {
            alert.authenticateUsing(credentials);
        }
    }
}