DecimalUtil for Android Data Binding Library

1. activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
    <data>
        <import type="java.math.BigDecimal"></import>
        <import type="com.arit.demo.mvvm.DecimalUtil"></import>
        <import type="android.view.View"></import>
        <variable name="qty" type="int"></variable>
        <variable name="user" type="com.arit.demo.mvvm.User"></variable>
        <variable name="handler" type="com.arit.demo.mvvm.ClickHandler"></variable>
    </data>
    <android.support.constraint.ConstraintLayout
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
        <EditText
            android:id="@+id/editText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ems="10"
            android:inputType="textPersonName"
            android:text="@={DecimalUtil.convertToString(user.age)}"
            app:layout_constraintBottom_toTopOf="@+id/tvFirstname"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            android:layout_marginBottom="20dp"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@{DecimalUtil.convertToString(user.age), default = `18`}"
            android:visibility="@{(user.age.intValue() > 20) ? View.VISIBLE : View.GONE }"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            android:textSize="30sp"
            android:id="@+id/tvFirstname"/>

        <Button
            android:id="@+id/btnDoEvent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Normal Click"
            android:onClick="@{()-> handler.onButtonClick(user)}"/>

        <Button
            android:id="@+id/btnDoEventByLambda"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Lambda Click" />


    </android.support.constraint.ConstraintLayout>
</layout>

2. DecimalUtil
public class DecimalUtil {

    @InverseMethod("convertToString")
    public static BigDecimal stringToDecimal(String value){
        if(!value.isEmpty()) {
            return new BigDecimal(value);
        }else{
            return BigDecimal.valueOf(0);
        }
    }
    public static String convertToString(BigDecimal value){
        DecimalFormat formater = new DecimalFormat("#,###,###.00");
        return String.valueOf(formater.format(value));
    }
}