Android Room Use Nullable Variable for Embeded

One of the nice feature of Room is the ability to use an Embedded (store multiple fields as single class variable).

@Entity(tableName = "pin")class Pin (        @PrimaryKey        @ColumnInfo(name = "id") @Json(name = "id") var id: String = "",        // Must @Embedded be nullable?        // If somehow the underlying/saved value (@ColumnInfo) is null, loading/fetch will cause        // IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull        // https://developer.android.com/reference/android/arch/persistence/room/Embedded        // @NonNull doesn't work        @Embedded @Json(name = "geo") var location: LocationType? = null        ) {}

class LocationType(        @ColumnInfo(name = "lat") @Transient var lat: Double? = null,        @ColumnInfo(name = "lng") @Transient var lng: Double? = null) {    fun isNull(): Boolean {        return lat == null || lng == null || (lat == 0.0 && lng == 0.0)    }}

Original, I define LocationType as non nullable value to make checking of null or zero value easier.

@Embedded @Json(name = "geo") var location: LocationType? = null

if (!pin.location.isNull()) { // pin.location != null && !pin.location.isNull()    // do something}

Problem arise when the underlying database value of lat and lng is null, where LocationType cannot be initialized and set as null by the generated code, causing IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull.

I could probably write a converter to convert null to 0 when saving to database, but I doubt this is an good solution.

I decide to make LocationType nullable instead and assume 0,0 is a valid coordinate (and I won't stupidly convert null to 0 in some unknown cases).

if (pin.location != null) {  // do something}