AutoValueGson + SQLDelight

Extends from my previous post Retrofit 2 + AutoValueGson, I’m trying to add a database for the project. I choose to use ContentProvider due to the benefit of ContentObserver, with the help of SQLDelight to generate all the necessary fields in Java model.

I first create an User.sq file under src/main/sqldelight/{package}/User.sq, it will generated as UserModel.java interface file under {package} package.

CREATE TABLE IF NOT EXISTS user (
    _id INTEGER PRIMARY KEY AUTOINCREMENT,
    login TEXT NOT NULL,
    id INTEGER NOT NULL,
    avatarUrl TEXT,
    UNIQUE (login) ON CONFLICT REPLACE
);

drop_table:
DROP TABLE IF EXISTS user;

selectAll:
SELECT *
FROM user;

insertRow:
INSERT INTO user(login, id, avatarUrl)
VALUES (?, ?, ?);

Then I rename UserBean.

@AutoValue
public abstract class UserBean {
    public abstract String login();

    public abstract int id();

    @Nullable
    public abstract String avatarUrl();

    public static UserModel create(String login, int id, @Nullable String avatarUrl) {
        return new AutoValue_UserModel(login, id, avatarUrl);
    }

    public static TypeAdapter<UserModel> typeAdapter(Gson gson) {
        return new AutoValue_UserModel.GsonTypeAdapter(gson);
    }
}

Change it to User implements UserModel.

@AutoValue
public abstract class User implements UserModel {
    public static final Factory<User> FACTORY = new Factory<>(
            (_id, login, id, avatarUrl) -> new AutoValue_User(null, login, id, avatarUrl));
    public static final RowMapper<User> SELECT_ALL_MAPPER = FACTORY.selectAllMapper();

    public static TypeAdapter<User> typeAdapter(Gson gson) {
        return new AutoValue_User.GsonTypeAdapter(gson);
    }

    public ContentValues asContentValues() {
        return new Marshal(this).asContentValues();
    }
}

In order to create or drop a table, it can simply call to User.CREATE_TABLE or User.DROP_TABLE.

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "app.db";
    private static final int DATABASE_VERSION = 1;

    private static DatabaseHelper instance;

    public static DatabaseHelper getInstance(Context context) {
        if (instance == null) {
            instance = new DatabaseHelper(context.getApplicationContext());
        }
        return instance;
    }

    private DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(User.CREATE_TABLE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL(User.DROP_TABLE);
        onCreate(db);
    }
}

For select record from a table, it can use UserModel.Mapper#map(Cursor) to convert an Cursor to User.

For insert record into a table, it can use UserModel.Marshal#asContentValues() to convert an User to ContentValues.

public class SqlBriteHelper {
    private final ContentResolver contentResolver;
    private final BriteContentResolver briteResolver;

    @Inject
    public SqlBriteHelper(ContentResolver contentResolver) {
        this.contentResolver = contentResolver;
        this.briteResolver = new SqlBrite.Builder()
                .build()
                .wrapContentProvider(contentResolver, Schedulers.io());
    }

    public Observable<List<User>> getUserList() {
        return briteResolver.createQuery(User.CONTENT_URI, null, null, null, null, false)
                .mapToList(User.SELECT_ALL_MAPPER::map);
    }

    public Observable<List<User>> setUserList(List<User> userList) {
        return Observable.defer(() -> {
            for (User user : userList) {
                contentResolver.insert(User.CONTENT_URI, user.asContentValues());
            }
            return Observable.just(userList);
        });
    }
}

The full project can be found at GitHub.