Reusable generic base class DAOs with Android Room

Question

Is there any way to create reusable generic base class DAOs with Android Room?

public interface BaseDao {

  @Insert
  void insert(T object);

  @Up         


        

Answer 1

I have a solution for findAll.

Codes in that BaseDao:

...
public List findAll() {
    SimpleSQLiteQuery query = new SimpleSQLiteQuery(
        "select * from " + getTableName()
    );
    return doFindAll(query);
}
...
public String getTableName() {
    // Below is based on your inheritance chain
    Class clazz = (Class)
        ((ParameterizedType) getClass().getSuperclass().getGenericSuperclass())
            .getActualTypeArguments()[0];
    // tableName = StringUtil.toSnakeCase(clazz.getSimpleName());
    String tableName = clazz.getSimpleName();
    return tableName;
}
...
@RawQuery
protected abstract List doFindAll(SupportSQLiteQuery query);

and other Dao looks like :

@Dao
public abstract class UserDao extends AppDao {
}

That's all

The idea is

1. Get the table name of subclass's generic type on runtime
2. Pass that table name to a RawQuery

If you prefer interface to abstract class, you can try optional method of java 8.

It's not beautiful but worked, as you can see.

I created a gist at here