How to save inherited class using astyanax?

Question

I am unable to save child class data with the persistence of parent class using astyanax in cassandra.

I created the child object with all necessary data, but when I try to store that object, only values from the parent class is stored, not from child object.

Here is the sample Code not real:

@Entity
class Shape{
    @Id
    private String id;
    @Column
    private String name;
}

@Entity
class square extends Shape{

    @column
    private int width;
}

now to store I am using EntityManager of  astyanax.

square s=new square();
s.setName("sqaure");
s.setWidth(100);
s.setId("1234");
EntityManager em= //initialization code
em.put(s);

after doing this only "name" and "id" is stored into database. not width.

Answer 1

The EntityManager requires the type of the entity via the withEntityType() method. This type is used to build an EntityMapper via reflection which then determines the fields to serialize. There is nothing in the Entity persistence documentation or examples that says Astyanax supports polymorphism. This is not a bug, just a feature that doesn't exist. You will need a type-specific EntityManager for each subtype of your base class.