SetEntity methods | Scylla Docs

SetEntity methods¶

Annotate a DAO method with @SetEntity to fill a core driver data structure from an Entity:

public interface ProductDao {
  @SetEntity
  BoundStatement bind(Product product, BoundStatement boundStatement);
}

The generated code will set each entity property on the target, such as:

boundStatement = boundStatement.set("id", product.getId(), UUID.class);
boundStatement = boundStatement.set("description", product.getDescription(), String.class);
...

It does not perform a query. Instead, those methods are intended for cases where you will execute the query yourself, and just need the conversion logic.

Parameters¶

The method must have two parameters: one is the entity instance, the other must be a subtype of SettableByName (the most likely candidates are BoundStatement, BoundStatementBuilder and UdtValue). Note that you can’t use SettableByName itself.

The order of the parameters does not matter.

The annotation can define a null saving strategy that applies to the properties of the object to set. This is only really useful with bound statements (or bound statement builders): if the target is a UdtValue, the driver sends null fields in the serialized form anyway, so both strategies are equivalent.

Return type¶

The method can either be void, or return the exact same type as its settable parameter.

@SetEntity
void bind(Product product, UdtValue udtValue);

@SetEntity
void bind(Product product, BoundStatementBuilder builder);

Note that if the settable parameter is immutable, the method should return a new instance, because the generated code won’t be able to modify the argument in place. This is the case for BoundStatement, which is immutable in the driver:

// Wrong: statement won't be modified
@SetEntity
void bind(Product product, BoundStatement statement);

// Do this instead:
@SetEntity
BoundStatement bind(Product product, BoundStatement statement);

If you use a void method with BoundStatement, the mapper processor will issue a compile-time warning.