com.datastax.oss.driver.api.mapper.annotations

Annotation Type SetEntity

@Target(value=METHOD)
 @Retention(value=RUNTIME)
public @interface SetEntity

Annotates a Dao method that fills a core driver data structure from an instance of an Entity class.

Example:

 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.

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.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
boolean	lenient Whether to tolerate missing columns in the target data structure.
NullSavingStrategy	nullSavingStrategy How to handle null entity properties.

Element Detail

nullSavingStrategy

public abstract NullSavingStrategy nullSavingStrategy

How to handle null entity properties.

This defaults either to the DAO-level strategy (if set), or NullSavingStrategy.DO_NOT_SET.

Default:

com.datastax.oss.driver.api.mapper.entity.saving.NullSavingStrategy.DO_NOT_SET

lenient

public abstract boolean lenient

Whether to tolerate missing columns in the target data structure.

If false (the default), then the target must contain a matching column for every property in the entity definition, except computed ones. If such a column is not found, an IllegalArgumentException will be thrown.

If true, the mapper will operate on a best-effort basis and attempt to write all entity properties that have a matching column in the target, leaving unmatched properties untouched. Beware that this may result in a partially-populated target.

Default:

false