GetEntity methods | ScyllaDB Docs

GetEntity methods¶

Annotate a DAO method with @GetEntity to convert a core driver data structure into one or more Entities:

@Dao
public interface ProductDao {
  @GetEntity
  Product asProduct(Row row);
}

The generated code will retrieve each entity property from the source, such as:

Product product = new Product();
product.setId(row.get("id", UUID.class));
product.setDescription(row.get("description", String.class));
...

It does not perform a query. Instead, those methods are intended for cases where you already have a query result, and just need the conversion logic.

Parameters¶

The method must have a single parameter. The following types are allowed:

GettableByName or one of its subtypes (the most likely candidates are Row and UdtValue).
ResultSet.
AsyncResultSet.

The data must match the target entity: the generated code will try to extract every mapped property, and fail if one is missing.

Return type¶

The method can return:

a single entity instance. If the argument is a result set type, the generated code will extract the first row and convert it, or return null if the result set is empty.
```
@GetEntity
Product asProduct(Row row);

@GetEntity
Product firstRowAsProduct(ResultSet resultSet);
```
```
a PagingIterable of an entity class. In that case, the type of the parameter must be ResultSet. Each row in the result set will be converted into an entity instance.
```
@GetEntity
PagingIterable<Product> asProducts(ResultSet resultSet);
```
a MappedAsyncPagingIterable of an entity class. In that case, the type of the parameter must be AsyncResultSet. Each row in the result set will be converted into an entity instance.
```
@GetEntity
MappedAsyncPagingIterable<Product> asProducts(AsyncResultSet resultSet);
```

If the return type doesn’t match the parameter type (for example PagingIterable for AsyncResultSet), the mapper processor will issue a compile-time error.

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ScyllaDB Java Driver is available under the Apache v2 License. ScyllaDB Java Driver is a fork of DataStax Java Driver. See Copyright here.