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

Enum NullSavingStrategy

java.lang.Object

java.lang.Enum<NullSavingStrategy>

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

All Implemented Interfaces:

Serializable, Comparable<NullSavingStrategy>

public enum NullSavingStrategy
extends Enum<NullSavingStrategy>

Defines how null Entity properties will be handled during data insertion.

Enum Constant Summary

Enum Constants

Enum Constant and Description
DO_NOT_SET Do not insert null properties.
SET_TO_NULL Insert null properties as a CQL NULL.

Method Summary

Modifier and Type	Method and Description
static NullSavingStrategy	valueOf(String name) Returns the enum constant of this type with the specified name.
static NullSavingStrategy[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

DO_NOT_SET

public static final NullSavingStrategy DO_NOT_SET

Do not insert null properties.

In other words, the mapper won't call the corresponding setter on the BoundStatement. The generated code looks approximately like this:

 if (entity.getDescription() != null) {
   boundStatement = boundStatement.setString("description", entity.getDescription());
 }
 

This avoids inserting tombstones for null properties. On the other hand, if the query is an update and the column previously had another value, it won't be overwritten.

Note that unset values are only supported with native protocol v4 (Cassandra 2.2) or above. If you try to use this strategy with a lower Cassandra version, the mapper will throw a MapperException when you try to build the corresponding DAO.

See Also:

CASSANDRA-7304

SET_TO_NULL

public static final NullSavingStrategy SET_TO_NULL

Insert null properties as a CQL NULL.

In other words, the mapper will always call the corresponding setter on the BoundStatement. The generated code looks approximately like this:

 // Called even if entity.getDescription() == null
 boundStatement = boundStatement.setString("description", entity.getDescription());
 

Method Detail

values

public static NullSavingStrategy[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (NullSavingStrategy c : NullSavingStrategy.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static NullSavingStrategy valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null