Package org.hibernate.usertype

Interface UserType<J>

All Known Subinterfaces:

EnhancedUserType<J>, UserVersionType<T>

All Known Implementing Classes:

BaseUserTypeSupport, EnumType, RevisionTypeType, StaticUserTypeSupport, UserTypeLegacyBridge, UserTypeSupport

public interface UserType<J>

This interface should be implemented by user-defined "types". A "type" class is not the actual property type - it is a class that knows how to serialize instances of another class to and from JDBC.

This interface

• abstracts user code from future changes to the Type interface,
• simplifies the implementation of custom types and
• hides certain "internal" interfaces from user code.

Implementors must be immutable and must declare a public default constructor.

The actual class mapped by a UserType may be just about anything.

CompositeUserType provides an extended version of this interface that is useful for more complex cases.

Alternatively, custom types could implement Type directly or extend one of the abstract classes in org.hibernate.type. This approach risks future incompatible changes to classes or interfaces in that package.

See Also:

Type, CustomType

Method Summary

Modifier and Type	Method	Description
J	assemble(Serializable cached, Object owner)	Reconstruct an object from the cacheable representation.
J	deepCopy(J value)	Return a deep copy of the persistent state, stopping at entities and at collections.
Serializable	disassemble(J value)	Transform the object into its cacheable representation.
boolean	equals(J x, J y)	Compare two instances of the class mapped by this type for persistence "equality".
default long	getDefaultSqlLength(Dialect dialect, JdbcType jdbcType)
default int	getDefaultSqlPrecision(Dialect dialect, JdbcType jdbcType)
default int	getDefaultSqlScale(Dialect dialect, JdbcType jdbcType)
default JdbcType	getJdbcType(TypeConfiguration typeConfiguration)
int	getSqlType()	Return the SQL type code for the column mapped by this type.
default BasicValueConverter<J,Object>	getValueConverter()	Returns the converter that this user type uses for transforming from the domain type, to the relational type, or null if there is no conversion.
int	hashCode(J x)	Get a hashcode for the instance, consistent with persistence "equality"
boolean	isMutable()	Are objects of this type mutable?
J	nullSafeGet(ResultSet rs, int position, SharedSessionContractImplementor session, Object owner)	Retrieve an instance of the mapped class from a JDBC resultset.
void	nullSafeSet(PreparedStatement st, J value, int index, SharedSessionContractImplementor session)	Write an instance of the mapped class to a prepared statement.
J	replace(J detached, J managed, Object owner)	During merge, replace the existing (target) value in the entity we are merging to with a new (original) value from the detached entity we are merging.
Class<J>	returnedClass()	The class returned by nullSafeGet().

Method Detail

getSqlType

int getSqlType()

Return the SQL type code for the column mapped by this type. The codes are generally defined on org.hibernate.type.SqlTypes, but could be database-specific codes

See Also:

SqlTypes

returnedClass

Class<J> returnedClass()

The class returned by nullSafeGet().

Returns:

Class

equals

boolean equals(J x,
               J y)

Compare two instances of the class mapped by this type for persistence "equality". Equality of the persistent state.

hashCode

int hashCode(J x)

Get a hashcode for the instance, consistent with persistence "equality"

nullSafeGet

J nullSafeGet(ResultSet rs,
              int position,
              SharedSessionContractImplementor session,
              Object owner)
       throws SQLException

Retrieve an instance of the mapped class from a JDBC resultset. Implementors should handle possibility of null values.

Throws:

SQLException

nullSafeSet

void nullSafeSet(PreparedStatement st,
                 J value,
                 int index,
                 SharedSessionContractImplementor session)
          throws SQLException

Write an instance of the mapped class to a prepared statement. Implementors should handle possibility of null values. A multi-column type should be written to parameters starting from index.

Throws:

SQLException

deepCopy

J deepCopy(J value)

Return a deep copy of the persistent state, stopping at entities and at collections. It is not necessary to copy immutable objects, or null values, in which case it is safe to simply return the argument.

Parameters:

value - the object to be cloned, which may be null

Returns:

Object a copy

isMutable

boolean isMutable()

Are objects of this type mutable?

Returns:

boolean

disassemble

Serializable disassemble(J value)

Transform the object into its cacheable representation. At the very least this method should perform a deep copy if the type is mutable. That may not be enough for some implementations, however; for example, associations must be cached as identifier values. (optional operation)

Parameters:

value - the object to be cached

Returns:

a cacheable representation of the object

assemble

J assemble(Serializable cached,
           Object owner)

Reconstruct an object from the cacheable representation. At the very least this method should perform a deep copy if the type is mutable. (optional operation)

Parameters:

cached - the object to be cached

owner - the owner of the cached object

Returns:

a reconstructed object from the cacheable representation

replace

J replace(J detached,
          J managed,
          Object owner)

During merge, replace the existing (target) value in the entity we are merging to with a new (original) value from the detached entity we are merging. For immutable objects, or null values, it is safe to simply return the first parameter. For mutable objects, it is safe to return a copy of the first parameter. For objects with component values, it might make sense to recursively replace component values.

Parameters:

detached - the value from the detached entity being merged

managed - the value in the managed entity

Returns:

the value to be merged

getDefaultSqlLength

default long getDefaultSqlLength(Dialect dialect,
                                 JdbcType jdbcType)

getDefaultSqlPrecision

default int getDefaultSqlPrecision(Dialect dialect,
                                   JdbcType jdbcType)

getDefaultSqlScale

default int getDefaultSqlScale(Dialect dialect,
                               JdbcType jdbcType)

getJdbcType

default JdbcType getJdbcType(TypeConfiguration typeConfiguration)

getValueConverter

default BasicValueConverter<J,Object> getValueConverter()

Returns the converter that this user type uses for transforming from the domain type, to the relational type, or null if there is no conversion. Note that it is vital to provide a converter if a column should be mapped to multiple domain types, as Hibernate will only select a column once and materialize values as JdbcMapping.getJdbcJavaType(). Support for multiple domain type representations works by converting objects of that type to the domain type.