org.hibernate.usertype
Interface UserType
- EnhancedUserType, UserVersionType
public interface UserType
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.
Object | assemble(Serializable cached, Object owner) - Reconstruct an object from the cacheable representation.
|
Object | deepCopy(Object value) - Return a deep copy of the persistent state, stopping at entities and at
collections.
|
Serializable | disassemble(Object value) - Transform the object into its cacheable representation.
|
boolean | equals(Object x, Object y) - Compare two instances of the class mapped by this type for persistence "equality".
|
int | hashCode(Object x) - Get a hashcode for the instance, consistent with persistence "equality"
|
boolean | isMutable() - Are objects of this type mutable?
|
Object | nullSafeGet(ResultSet rs, String[] names, Object owner) - Retrieve an instance of the mapped class from a JDBC resultset.
|
void | nullSafeSet(PreparedStatement st, Object value, int index) - Write an instance of the mapped class to a prepared statement.
|
Object | replace(Object original, Object target, 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 | returnedClass() - The class returned by nullSafeGet().
|
int[] | sqlTypes() - Return the SQL type codes for the columns mapped by this type.
|
assemble
public Object assemble(Serializable cached,
Object owner)
throws HibernateException
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)
cached
- the object to be cachedowner
- the owner of the cached object
- a reconstructed object from the cachable representation
deepCopy
public Object deepCopy(Object value)
throws HibernateException
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.
value
- the object to be cloned, which may be null
disassemble
public Serializable disassemble(Object value)
throws HibernateException
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)
value
- the object to be cached
- a cachable representation of the object
equals
public boolean equals(Object x,
Object y)
throws HibernateException
Compare two instances of the class mapped by this type for persistence "equality".
Equality of the persistent state.
hashCode
public int hashCode(Object x)
throws HibernateException
Get a hashcode for the instance, consistent with persistence "equality"
isMutable
public boolean isMutable()
Are objects of this type mutable?
nullSafeGet
public Object nullSafeGet(ResultSet rs,
String[] names,
Object owner)
throws HibernateException,
SQLException
Retrieve an instance of the mapped class from a JDBC resultset. Implementors
should handle possibility of null values.
rs
- a JDBC result setnames
- the column namesowner
- the containing entity
nullSafeSet
public void nullSafeSet(PreparedStatement st,
Object value,
int index)
throws HibernateException,
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.
st
- a JDBC prepared statementvalue
- the object to writeindex
- statement parameter index
replace
public Object replace(Object original,
Object target,
Object owner)
throws HibernateException
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.
original
- the value from the detached entity being mergedtarget
- the value in the managed entity
returnedClass
public Class returnedClass()
The class returned by nullSafeGet().
sqlTypes
public int[] sqlTypes()
Return the SQL type codes for the columns mapped by this type. The
codes are defined on java.sql.Types.