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Type (Hibernate API Documentation) - Hibernate 3.2.3 正式版 API 英文文档


org.hibernate.type
Interface Type

All Superinterfaces:
Serializable
All Known Subinterfaces:
AbstractComponentType, AssociationType, DiscriminatorType, IdentifierType, VersionType
All Known Implementing Classes:
AbstractBynaryType, AbstractType, AnyType, BigIntegerType, BooleanType, ByteType, CalendarType, CharacterType, CollectionType, ComponentType, CompositeCustomType, CustomType, DateType, DbTimestampType, EntityType, IntegerType, LongType, ShortType, StringType, TimestampType

public interface Type
extends Serializable

Defines a mapping from a Java type to an JDBC datatype. This interface is intended to be implemented by applications that need custom types.

Implementors should usually be immutable and must certainly be threadsafe.

Author:
Gavin King

Method Summary
 Object assemble(Serializable cached, SessionImplementor session, Object owner)
          Reconstruct the object from its cached "disassembled" state.
 void beforeAssemble(Serializable cached, SessionImplementor session)
          Called before assembling a query result set from the query cache, to allow batch fetching of entities missing from the second-level cache.
 int compare(Object x, Object y, EntityMode entityMode)
          compare two instances of the type
 Object deepCopy(Object value, EntityMode entityMode, SessionFactoryImplementor factory)
          Return a deep copy of the persistent state, stopping at entities and at collections.
 Serializable disassemble(Object value, SessionImplementor session, Object owner)
          Return a cacheable "disassembled" representation of the object.
 Object fromXMLNode(org.dom4j.Node xml, Mapping factory)
          Parse the XML representation of an instance.
 int getColumnSpan(Mapping mapping)
          How many columns are used to persist this type.
 int getHashCode(Object x, EntityMode entityMode)
          Get a hashcode, consistent with persistence "equality"
 int getHashCode(Object x, EntityMode entityMode, SessionFactoryImplementor factory)
          Get a hashcode, consistent with persistence "equality"
 String getName()
          Returns the abbreviated name of the type.
 Class getReturnedClass()
          The class returned by nullSafeGet() methods.
 Type getSemiResolvedType(SessionFactoryImplementor factory)
          Get the type of a semi-resolved value.
 Object hydrate(ResultSet rs, String[] names, SessionImplementor session, Object owner)
          Retrieve an instance of the mapped class, or the identifier of an entity or collection, from a JDBC resultset.
 boolean isAnyType()
          Is this an "any" type.
 boolean isAssociationType()
          Return true if the implementation is castable to AssociationType.
 boolean isCollectionType()
          Is this type a collection type.
 boolean isComponentType()
          Is this type a component type.
 boolean isDirty(Object old, Object current, boolean[] checkable, SessionImplementor session)
          Should the parent be considered dirty, given both the old and current field or element value?
 boolean isDirty(Object old, Object current, SessionImplementor session)
          Should the parent be considered dirty, given both the old and current field or element value?
 boolean isEntityType()
          Is this type an entity type?
 boolean isEqual(Object x, Object y, EntityMode entityMode)
          Compare two instances of the class mapped by this type for persistence "equality" - equality of persistent state.
 boolean isEqual(Object x, Object y, EntityMode entityMode, SessionFactoryImplementor factory)
          Compare two instances of the class mapped by this type for persistence "equality" - equality of persistent state.
 boolean isModified(Object oldHydratedState, Object currentState, boolean[] checkable, SessionImplementor session)
          Has the parent object been modified, compared to the current database state?
 boolean isMutable()
          Are objects of this type mutable.
 boolean isSame(Object x, Object y, EntityMode entityMode)
          Compare two instances of the class mapped by this type for persistence "equality" - equality of persistent state - taking a shortcut for entity references.
 boolean isXMLElement()
           
 Object nullSafeGet(ResultSet rs, String[] names, SessionImplementor session, Object owner)
          Retrieve an instance of the mapped class from a JDBC resultset.
 Object nullSafeGet(ResultSet rs, String name, SessionImplementor session, Object owner)
          Retrieve an instance of the mapped class from a JDBC resultset.
 void nullSafeSet(PreparedStatement st, Object value, int index, boolean[] settable, SessionImplementor session)
          Write an instance of the mapped class to a prepared statement, ignoring some columns.
 void nullSafeSet(PreparedStatement st, Object value, int index, SessionImplementor session)
          Write an instance of the mapped class to a prepared statement.
 Object replace(Object original, Object target, SessionImplementor session, Object owner, Map copyCache)
          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.
 Object replace(Object original, Object target, SessionImplementor session, Object owner, Map copyCache, ForeignKeyDirection foreignKeyDirection)
          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.
 Object resolve(Object value, SessionImplementor session, Object owner)
          Map identifiers to entities or collections.
 Object semiResolve(Object value, SessionImplementor session, Object owner)
          Given a hydrated, but unresolved value, return a value that may be used to reconstruct property-ref associations.
 void setToXMLNode(org.dom4j.Node node, Object value, SessionFactoryImplementor factory)
          A representation of the value to be embedded in an XML element.
 int[] sqlTypes(Mapping mapping)
          Return the SQL type codes for the columns mapped by this type.
 boolean[] toColumnNullness(Object value, Mapping mapping)
          Given an instance of the type, return an array of boolean, indicating which mapped columns would be null.
 String toLoggableString(Object value, SessionFactoryImplementor factory)
          A representation of the value to be embedded in a log file.
 

Method Detail

isAssociationType

public boolean isAssociationType()
Return true if the implementation is castable to AssociationType. This does not necessarily imply that the type actually represents an association.

Returns:
boolean
See Also:
AssociationType

isCollectionType

public boolean isCollectionType()
Is this type a collection type.


isComponentType

public boolean isComponentType()
Is this type a component type. If so, the implementation must be castable to AbstractComponentType. A component type may own collections or associations and hence must provide certain extra functionality.

Returns:
boolean
See Also:
AbstractComponentType

isEntityType

public boolean isEntityType()
Is this type an entity type?

Returns:
boolean

isAnyType

public boolean isAnyType()
Is this an "any" type. i.e. a reference to a persistent entity that is not modelled as a (foreign key) association.


isXMLElement

public boolean isXMLElement()

sqlTypes

public int[] sqlTypes(Mapping mapping)
               throws MappingException
Return the SQL type codes for the columns mapped by this type. The codes are defined on java.sql.Types.

Returns:
the typecodes
Throws:
MappingException
See Also:
Types

getColumnSpan

public int getColumnSpan(Mapping mapping)
                  throws MappingException
How many columns are used to persist this type.

Throws:
MappingException

getReturnedClass

public Class getReturnedClass()
The class returned by nullSafeGet() methods. This is used to establish the class of an array of this type.

Returns:
Class

isSame

public boolean isSame(Object x,
                      Object y,
                      EntityMode entityMode)
               throws HibernateException
Compare two instances of the class mapped by this type for persistence "equality" - equality of persistent state - taking a shortcut for entity references.

Parameters:
x -
y -
entityMode -
Returns:
boolean
Throws:
HibernateException

isEqual

public boolean isEqual(Object x,
                       Object y,
                       EntityMode entityMode)
                throws HibernateException
Compare two instances of the class mapped by this type for persistence "equality" - equality of persistent state.

Parameters:
x -
y -
entityMode -
Returns:
boolean
Throws:
HibernateException

isEqual

public boolean isEqual(Object x,
                       Object y,
                       EntityMode entityMode,
                       SessionFactoryImplementor factory)
                throws HibernateException
Compare two instances of the class mapped by this type for persistence "equality" - equality of persistent state.

Parameters:
x -
y -
entityMode -
Returns:
boolean
Throws:
HibernateException

getHashCode

public int getHashCode(Object x,
                       EntityMode entityMode)
                throws HibernateException
Get a hashcode, consistent with persistence "equality"

Parameters:
x -
entityMode -
Throws:
HibernateException

getHashCode

public int getHashCode(Object x,
                       EntityMode entityMode,
                       SessionFactoryImplementor factory)
                throws HibernateException
Get a hashcode, consistent with persistence "equality"

Parameters:
x -
entityMode -
factory -
Throws:
HibernateException

compare

public int compare(Object x,
                   Object y,
                   EntityMode entityMode)
compare two instances of the type

Parameters:
entityMode -

isDirty

public boolean isDirty(Object old,
                       Object current,
                       SessionImplementor session)
                throws HibernateException
Should the parent be considered dirty, given both the old and current field or element value?

Parameters:
old - the old value
current - the current value
session -
Returns:
true if the field is dirty
Throws:
HibernateException

isDirty

public boolean isDirty(Object old,
                       Object current,
                       boolean[] checkable,
                       SessionImplementor session)
                throws HibernateException
Should the parent be considered dirty, given both the old and current field or element value?

Parameters:
old - the old value
current - the current value
checkable - which columns are actually updatable
session -
Returns:
true if the field is dirty
Throws:
HibernateException

isModified

public boolean isModified(Object oldHydratedState,
                          Object currentState,
                          boolean[] checkable,
                          SessionImplementor session)
                   throws HibernateException
Has the parent object been modified, compared to the current database state?

Parameters:
oldHydratedState - the database state, in a "hydrated" form, with identifiers unresolved
currentState - the current state of the object
checkable - which columns are actually updatable
session -
Returns:
true if the field has been modified
Throws:
HibernateException

nullSafeGet

public Object nullSafeGet(ResultSet rs,
                          String[] names,
                          SessionImplementor session,
                          Object owner)
                   throws HibernateException,
                          SQLException
Retrieve an instance of the mapped class from a JDBC resultset. Implementors should handle possibility of null values.

Parameters:
rs -
names - the column names
session -
owner - the parent entity
Returns:
Object
Throws:
HibernateException
SQLException
See Also:
alternative, 2-phase property initialization

nullSafeGet

public Object nullSafeGet(ResultSet rs,
                          String name,
                          SessionImplementor session,
                          Object owner)
                   throws HibernateException,
                          SQLException
Retrieve an instance of the mapped class from a JDBC resultset. Implementations should handle possibility of null values. This method might be called if the type is known to be a single-column type.

Parameters:
rs -
name - the column name
session -
owner - the parent entity
Returns:
Object
Throws:
HibernateException
SQLException

nullSafeSet

public void nullSafeSet(PreparedStatement st,
                        Object value,
                        int index,
                        boolean[] settable,
                        SessionImplementor session)
                 throws HibernateException,
                        SQLException
Write an instance of the mapped class to a prepared statement, ignoring some columns. Implementors should handle possibility of null values. A multi-column type should be written to parameters starting from index.

Parameters:
st -
value - the object to write
index - statement parameter index
settable - an array indicating which columns to ignore
session -
Throws:
HibernateException
SQLException

nullSafeSet

public void nullSafeSet(PreparedStatement st,
                        Object value,
                        int index,
                        SessionImplementor session)
                 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.

Parameters:
st -
value - the object to write
index - statement parameter index
session -
Throws:
HibernateException
SQLException

setToXMLNode

public void setToXMLNode(org.dom4j.Node node,
                         Object value,
                         SessionFactoryImplementor factory)
                  throws HibernateException
A representation of the value to be embedded in an XML element.

Parameters:
value -
factory -
Returns:
String
Throws:
HibernateException

toLoggableString

public String toLoggableString(Object value,
                               SessionFactoryImplementor factory)
                        throws HibernateException
A representation of the value to be embedded in a log file.

Parameters:
value -
factory -
Returns:
String
Throws:
HibernateException

fromXMLNode

public Object fromXMLNode(org.dom4j.Node xml,
                          Mapping factory)
                   throws HibernateException
Parse the XML representation of an instance.

Parameters:
xml -
factory -
Returns:
an instance of the type
Throws:
HibernateException

getName

public String getName()
Returns the abbreviated name of the type.

Returns:
String the Hibernate type name

deepCopy

public Object deepCopy(Object value,
                       EntityMode entityMode,
                       SessionFactoryImplementor factory)
                throws HibernateException
Return a deep copy of the persistent state, stopping at entities and at collections.

Parameters:
value - generally a collection element or entity field
entityMode -
factory -
Returns:
Object a copy
Throws:
HibernateException

isMutable

public boolean isMutable()
Are objects of this type mutable. (With respect to the referencing object ... entities and collections are considered immutable because they manage their own internal state.)

Returns:
boolean

disassemble

public Serializable disassemble(Object value,
                                SessionImplementor session,
                                Object owner)
                         throws HibernateException
Return a cacheable "disassembled" representation of the object.

Parameters:
value - the value to cache
session - the session
owner - optional parent entity object (needed for collections)
Returns:
the disassembled, deep cloned state
Throws:
HibernateException

assemble

public Object assemble(Serializable cached,
                       SessionImplementor session,
                       Object owner)
                throws HibernateException
Reconstruct the object from its cached "disassembled" state.

Parameters:
cached - the disassembled state from the cache
session - the session
owner - the parent entity object
Returns:
the the object
Throws:
HibernateException

beforeAssemble

public void beforeAssemble(Serializable cached,
                           SessionImplementor session)
Called before assembling a query result set from the query cache, to allow batch fetching of entities missing from the second-level cache.


hydrate

public Object hydrate(ResultSet rs,
                      String[] names,
                      SessionImplementor session,
                      Object owner)
               throws HibernateException,
                      SQLException
Retrieve an instance of the mapped class, or the identifier of an entity or collection, from a JDBC resultset. This is useful for 2-phase property initialization - the second phase is a call to resolveIdentifier().

Parameters:
rs -
names - the column names
session - the session
owner - the parent entity
Returns:
Object an identifier or actual value
Throws:
HibernateException
SQLException
See Also:
resolve(Object, SessionImplementor, Object)

resolve

public Object resolve(Object value,
                      SessionImplementor session,
                      Object owner)
               throws HibernateException
Map identifiers to entities or collections. This is the second phase of 2-phase property initialization.

Parameters:
value - an identifier or value returned by hydrate()
owner - the parent entity
session - the session
Returns:
the given value, or the value associated with the identifier
Throws:
HibernateException
See Also:
hydrate(ResultSet, String[], SessionImplementor, Object)

semiResolve

public Object semiResolve(Object value,
                          SessionImplementor session,
                          Object owner)
                   throws HibernateException
Given a hydrated, but unresolved value, return a value that may be used to reconstruct property-ref associations.

Throws:
HibernateException

getSemiResolvedType

public Type getSemiResolvedType(SessionFactoryImplementor factory)
Get the type of a semi-resolved value.


replace

public Object replace(Object original,
                      Object target,
                      SessionImplementor session,
                      Object owner,
                      Map copyCache)
               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.

Parameters:
original - the value from the detached entity being merged
target - the value in the managed entity
Returns:
the value to be merged
Throws:
HibernateException

replace

public Object replace(Object original,
                      Object target,
                      SessionImplementor session,
                      Object owner,
                      Map copyCache,
                      ForeignKeyDirection foreignKeyDirection)
               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.

Parameters:
original - the value from the detached entity being merged
target - the value in the managed entity
Returns:
the value to be merged
Throws:
HibernateException

toColumnNullness

public boolean[] toColumnNullness(Object value,
                                  Mapping mapping)
Given an instance of the type, return an array of boolean, indicating which mapped columns would be null.

Parameters:
value - an instance of the type