org.hibernate

Interface Interceptor

All Known Implementing Classes:

EmptyInterceptor

public interface Interceptor

Allows user code to inspect and/or change property values.

Inspection occurs before property values are written and after they are read from the database.

There might be a single instance of Interceptor for a SessionFactory, or a new instance might be specified for each Session. Whichever approach is used, the interceptor must be serializable if the Session is to be serializable. This means that SessionFactory-scoped interceptors should implement readResolve().

The Session may not be invoked from a callback (nor may a callback cause a collection or proxy to be lazily initialized).

Instead of implementing this interface directly, it is usually better to extend EmptyInterceptor and override only the callback methods of interest.

Author:

Gavin King

See Also:

SessionBuilder.interceptor(Interceptor), SharedSessionBuilder.interceptor(), Configuration.setInterceptor(Interceptor), EmptyInterceptor

Method Summary

Methods

Modifier and Type	Method and Description
void	afterTransactionBegin(Transaction tx) Called when a Hibernate transaction is begun via the Hibernate Transaction API.
void	afterTransactionCompletion(Transaction tx) Called after a transaction is committed or rolled back.
void	beforeTransactionCompletion(Transaction tx) Called before a transaction is committed (but not before rollback).
int[]	findDirty(Object entity, Serializable id, Object[] currentState, Object[] previousState, String[] propertyNames, Type[] types) Called from flush().
Object	getEntity(String entityName, Serializable id) Get a fully loaded entity instance that is cached externally
String	getEntityName(Object object) Get the entity name for a persistent or transient instance
Object	instantiate(String entityName, EntityMode entityMode, Serializable id) Instantiate the entity class.
Boolean	isTransient(Object entity) Called to distinguish between transient and detached entities.
void	onCollectionRecreate(Object collection, Serializable key) Called before a collection is (re)created.
void	onCollectionRemove(Object collection, Serializable key) Called before a collection is deleted.
void	onCollectionUpdate(Object collection, Serializable key) Called before a collection is updated.
void	onDelete(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) Called before an object is deleted.
boolean	onFlushDirty(Object entity, Serializable id, Object[] currentState, Object[] previousState, String[] propertyNames, Type[] types) Called when an object is detected to be dirty, during a flush.
boolean	onLoad(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) Called just before an object is initialized.
String	onPrepareStatement(String sql) Called when sql string is being prepared.
boolean	onSave(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) Called before an object is saved.
void	postFlush(Iterator entities) Called after a flush that actually ends in execution of the SQL statements required to synchronize in-memory state with the database.
void	preFlush(Iterator entities) Called before a flush

Method Detail

onLoad

boolean onLoad(Object entity,
             Serializable id,
             Object[] state,
             String[] propertyNames,
             Type[] types)
               throws CallbackException

Called just before an object is initialized. The interceptor may change the state, which will be propagated to the persistent object. Note that when this method is called, entity will be an empty uninitialized instance of the class.

NOTE: The indexes across the state, propertyNames and types arrays match.

Parameters:

entity - The entity instance being loaded

id - The identifier value being loaded

state - The entity state (which will be pushed into the entity instance)

propertyNames - The names of the entity properties, corresponding to the state.

types - The types of the entity properties, corresponding to the state.

Returns:

true if the user modified the state in any way.

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

onFlushDirty

boolean onFlushDirty(Object entity,
                   Serializable id,
                   Object[] currentState,
                   Object[] previousState,
                   String[] propertyNames,
                   Type[] types)
                     throws CallbackException

Called when an object is detected to be dirty, during a flush. The interceptor may modify the detected currentState, which will be propagated to both the database and the persistent object. Note that not all flushes end in actual synchronization with the database, in which case the new currentState will be propagated to the object, but not necessarily (immediately) to the database. It is strongly recommended that the interceptor not modify the previousState.

NOTE: The indexes across the currentState, previousState, propertyNames and types arrays match.

Parameters:

entity - The entity instance detected as being dirty and being flushed

id - The identifier of the entity

currentState - The entity's current state

previousState - The entity's previous (load time) state.

propertyNames - The names of the entity properties

types - The types of the entity properties

Returns:

true if the user modified the currentState in any way.

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

onSave

boolean onSave(Object entity,
             Serializable id,
             Object[] state,
             String[] propertyNames,
             Type[] types)
               throws CallbackException

Called before an object is saved. The interceptor may modify the state, which will be used for the SQL INSERT and propagated to the persistent object.

Parameters:

entity - The entity instance whose state is being inserted

id - The identifier of the entity

state - The state of the entity which will be inserted

propertyNames - The names of the entity properties.

types - The types of the entity properties

Returns:

true if the user modified the state in any way.

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

onDelete

void onDelete(Object entity,
            Serializable id,
            Object[] state,
            String[] propertyNames,
            Type[] types)
              throws CallbackException

Called before an object is deleted. It is not recommended that the interceptor modify the state.

Parameters:

entity - The entity instance being deleted

id - The identifier of the entity

state - The state of the entity

propertyNames - The names of the entity properties.

types - The types of the entity properties

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

onCollectionRecreate

void onCollectionRecreate(Object collection,
                        Serializable key)
                          throws CallbackException

Called before a collection is (re)created.

Parameters:

collection - The collection instance.

key - The collection key value.

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

onCollectionRemove

void onCollectionRemove(Object collection,
                      Serializable key)
                        throws CallbackException

Called before a collection is deleted.

Parameters:

collection - The collection instance.

key - The collection key value.

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

onCollectionUpdate

void onCollectionUpdate(Object collection,
                      Serializable key)
                        throws CallbackException

Called before a collection is updated.

Parameters:

collection - The collection instance.

key - The collection key value.

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

preFlush

void preFlush(Iterator entities)
              throws CallbackException

Called before a flush

Parameters:

entities - The entities to be flushed

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

postFlush

void postFlush(Iterator entities)
               throws CallbackException

Called after a flush that actually ends in execution of the SQL statements required to synchronize in-memory state with the database.

Parameters:

entities - The entities that were flushed.

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

isTransient

Boolean isTransient(Object entity)

Called to distinguish between transient and detached entities. The return value determines the state of the entity with respect to the current session.

• Boolean.TRUE - the entity is transient
• Boolean.FALSE - the entity is detached
• null - Hibernate uses the unsaved-value mapping and other heuristics to determine if the object is unsaved

Parameters:

entity - a transient or detached entity

Returns:

Boolean or null to choose default behaviour

findDirty

int[] findDirty(Object entity,
              Serializable id,
              Object[] currentState,
              Object[] previousState,
              String[] propertyNames,
              Type[] types)

Called from flush(). The return value determines whether the entity is updated

• an array of property indices - the entity is dirty
• an empty array - the entity is not dirty
• null - use Hibernate's default dirty-checking algorithm

Parameters:

entity - The entity for which to find dirty properties.

id - The identifier of the entity

currentState - The current entity state as taken from the entity instance

previousState - The state of the entity when it was last synchronized (generally when it was loaded)

propertyNames - The names of the entity properties.

types - The types of the entity properties

Returns:

array of dirty property indices or null to indicate Hibernate should perform default behaviour

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

instantiate

Object instantiate(String entityName,
                 EntityMode entityMode,
                 Serializable id)
                   throws CallbackException

Instantiate the entity class. Return null to indicate that Hibernate should use the default constructor of the class. The identifier property of the returned instance should be initialized with the given identifier.

Parameters:

entityName - the name of the entity

entityMode - The type of entity instance to be returned.

id - the identifier of the new instance

Returns:

an instance of the class, or null to choose default behaviour

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

getEntityName

String getEntityName(Object object)
                     throws CallbackException

Get the entity name for a persistent or transient instance

Parameters:

object - an entity instance

Returns:

the name of the entity

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

getEntity

Object getEntity(String entityName,
               Serializable id)
                 throws CallbackException

Get a fully loaded entity instance that is cached externally

Parameters:

entityName - the name of the entity

id - the instance identifier

Returns:

a fully initialized entity

Throws:

CallbackException - Thrown if the interceptor encounters any problems handling the callback.

afterTransactionBegin

void afterTransactionBegin(Transaction tx)

Called when a Hibernate transaction is begun via the Hibernate Transaction API. Will not be called if transactions are being controlled via some other mechanism (CMT, for example).

Parameters:

tx - The Hibernate transaction facade object

beforeTransactionCompletion

void beforeTransactionCompletion(Transaction tx)

Called before a transaction is committed (but not before rollback).

Parameters:

tx - The Hibernate transaction facade object

afterTransactionCompletion

void afterTransactionCompletion(Transaction tx)

Called after a transaction is committed or rolled back.

Parameters:

tx - The Hibernate transaction facade object

onPrepareStatement

String onPrepareStatement(String sql)

Called when sql string is being prepared.

Parameters:

sql - sql to be prepared

Returns:

original or modified sql