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

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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:: SessionFactory.openSession(Interceptor), Configuration.setInterceptor(Interceptor), EmptyInterceptor

Method Summary

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

public 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.

Returns:: true if the user modified the state in any way.
Throws:: CallbackException

onFlushDirty

public 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.

Returns:: true if the user modified the currentState in any way.
Throws:: CallbackException

onSave

public 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.

Returns:: true if the user modified the state in any way.
Throws:: CallbackException

onDelete

public 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.

Throws:: CallbackException

onCollectionRecreate

public void onCollectionRecreate(Object collection,
                                 Serializable key)
                          throws CallbackException

Called before a collection is (re)created.

Throws:: CallbackException

onCollectionRemove

public void onCollectionRemove(Object collection,
                               Serializable key)
                        throws CallbackException

Called before a collection is deleted.

Throws:: CallbackException

onCollectionUpdate

public void onCollectionUpdate(Object collection,
                               Serializable key)
                        throws CallbackException

Called before a collection is updated.

Throws:: CallbackException

preFlush

public void preFlush(Iterator entities)
              throws CallbackException

Called before a flush

Throws:: CallbackException

postFlush

public 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.

Throws:: CallbackException

isTransient

public 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

public 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 - a persistent entity
Returns:: array of dirty property indices or null to choose default behaviour

instantiate

public 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

getEntityName

public 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

getEntity

public 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

afterTransactionBegin

public 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).

beforeTransactionCompletion

public void beforeTransactionCompletion(Transaction tx)

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

afterTransactionCompletion

public void afterTransactionCompletion(Transaction tx)

Called after a transaction is committed or rolled back.

onPrepareStatement

public String onPrepareStatement(String sql)

Called when sql string is being prepared.

Parameters:: sql - sql to be prepared
Returns:: original or modified sql