statefulpersistencecontext.java

hibernate-3.1.3-all-src.zip 面向对象的访问数据库工具

	public boolean containsCollection(PersistentCollection collection) {
		return collectionEntries.containsKey(collection);
	}

	public boolean containsProxy(Object entity) {
		return proxiesByKey.containsValue( entity );
	}
	
	/**
	 * Takes the given object and, if it represents a proxy, reassociates it with this event source.
	 *
	 * @param value The possible proxy to be reassociated.
	 * @return Whether the passed value represented an actual proxy which got initialized.
	 * @throws MappingException
	 */
	public boolean reassociateIfUninitializedProxy(Object value) throws MappingException {
		if ( value instanceof ElementWrapper ) {
			value = ( (ElementWrapper) value ).getElement();
		}
		
		if ( !Hibernate.isInitialized(value) ) {
			HibernateProxy proxy = (HibernateProxy) value;
			LazyInitializer li = proxy.getHibernateLazyInitializer();
			reassociateProxy(li, proxy);
			return true;
		}
		else {
			return false;
		}
	}

	/**
	 * If a deleted entity instance is re-saved, and it has a proxy, we need to
	 * reset the identifier of the proxy 
	 */
	public void reassociateProxy(Object value, Serializable id) throws MappingException {
		if ( value instanceof ElementWrapper ) {
			value = ( (ElementWrapper) value ).getElement();
		}
		
		if ( value instanceof HibernateProxy ) {
			if ( log.isDebugEnabled() ) log.debug("setting proxy identifier: " + id);
			HibernateProxy proxy = (HibernateProxy) value;
			LazyInitializer li = proxy.getHibernateLazyInitializer();
			li.setIdentifier(id);
			reassociateProxy(li, proxy);
		}
	}

	/**
	 * Associate a proxy that was instantiated by another session with this session
	 */
	private void reassociateProxy(LazyInitializer li, HibernateProxy proxy) throws HibernateException {
		if ( li.getSession() != this ) {
			EntityPersister persister = session.getFactory().getEntityPersister( li.getEntityName() );
			EntityKey key = new EntityKey( li.getIdentifier(), persister, session.getEntityMode() );
			if ( !proxiesByKey.containsKey(key) ) proxiesByKey.put(key, proxy); // any earlier proxy takes precedence
			proxy.getHibernateLazyInitializer().setSession(session);
		}
	}

	/**
	 * Get the entity instance underlying the given proxy, throwing
	 * an exception if the proxy is uninitialized. If the given object
	 * is not a proxy, simply return the argument.
	 */
	public Object unproxy(Object maybeProxy) throws HibernateException {
		if ( maybeProxy instanceof ElementWrapper ) {
			maybeProxy = ( (ElementWrapper) maybeProxy ).getElement();
		}
		
		if ( maybeProxy instanceof HibernateProxy ) {
			HibernateProxy proxy = (HibernateProxy) maybeProxy;
			LazyInitializer li = proxy.getHibernateLazyInitializer();
			if ( li.isUninitialized() ) {
				throw new PersistentObjectException(
						"object was an uninitialized proxy for " +
						li.getEntityName()
				);
			}
			return li.getImplementation(); //unwrap the object
		}
		else {
			return maybeProxy;
		}
	}

	/**
	 * Possibly unproxy the given reference and reassociate it with the current session.
	 *
	 * @param maybeProxy The reference to be unproxied if it currently represents a proxy.
	 * @return The unproxied instance.
	 * @throws HibernateException
	 */
	public Object unproxyAndReassociate(Object maybeProxy) throws HibernateException {
		if ( maybeProxy instanceof ElementWrapper ) {
			maybeProxy = ( (ElementWrapper) maybeProxy ).getElement();
		}
		
		if ( maybeProxy instanceof HibernateProxy ) {
			HibernateProxy proxy = (HibernateProxy) maybeProxy;
			LazyInitializer li = proxy.getHibernateLazyInitializer();
			reassociateProxy(li, proxy);
			return li.getImplementation(); //initialize + unwrap the object
		}
		else {
			return maybeProxy;
		}
	}

	/**
	 * Attempts to check whether the given key represents an entity already loaded within the
	 * current session.
	 * @param object The entity reference against which to perform the uniqueness check.
	 * @throws HibernateException
	 */
	public void checkUniqueness(EntityKey key, Object object) throws HibernateException {
		Object entity = getEntity(key);
		if ( entity == object ) {
			throw new AssertionFailure( "object already associated, but no entry was found" );
		}
		if ( entity != null ) {
			throw new NonUniqueObjectException( key.getIdentifier(), key.getEntityName() );
		}
	}

	/**
	 * If the existing proxy is insufficiently "narrow" (derived), instantiate a new proxy
	 * and overwrite the registration of the old one. This breaks == and occurs only for
	 * "class" proxies rather than "interface" proxies. Also init the proxy to point to
	 * the given target implementation if necessary.
	 *
	 * @param proxy The proxy instance to be narrowed.
	 * @param persister The persister for the proxied entity.
	 * @param key The internal cache key for the proxied entity.
	 * @param object (optional) the actual proxied entity instance.
	 * @return An appropriately narrowed instance.
	 * @throws HibernateException
	 */
	public Object narrowProxy(Object proxy, EntityPersister persister, EntityKey key, Object object)
	throws HibernateException {
		
		boolean alreadyNarrow = persister.getConcreteProxyClass( session.getEntityMode() )
				.isAssignableFrom( proxy.getClass() );
		
		if ( !alreadyNarrow ) {
			if ( PROXY_WARN_LOG.isWarnEnabled() ) {
				PROXY_WARN_LOG.warn(
						"Narrowing proxy to " +
						persister.getConcreteProxyClass( session.getEntityMode() ) +
						" - this operation breaks =="
				);
			}

			if ( object != null ) {
				proxiesByKey.remove(key);
				return object; //return the proxied object
			}
			else {
				proxy = persister.createProxy( key.getIdentifier(), session );
				proxiesByKey.put(key, proxy); //overwrite old proxy
				return proxy;
			}
			
		}
		else {
			
			if ( object != null ) {
				LazyInitializer li = ( (HibernateProxy) proxy ).getHibernateLazyInitializer();
				li.setImplementation(object);
			}
			
			return proxy;
			
		}
		
	}

	/**
	 * Return the existing proxy associated with the given <tt>EntityKey</tt>, or the
	 * third argument (the entity associated with the key) if no proxy exists. Init
	 * the proxy to the target implementation, if necessary.
	 */
	public Object proxyFor(EntityPersister persister, EntityKey key, Object impl) 
	throws HibernateException {
		if ( !persister.hasProxy() ) return impl;
		Object proxy = proxiesByKey.get(key);
		if ( proxy != null ) {
			return narrowProxy(proxy, persister, key, impl);
		}
		else {
			return impl;
		}
	}

	/**
	 * Return the existing proxy associated with the given <tt>EntityKey</tt>, or the
	 * argument (the entity associated with the key) if no proxy exists.
	 * (slower than the form above)
	 */
	public Object proxyFor(Object impl) throws HibernateException {
		EntityEntry e = getEntry(impl);
		EntityPersister p = e.getPersister();
		return proxyFor( p, new EntityKey( e.getId(), p, session.getEntityMode() ), impl );
	}

	/**
	 * Get the entity that owns this persistent collection
	 */
	public Object getCollectionOwner(Serializable key, CollectionPersister collectionPersister) throws MappingException {
		return getEntity( new EntityKey( key, collectionPersister.getOwnerEntityPersister(), session.getEntityMode() ) );
	}

	/**
	 * add a collection we just loaded up (still needs initializing)
	 */
	public void addUninitializedCollection(CollectionPersister persister, PersistentCollection collection, Serializable id) {
		CollectionEntry ce = new CollectionEntry(collection, persister, id, flushing);
		addCollection(collection, ce, id);
	}

	/**
	 * add a detached uninitialized collection
	 */
	public void addUninitializedDetachedCollection(CollectionPersister persister, PersistentCollection collection) {
		CollectionEntry ce = new CollectionEntry( persister, collection.getKey() );
		addCollection( collection, ce, collection.getKey() );
	}

	/**
	 * Add a new collection (ie. a newly created one, just instantiated by the
	 * application, with no database state or snapshot)
	 * @param collection The collection to be associated with the persistence context
	 */
	public void addNewCollection(CollectionPersister persister, PersistentCollection collection)
	throws HibernateException {
		addCollection(collection, persister);
	}
	
	/**
	 * Add an collection to the cache, with a given collection entry
	 */
	private void addCollection(PersistentCollection coll, CollectionEntry entry, Serializable key) {
		collectionEntries.put(coll, entry);
		CollectionKey collectionKey = new CollectionKey( entry.getLoadedPersister(), key, session.getEntityMode() );
		PersistentCollection old = (PersistentCollection) collectionsByKey.put(collectionKey, coll);
		if ( old != null ) {
			if (old==coll) throw new AssertionFailure("bug adding collection twice");
			// or should it actually throw an exception?
			old.unsetSession(session);
			collectionEntries.remove(old);
			// watch out for a case where old is still referenced
			// somewhere in the object graph! (which is a user error)
		}
	}

	/**
	 * Add a collection to the cache, creating a new collection entry for it
	 */
	private void addCollection(PersistentCollection collection, CollectionPersister persister) 
	throws HibernateException {
		CollectionEntry ce = new CollectionEntry(persister, collection);
		collectionEntries.put(collection, ce);
	}

	/**
	 * add an (initialized) collection that was created by another session and passed
	 * into update() (ie. one with a snapshot and existing state on the database)
	 */
	public void addInitializedDetachedCollection(CollectionPersister collectionPersister, PersistentCollection collection) 
	throws HibernateException {
		if ( collection.isUnreferenced() ) {
			//treat it just like a new collection
			addCollection( collection, collectionPersister );
		}
		else {
			CollectionEntry ce = new CollectionEntry( collection, session.getFactory() );
			addCollection( collection, ce, collection.getKey() );
		}
	}

	/**
	 * add a collection we just pulled out of the cache (does not need initializing)
	 */
	public CollectionEntry addInitializedCollection(CollectionPersister persister, PersistentCollection collection, Serializable id)
	throws HibernateException {
		CollectionEntry ce = new CollectionEntry(collection, persister, id, flushing);
		ce.postInitialize(collection);
		addCollection(collection, ce, id);
		return ce;
	}
	
	/**
	 * Get the collection instance associated with the <tt>CollectionKey</tt>
	 */
	public PersistentCollection getCollection(CollectionKey collectionKey) {
		return (PersistentCollection) collectionsByKey.get(collectionKey);
	}
	
	/**
	 * Register a collection for non-lazy loading at the end of the
	 * two-phase load
	 */
	public void addNonLazyCollection(PersistentCollection collection) {
		nonlazyCollections.add(collection);
	}

	/**
	 * Force initialization of all non-lazy collections encountered during
	 * the current two-phase load (actually, this is a no-op, unless this
	 * is the "outermost" load)
	 */
	public void initializeNonLazyCollections() throws HibernateException {
		if ( loadCounter == 0 ) {
			log.debug( "initializing non-lazy collections" );
			//do this work only at the very highest level of the load
			loadCounter++; //don't let this method be called recursively
			try {
				int size;
				while ( ( size = nonlazyCollections.size() ) > 0 ) {
					//note that each iteration of the loop may add new elements
					( (PersistentCollection) nonlazyCollections.remove( size - 1 ) ).forceInitialization();
				}
			}
			finally {
				loadCounter--;
				clearNullProperties();
			}
		}
	}


	/**
	 * Get the <tt>PersistentCollection</tt> object for an array
	 */
	public PersistentCollection getCollectionHolder(Object array) {
		return (PersistentCollection) arrayHolders.get(array);
	}

	/**
	 * Register a <tt>PersistentCollection</tt> object for an array.
	 * Associates a holder with an array - MUST be called after loading 
	 * array, since the array instance is not created until endLoad().
	 */
	public void addCollectionHolder(PersistentCollection holder) {
		//TODO:refactor + make this method private
		arrayHolders.put( holder.getValue(), holder );
	}

	public PersistentCollection removeCollectionHolder(Object array) {
		return (PersistentCollection) arrayHolders.remove(array);
	}

	/**
	 * Get the snapshot of the pre-flush collection state
	 */
	public Serializable getSnapshot(PersistentCollection coll) {
		return getCollectionEntry(coll).getSnapshot();
	}

	/**
	 * Get the collection entry for a collection passed to filter,
	 * which might be a collection wrapper, an array, or an unwrapped
	 * collection. Return null if there is no entry.
	 */
	public CollectionEntry getCollectionEntryOrNull(Object collection) {
		PersistentCollection coll;
		if ( collection instanceof PersistentCollection ) {
			coll = (PersistentCollection) collection;
			//if (collection==null) throw new TransientObjectException("Collection was not yet persistent");
		}
		else {
			coll = getCollectionHolder(collection);
			if ( coll == null ) {
				//it might be an unwrapped collection reference!
				//try to find a wrapper (slowish)
				Iterator wrappers = IdentityMap.keyIterator(collectionEntries);
				while ( wrappers.hasNext() ) {
					PersistentCollection pc = (PersistentCollection) wrappers.next();
					if ( pc.isWrapper(collection) ) {
						coll = pc;
						break;
					}
				}
			}
		}

		return (coll == null) ? null : getCollectionEntry(coll);
	}

	/**
	 * Get an existing proxy by key
	 */
	public Object getProxy(EntityKey key) {
		return proxiesByKey.get(key);
	}

	/**
	 * Add a proxy to the session cache
	 */
	public void addProxy(EntityKey key, Object proxy) {
		proxiesByKey.put(key, proxy);
	}

	/**
	 * Remove a proxy from the session cache
	 */
	public Object removeProxy(EntityKey key) {
		return proxiesByKey.remove(key);
	}

	/**
	 * Record the fact that an entity does not exist in the database
	 * 
	 * @param key the primary key of the entity
	 */
	/*public void addNonExistantEntityKey(EntityKey key) {
		nonExistantEntityKeys.add(key);
	}*/

	/**
	 * Record the fact that an entity does not exist in the database
	 * 
	 * @param key a unique key of the entity
	 */
	/*public void addNonExistantEntityUniqueKey(EntityUniqueKey key) {
		nonExistentEntityUniqueKeys.add(key);
	}*/

	/*public void removeNonExist(EntityKey key) {
		nonExistantEntityKeys.remove(key);