Examples of org.hibernate.collection.spi.PersistentCollection

org.hibernate.collection.spi.PersistentCollection
Persistent collections are treated as value objects by Hibernate. ie. they have no independent existence beyond the object holding a reference to them. Unlike instances of entity classes, they are automatically deleted when unreferenced and automatically become persistent when held by a persistent object. Collections can be passed between different objects (change "roles") and this might cause their elements to move from one database table to another.

Hibernate "wraps" a java collection in an instance of PersistentCollection. This mechanism is designed to support tracking of changes to the collection's persistent state and lazy instantiation of collection elements. The downside is that only certain abstract collection types are supported and any extra semantics are lost

Applications should never use classes in this package directly, unless extending the "framework" here.

Changes to structure of the collection are recorded by the collection calling back to the session. Changes to mutable elements (ie. composite elements) are discovered by cloning their state when the collection is initialized and comparing at flush time. @author Gavin King

   * @param key The key of the collection's entry.
   */
  private void addCollection(PersistentCollection coll, CollectionEntry entry, Serializable key) {
    collectionEntries.put( coll, entry );
    CollectionKey collectionKey = new CollectionKey( entry.getLoadedPersister(), key );
    PersistentCollection old = 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)
    }
  }

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   * which might be a collection wrapper, an array, or an unwrapped
   * collection. Return null if there is no entry.
   */
  @Override
  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<PersistentCollection> wrappers = collectionEntries.keyIterator();
        while ( wrappers.hasNext() ) {
          PersistentCollection pc = wrappers.next();
          if ( pc.isWrapper(collection) ) {
            coll = pc;
            break;
          }
        }
      }

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      count = ois.readInt();
      if ( tracing ) LOG.trace("Starting deserialization of [" + count + "] collectionEntries entries");
      rtn.collectionEntries = IdentityMap.instantiateSequenced( count < INIT_COLL_SIZE ? INIT_COLL_SIZE : count );
      for ( int i = 0; i < count; i++ ) {
        final PersistentCollection pc = ( PersistentCollection ) ois.readObject();
        final CollectionEntry ce = CollectionEntry.deserialize( ois, session );
        pc.setCurrentSession( session );
        rtn.collectionEntries.put( pc, ce );
      }


      count = ois.readInt();
      if ( tracing ) LOG.trace("Starting deserialization of [" + count + "] arrayHolders entries");

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          MessageHelper.collectionInfoString( persister.getRole(), key ) );
    }
    final LoadingCollectionEntry loadingCollectionEntry = loadContexts.locateLoadingCollectionEntry( collectionKey );
    if ( loadingCollectionEntry == null ) {
      // look for existing collection as part of the persistence context
      PersistentCollection collection = loadContexts.getPersistenceContext().getCollection( collectionKey );
      if ( collection != null ) {
        if ( collection.wasInitialized() ) {
          LOG.trace( "Collection already initialized; ignoring" );
          return null; // ignore this row of results! Note the early exit
        }
        LOG.trace( "Collection not yet initialized; initializing" );
      }
      else {
        Object owner = loadContexts.getPersistenceContext().getCollectionOwner( key, persister );
        final boolean newlySavedEntity = owner != null
            && loadContexts.getPersistenceContext().getEntry( owner ).getStatus() != Status.LOADING;
        if ( newlySavedEntity ) {
          // important, to account for newly saved entities in query
          // todo : some kind of check for new status...
          LOG.trace( "Owning entity already loaded; ignoring" );
          return null;
        }
        // create one
        LOG.tracev( "Instantiating new collection [key={0}, rs={1}]", key, resultSet );
        collection = persister.getCollectionType().instantiate(
            loadContexts.getPersistenceContext().getSession(), persister, key );
      }
      collection.beforeInitialize( persister, -1 );
      collection.beginRead();
      localLoadingCollectionKeys.add( collectionKey );
      loadContexts.registerLoadingCollectionXRef( collectionKey, new LoadingCollectionEntry( resultSet, persister, key, collection ) );
      return collection;
    }
    if ( loadingCollectionEntry.getResultSet() == resultSet ) {

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    }
    else {
      return; //EARLY EXIT!
    }


    PersistentCollection collection = (PersistentCollection) pc;
    if ( collection.unsetSession( getSession() ) ) evictCollection(collection);
  }

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   * called by a collection that wants to initialize itself
   */
  public void onInitializeCollection(InitializeCollectionEvent event)
  throws HibernateException {


    PersistentCollection collection = event.getCollection();
    SessionImplementor source = event.getSession();


    CollectionEntry ce = source.getPersistenceContext().getCollectionEntry(collection);
    if (ce==null) throw new HibernateException("collection was evicted");
    if ( !collection.wasInitialized() ) {
      if ( LOG.isTraceEnabled() ) {
        LOG.tracev( "Initializing collection {0}",
            MessageHelper.collectionInfoString( ce.getLoadedPersister(), ce.getLoadedKey(),
            source.getFactory() ) );
      }

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   * @param key The key of the collection's entry.
   */
  private void addCollection(PersistentCollection coll, CollectionEntry entry, Serializable key) {
    collectionEntries.put( coll, entry );
    CollectionKey collectionKey = new CollectionKey( entry.getLoadedPersister(), key );
    PersistentCollection old = 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)
    }
  }

View Full Code Here

   * which might be a collection wrapper, an array, or an unwrapped
   * collection. Return null if there is no entry.
   */
  @Override
  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<PersistentCollection> wrappers = collectionEntries.keyIterator();
        while ( wrappers.hasNext() ) {
          PersistentCollection pc = wrappers.next();
          if ( pc.isWrapper(collection) ) {
            coll = pc;
            break;
          }
        }
      }

View Full Code Here


      count = ois.readInt();
      if ( tracing ) LOG.trace("Starting deserialization of [" + count + "] collectionEntries entries");
      rtn.collectionEntries = IdentityMap.instantiateSequenced( count < INIT_COLL_SIZE ? INIT_COLL_SIZE : count );
      for ( int i = 0; i < count; i++ ) {
        final PersistentCollection pc = ( PersistentCollection ) ois.readObject();
        final CollectionEntry ce = CollectionEntry.deserialize( ois, session );
        pc.setCurrentSession( session );
        rtn.collectionEntries.put( pc, ce );
      }


      count = ois.readInt();
      if ( tracing ) LOG.trace("Starting deserialization of [" + count + "] arrayHolders entries");

View Full Code Here

  @Override
  public void execute() throws HibernateException {
    final Serializable id = getKey();
    final SessionImplementor session = getSession();
    final CollectionPersister persister = getPersister();
    final PersistentCollection collection = getCollection();
    boolean affectedByFilters = persister.isAffectedByEnabledFilters(session);


    preUpdate();


    if ( !collection.wasInitialized() ) {
      if ( !collection.hasQueuedOperations() ) throw new AssertionFailure( "no queued adds" );
      //do nothing - we only need to notify the cache...
    }
    else if ( !affectedByFilters && collection.empty() ) {
      if ( !emptySnapshot ) persister.remove( id, session );
    }
    else if ( collection.needsRecreate(persister) ) {
      if (affectedByFilters) {
        throw new HibernateException(
          "cannot recreate collection while filter is enabled: " + 
          MessageHelper.collectionInfoString( persister, id, persister.getFactory() )
        );

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com.fasterxml.jackson.datatype.hibernate4.PersistentCollectionSerializer

org.hibernate.action.internal.CollectionRecreateAction

org.hibernate.action.internal.CollectionRemoveAction

org.hibernate.action.internal.CollectionUpdateAction

org.hibernate.action.internal.QueuedOperationCollectionAction

org.hibernate.engine.internal.StatefulPersistenceContext

org.hibernate.engine.loading.internal.CollectionLoadContext

org.hibernate.engine.spi.BatchFetchQueue

org.hibernate.event.internal.AbstractFlushingEventListener

org.hibernate.event.internal.DefaultInitializeCollectionEventListener

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