Example usage for org.hibernate.persister.collection QueryableCollection getElementByIndex

Introduction

In this page you can find the example usage for org.hibernate.persister.collection QueryableCollection getElementByIndex.

Prototype

Object getElementByIndex(Serializable key, Object index, SharedSessionContractImplementor session,
            Object owner);

Source Link

Usage

From source file:org.eclipse.emf.cdo.server.internal.hibernate.HibernateStoreChunkReader.java

License:Open Source License

public List<Chunk> executeRead() {
    // get a transaction, the hibernateStoreAccessor is placed in a threadlocal
    // so all db access uses the same session.
    final Session session = getAccessor().getHibernateSession();

    // reread the revision as it is probably unreferenced
    final InternalCDORevision latestRevision = getLatestRevision(session);
    Object value = latestRevision.getValue(getFeature());
    if (value instanceof WrappedHibernateList) {
        value = ((WrappedHibernateList) value).getDelegate();
    }//from   www.j  a  va  2 s  .  co  m

    // hibernate details...
    boolean useExtraLazyMode = false;
    boolean standardCDOList = false;
    QueryableCollection persister = null;
    CollectionEntry entry = null;
    if (value instanceof PersistentCollection) {
        final PersistentCollection persistentCollection = (PersistentCollection) value;
        persister = (QueryableCollection) ((SessionFactoryImplementor) session.getSessionFactory())
                .getCollectionPersister(persistentCollection.getRole());
        entry = ((SessionImplementor) session).getPersistenceContext().getCollectionEntry(persistentCollection);

        useExtraLazyMode = !persister.getElementType().isEntityType();
        if (useExtraLazyMode && ((PersistentCollection) value).hasQueuedOperations()) {
            session.flush();
        }
    } else {
        standardCDOList = true;
    }

    final List<Chunk> chunks = getChunks();
    for (Chunk chunk : chunks) {
        final int startIndex = chunk.getStartIndex();
        final int maxElements = chunk.size();
        if (standardCDOList) {
            // for eattributes just read them all, no chunking there...
            final CDOList list = (CDOList) value;
            if (startIndex >= list.size()) {
                return chunks;
            }
            for (int i = startIndex; i < startIndex + maxElements; i++) {
                if (i >= list.size()) {
                    break;
                }
                addToChunk(chunk, i - startIndex, list.get(i));
            }
        } else if (useExtraLazyMode) {
            if (getFeature() instanceof EReference) {
                for (int i = startIndex; i < startIndex + maxElements; i++) {
                    final Object object = persister.getElementByIndex(entry.getLoadedKey(), i,
                            (SessionImplementor) session, latestRevision);
                    // could happen if the index > size)
                    if (object == null) {
                        continue;
                    }
                    addToChunk(chunk, i - startIndex, object);
                }
            } else {
                // for eattributes just read them all, no chunking there...
                final List<?> list = (List<?>) value;
                if (startIndex >= list.size()) {
                    return chunks;
                }
                for (int i = startIndex; i < startIndex + maxElements; i++) {
                    if (i >= list.size()) {
                        break;
                    }
                    addToChunk(chunk, i - startIndex, list.get(i));
                }
            }
        } else {
            final Query filterQuery = session.createFilter(value, "");
            filterQuery.setMaxResults(maxElements);
            filterQuery.setFirstResult(startIndex);
            int i = 0;
            for (Object object : filterQuery.list()) {
                addToChunk(chunk, i++, object);
            }
        }
    }
    return chunks;
}

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