/**********************************************************************
Copyright (c) 2005 Andy Jefferson and others. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
Contributors:
...
**********************************************************************/
package org.datanucleus.store.types.wrappers.backed;
import java.io.ObjectStreamException;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Spliterator;
import java.util.stream.Stream;
import org.datanucleus.ClassLoaderResolver;
import org.datanucleus.ExecutionContext;
import org.datanucleus.exceptions.NucleusDataStoreException;
import org.datanucleus.exceptions.NucleusUserException;
import org.datanucleus.flush.CollectionAddOperation;
import org.datanucleus.flush.CollectionClearOperation;
import org.datanucleus.flush.CollectionRemoveOperation;
import org.datanucleus.metadata.AbstractMemberMetaData;
import org.datanucleus.metadata.FieldPersistenceModifier;
import org.datanucleus.state.ObjectProvider;
import org.datanucleus.state.RelationshipManager;
import org.datanucleus.store.BackedSCOStoreManager;
import org.datanucleus.store.types.SCOCollection;
import org.datanucleus.store.types.SCOCollectionIterator;
import org.datanucleus.store.types.SCOUtils;
import org.datanucleus.store.types.scostore.SetStore;
import org.datanucleus.store.types.scostore.Store;
import org.datanucleus.util.Localiser;
import org.datanucleus.util.NucleusLogger;
/**
* A mutable second-class SortedSet object.
* This class extends AbstractSet, using that class to contain the current objects, and the backing SetStore
* to be the interface to the datastore. A "backing store" is not present for datastores that dont use
* DatastoreClass, or if the container is serialised or non-persistent.
*
* <H3>Modes of Operation</H3>
* The user can operate the list in 2 modes.
* The <B>cached</B> mode will use an internal cache of the elements (in the "delegate") reading them at
* the first opportunity and then using the cache thereafter.
* The <B>non-cached</B> mode will just go direct to the "backing store" each call.
*
* <H3>Mutators</H3>
* When the "backing store" is present any updates are passed direct to the datastore as well as to the "delegate".
* If the "backing store" isn't present the changes are made to the "delegate" only.
*
* <H3>Accessors</H3>
* When any accessor method is invoked, it typically checks whether the container has been loaded from its
* "backing store" (where present) and does this as necessary. Some methods (<B>size()</B>) just check if
* everything is loaded and use the delegate if possible, otherwise going direct to the datastore.
*/
public class SortedSet<E> extends org.datanucleus.store.types.wrappers.SortedSet<E> implements BackedSCO
{
protected transient SetStore<E> backingStore;
protected transient boolean allowNulls = false;
protected transient boolean useCache = true;
protected transient boolean isCacheLoaded = false;
protected transient boolean initialising = false;
/**
* Constructor, using the ObjectProvider of the "owner" and the field name.
* @param op The owner ObjectProvider
* @param mmd Metadata for the member
*/
public SortedSet(ObjectProvider op, AbstractMemberMetaData mmd)
{
super(op, mmd);
ExecutionContext ec = op.getExecutionContext();
allowNulls = SCOUtils.allowNullsInContainer(allowNulls, mmd);
useCache = SCOUtils.useContainerCache(op, mmd);
if (!SCOUtils.collectionHasSerialisedElements(mmd) && mmd.getPersistenceModifier() == FieldPersistenceModifier.PERSISTENT)
{
ClassLoaderResolver clr = ec.getClassLoaderResolver();
this.backingStore = (SetStore)((BackedSCOStoreManager)ownerOP.getStoreManager()).getBackingStoreForField(clr, mmd, java.util.SortedSet.class);
}
// Set up our delegate, using a suitable comparator
Comparator comparator = SCOUtils.getComparator(mmd, op.getExecutionContext().getClassLoaderResolver());
if (comparator != null)
{
this.delegate = new java.util.TreeSet(comparator);
}
else
{
this.delegate = new java.util.TreeSet();
}
if (NucleusLogger.PERSISTENCE.isDebugEnabled())
{
NucleusLogger.PERSISTENCE.debug(SCOUtils.getContainerInfoMessage(ownerOP, ownerMmd.getName(), this,
useCache, allowNulls, SCOUtils.useCachedLazyLoading(ownerOP, ownerMmd)));
}
}
public void initialise(java.util.SortedSet<E> newValue, Object oldValue)
{
if (newValue != null)
{
// Check for the case of serialised PC elements, and assign ObjectProviders to the elements without
if (SCOUtils.collectionHasSerialisedElements(ownerMmd) && ownerMmd.getCollection().elementIsPersistent())
{
ExecutionContext ec = ownerOP.getExecutionContext();
Iterator iter = newValue.iterator();
while (iter.hasNext())
{
Object pc = iter.next();
ObjectProvider objSM = ec.findObjectProvider(pc);
if (objSM == null)
{
objSM = ec.getNucleusContext().getObjectProviderFactory().newForEmbedded(ec, pc, false, ownerOP, ownerMmd.getAbsoluteFieldNumber());
}
}
}
if (NucleusLogger.PERSISTENCE.isDebugEnabled())
{
NucleusLogger.PERSISTENCE.debug(Localiser.msg("023008", ownerOP.getObjectAsPrintable(), ownerMmd.getName(), "" + newValue.size()));
}
// Detect which objects are added and which are deleted
initialising = true;
if (useCache)
{
Collection oldColl = (Collection)oldValue;
if (oldColl != null)
{
delegate.addAll(oldColl);
}
isCacheLoaded = true;
SCOUtils.updateCollectionWithCollection(ownerOP.getExecutionContext().getApiAdapter(), this, newValue);
}
else
{
java.util.Collection oldColl = (java.util.Collection)oldValue;
if (oldColl instanceof SCOCollection)
{
oldColl = (java.util.Collection) ((SCOCollection)oldColl).getValue();
}
for (E elem : newValue)
{
if (oldColl == null || !oldColl.contains(elem))
{
add(elem);
}
}
if (oldColl != null)
{
Iterator iter = oldColl.iterator();
while (iter.hasNext())
{
Object elem = iter.next();
if (!newValue.contains(elem))
{
remove(elem);
}
}
}
}
initialising = false;
}
}
/**
* Method to initialise the SCO from an existing value.
* @param c The object to set from
*/
public void initialise(java.util.SortedSet c)
{
if (c != null)
{
// Check for the case of serialised PC elements, and assign ObjectProviders to the elements without
if (SCOUtils.collectionHasSerialisedElements(ownerMmd) && ownerMmd.getCollection().elementIsPersistent())
{
ExecutionContext ec = ownerOP.getExecutionContext();
Iterator iter = c.iterator();
while (iter.hasNext())
{
Object pc = iter.next();
ObjectProvider objSM = ec.findObjectProvider(pc);
if (objSM == null)
{
objSM = ec.getNucleusContext().getObjectProviderFactory().newForEmbedded(ec, pc, false, ownerOP, ownerMmd.getAbsoluteFieldNumber());
}
}
}
if (backingStore != null && useCache && !isCacheLoaded)
{
// Mark as loaded
isCacheLoaded = true;
}
if (NucleusLogger.PERSISTENCE.isDebugEnabled())
{
NucleusLogger.PERSISTENCE.debug(Localiser.msg("023007", ownerOP.getObjectAsPrintable(), ownerMmd.getName(), "" + c.size()));
}
delegate.clear();
delegate.addAll(c);
}
}
/**
* Method to initialise the SCO for use.
*/
public void initialise()
{
if (useCache && !SCOUtils.useCachedLazyLoading(ownerOP, ownerMmd))
{
// Load up the container now if not using lazy loading
loadFromStore();
}
}
// ----------------------- Implementation of SCO methods -------------------
/**
* Accessor for the unwrapped value that we are wrapping.
* @return The unwrapped value
*/
public java.util.SortedSet getValue()
{
loadFromStore();
return super.getValue();
}
/**
* Method to effect the load of the data in the SCO.
* Used when the SCO supports lazy-loading to tell it to load all now.
*/
public void load()
{
if (useCache)
{
loadFromStore();
}
}
/**
* Method to return if the SCO has its contents loaded.
* If the SCO doesn't support lazy loading will just return true.
* @return Whether it is loaded
*/
public boolean isLoaded()
{
return useCache ? isCacheLoaded : false;
}
/**
* Method to load all elements from the "backing store" where appropriate.
*/
protected void loadFromStore()
{
if (backingStore != null && !isCacheLoaded)
{
if (NucleusLogger.PERSISTENCE.isDebugEnabled())
{
NucleusLogger.PERSISTENCE.debug(Localiser.msg("023006",
ownerOP.getObjectAsPrintable(), ownerMmd.getName()));
}
delegate.clear();
Iterator<E> iter=backingStore.iterator(ownerOP);
while (iter.hasNext())
{
delegate.add(iter.next());
}
isCacheLoaded = true;
}
}
/* (non-Javadoc)
* @see org.datanucleus.store.types.backed.BackedSCO#getBackingStore()
*/
public Store getBackingStore()
{
return backingStore;
}
/**
* Method to update an embedded element in this collection.
* @param element The element
* @param fieldNumber Number of field in the element
* @param value New value for this field
* @param makeDirty Whether to make the SCO field dirty.
*/
public void updateEmbeddedElement(E element, int fieldNumber, Object value, boolean makeDirty)
{
if (backingStore != null)
{
backingStore.updateEmbeddedElement(ownerOP, element, fieldNumber, value);
}
}
/**
* Method to unset the owner and field information.
*/
public synchronized void unsetOwner()
{
super.unsetOwner();
if (backingStore != null)
{
backingStore = null;
}
}
// ------------------ Implementation of SortedSet methods --------------------
/**
* Creates and returns a copy of this object.
* @return The cloned object
*/
public Object clone()
{
if (useCache)
{
loadFromStore();
}
return ((java.util.TreeSet)delegate).clone();
}
/**
* Accessor for the comparator.
* @return The comparator
*/
public Comparator comparator()
{
return delegate.comparator();
}
/**
* Accessor for whether an element is contained in this Set.
* @param element The element
* @return Whether it is contained.
**/
public boolean contains(Object element)
{
if (useCache && isCacheLoaded)
{
// If the "delegate" is already loaded, use it
return delegate.contains(element);
}
else if (backingStore != null)
{
return backingStore.contains(ownerOP,element);
}
return delegate.contains(element);
}
/**
* Accessor for whether a collection is contained in this Set.
* @param c The collection
* @return Whether it is contained.
**/
public synchronized boolean containsAll(java.util.Collection c)
{
if (useCache)
{
loadFromStore();
}
else if (backingStore != null)
{
java.util.SortedSet sorted = new java.util.TreeSet(c);
Iterator iter=iterator();
while (iter.hasNext())
{
sorted.remove(iter.next());
}
return sorted.isEmpty();
}
return delegate.containsAll(c);
}
/**
* Equality operator.
* @param o The object to compare against.
* @return Whether this object is the same.
**/
public synchronized boolean equals(Object o)
{
if (useCache)
{
loadFromStore();
}
if (o == this)
{
return true;
}
if (!(o instanceof java.util.Set))
{
return false;
}
java.util.Set s = (java.util.Set)o;
return s.size() == size() && containsAll(s);
}
/**
* Accessor for the first element in the sorted set.
* @return The first element
**/
public E first()
{
if (useCache && isCacheLoaded)
{
// If the "delegate" is already loaded, use it
return delegate.first();
}
else if (useCache)
{
loadFromStore();
}
else
{
// Use Iterator to get element
Iterator<E> iter = iterator();
return iter.next();
}
return delegate.first();
}
/**
* Hashcode operator.
* @return The Hash code.
**/
public synchronized int hashCode()
{
if (useCache)
{
loadFromStore();
}
return delegate.hashCode();
}
/**
* Accessor for whether the SortedSet is empty.
* @return Whether it is empty.
**/
public boolean isEmpty()
{
return size() == 0;
}
/**
* Accessor for an iterator for the Set.
* @return The iterator
*/
public Iterator<E> iterator()
{
// Populate the cache if necessary
if (useCache)
{
loadFromStore();
}
return new SCOCollectionIterator(this, ownerOP, delegate, backingStore, useCache);
}
/**
* Method to retrieve the head elements up to the specified element.
* @param toElement the element to return up to.
* @return The set of elements meeting the input
*/
public java.util.SortedSet headSet(E toElement)
{
if (useCache && isCacheLoaded)
{
// If the "delegate" is already loaded, use it
return delegate.headSet(toElement);
}
else if (useCache)
{
loadFromStore();
}
else
{
// TODO Provide a datastore method to do this
throw new NucleusUserException("Don't currently support SortedSet.headSet() when not using cached collections");
}
return delegate.headSet(toElement);
}
/**
* Method to retrieve the subset of elements between the specified elements.
* @param fromElement The start element
* @param toElement The end element
* @return The set of elements meeting the input
*/
public java.util.SortedSet subSet(E fromElement, E toElement)
{
if (useCache && isCacheLoaded)
{
// If the "delegate" is already loaded, use it
return delegate.subSet(fromElement, toElement);
}
else if (useCache)
{
loadFromStore();
}
else
{
// TODO Provide a datastore method to do this
throw new NucleusUserException("Don't currently support SortedSet.subSet() when not using cached collections");
}
return delegate.subSet(fromElement, toElement);
}
/**
* Method to retrieve the set of elements after the specified element.
* @param fromElement The start element
* @return The set of elements meeting the input
*/
public java.util.SortedSet tailSet(E fromElement)
{
if (useCache && isCacheLoaded)
{
// If the "delegate" is already loaded, use it
return delegate.headSet(fromElement);
}
else if (useCache)
{
loadFromStore();
}
else
{
// TODO Provide a datastore method to do this
throw new NucleusUserException("Don't currently support SortedSet.tailSet() when not using cached collections");
}
return delegate.headSet(fromElement);
}
/**
* Accessor for the last element in the sorted set.
* @return The last element
**/
public E last()
{
if (useCache && isCacheLoaded)
{
// If the "delegate" is already loaded, use it
return delegate.last();
}
else if (useCache)
{
loadFromStore();
}
else
{
// Use Iterator to get element
Iterator<E> iter = iterator();
E last = null;
while (iter.hasNext())
{
last = iter.next();
}
return last;
}
return delegate.last();
}
/**
* Accessor for the size of the SortedSet.
* @return The size.
**/
public int size()
{
if (useCache && isCacheLoaded)
{
// If the "delegate" is already loaded, use it
return delegate.size();
}
else if (backingStore != null)
{
return backingStore.size(ownerOP);
}
return delegate.size();
}
/**
* Method to return the list as an array.
* @return The array
**/
public Object[] toArray()
{
if (useCache)
{
loadFromStore();
}
else if (backingStore != null)
{
return SCOUtils.toArray(backingStore,ownerOP);
}
return delegate.toArray();
}
/**
* Method to return the list as an array.
* @param a The runtime types of the array being defined by this param
* @return The array
**/
public Object[] toArray(Object a[])
{
if (useCache)
{
loadFromStore();
}
else if (backingStore != null)
{
return SCOUtils.toArray(backingStore,ownerOP,a);
}
return delegate.toArray(a);
}
// ------------------------------ Mutator methods --------------------------
/**
* Method to add an element to the SortedSet.
* @param element The new element
* @return Whether it was added ok.
**/
public boolean add(E element)
{
// Reject inappropriate elements
if (!allowNulls && element == null)
{
throw new NullPointerException("Nulls not allowed for collection at field " + ownerMmd.getName() + " but element is null");
}
if (useCache)
{
loadFromStore();
}
if (contains(element))
{
return false;
}
if (ownerOP != null && ownerOP.getExecutionContext().getManageRelations() && !initialising)
{
// Relationship management
ownerOP.getExecutionContext().getRelationshipManager(ownerOP).relationAdd(ownerMmd.getAbsoluteFieldNumber(), element);
}
boolean backingSuccess = true;
if (backingStore != null)
{
if (SCOUtils.useQueuedUpdate(ownerOP))
{
ownerOP.getExecutionContext().addOperationToQueue(new CollectionAddOperation(ownerOP, backingStore, element));
}
else
{
try
{
backingSuccess = backingStore.add(ownerOP,element, useCache ? delegate.size() : -1);
}
catch (NucleusDataStoreException dse)
{
throw new IllegalArgumentException(Localiser.msg("023013", "add", ownerMmd.getName(), dse), dse);
}
}
}
// Only make it dirty after adding the field to the datastore so we give it time
// to be inserted - otherwise jdoPreStore on this object would have been called before completing the addition
makeDirty();
boolean delegateSuccess = delegate.add(element);
if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive())
{
ownerOP.getExecutionContext().processNontransactionalUpdate();
}
return backingStore != null ? backingSuccess : delegateSuccess;
}
/**
* Method to add a collection to the SortedSet.
* @param elements The collection
* @return Whether it was added ok.
**/
public boolean addAll(Collection elements)
{
if (useCache)
{
loadFromStore();
}
if (ownerOP != null && ownerOP.getExecutionContext().getManageRelations() && !initialising)
{
// Relationship management
Iterator iter = elements.iterator();
RelationshipManager relMgr = ownerOP.getExecutionContext().getRelationshipManager(ownerOP);
while (iter.hasNext())
{
relMgr.relationAdd(ownerMmd.getAbsoluteFieldNumber(), iter.next());
}
}
boolean backingSuccess = true;
if (backingStore != null)
{
if (SCOUtils.useQueuedUpdate(ownerOP))
{
for (Object element : elements)
{
ownerOP.getExecutionContext().addOperationToQueue(new CollectionAddOperation(ownerOP, backingStore, element));
}
}
else
{
try
{
backingSuccess = backingStore.addAll(ownerOP, elements, useCache ? delegate.size() : -1);
}
catch (NucleusDataStoreException dse)
{
throw new IllegalArgumentException(Localiser.msg("023013", "addAll", ownerMmd.getName(), dse), dse);
}
}
}
// Only make it dirty after adding the field to the datastore so we give it time
// to be inserted - otherwise jdoPreStore on this object would have been called before completing the addition
makeDirty();
boolean delegateSuccess = delegate.addAll(elements);
if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive())
{
ownerOP.getExecutionContext().processNontransactionalUpdate();
}
return backingStore != null ? backingSuccess : delegateSuccess;
}
/**
* Method to clear the SortedSet
**/
public void clear()
{
makeDirty();
delegate.clear();
if (backingStore != null)
{
if (SCOUtils.useQueuedUpdate(ownerOP))
{
ownerOP.getExecutionContext().addOperationToQueue(new CollectionClearOperation(ownerOP, backingStore));
}
else
{
backingStore.clear(ownerOP);
}
}
if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive())
{
ownerOP.getExecutionContext().processNontransactionalUpdate();
}
}
/**
* Method to remove an element from the SortedSet.
* @param element The element
* @return Whether it was removed ok.
**/
public synchronized boolean remove(Object element)
{
return remove(element, true);
}
/**
* Method to remove an element from the collection, and observe the flag for whether to allow cascade delete.
* @param element The element
* @param allowCascadeDelete Whether to allow cascade delete
*/
public synchronized boolean remove(Object element, boolean allowCascadeDelete)
{
makeDirty();
if (useCache)
{
loadFromStore();
}
int size = useCache ? delegate.size() : -1;
boolean contained = delegate.contains(element);
boolean delegateSuccess = delegate.remove(element);
if (ownerOP != null && ownerOP.getExecutionContext().getManageRelations() && !initialising)
{
ownerOP.getExecutionContext().getRelationshipManager(ownerOP).relationRemove(ownerMmd.getAbsoluteFieldNumber(), element);
}
boolean backingSuccess = true;
if (backingStore != null)
{
if (SCOUtils.useQueuedUpdate(ownerOP))
{
backingSuccess = contained;
if (backingSuccess)
{
ownerOP.getExecutionContext().addOperationToQueue(new CollectionRemoveOperation(ownerOP, backingStore, element, allowCascadeDelete));
}
}
else
{
try
{
backingSuccess = backingStore.remove(ownerOP, element, size, allowCascadeDelete);
}
catch (NucleusDataStoreException dse)
{
NucleusLogger.PERSISTENCE.warn(Localiser.msg("023013", "remove", ownerMmd.getName(), dse));
backingSuccess = false;
}
}
}
if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive())
{
ownerOP.getExecutionContext().processNontransactionalUpdate();
}
return backingStore != null ? backingSuccess : delegateSuccess;
}
/**
* Method to remove all elements from the collection from the SortedSet.
* @param elements The collection of elements to remove
* @return Whether it was removed ok.
**/
public boolean removeAll(java.util.Collection elements)
{
makeDirty();
if (useCache)
{
loadFromStore();
}
int size = useCache ? delegate.size() : -1;
Collection contained = null;
if (backingStore != null && SCOUtils.useQueuedUpdate(ownerOP))
{
// Check which are contained before updating the delegate
contained = new java.util.HashSet();
for (Object elem : elements)
{
if (contains(elem))
{
contained.add(elem);
}
}
}
boolean delegateSuccess = delegate.removeAll(elements);
if (ownerOP != null && ownerOP.getExecutionContext().getManageRelations() && !initialising)
{
// Relationship management
Iterator iter = elements.iterator();
RelationshipManager relMgr = ownerOP.getExecutionContext().getRelationshipManager(ownerOP);
while (iter.hasNext())
{
relMgr.relationRemove(ownerMmd.getAbsoluteFieldNumber(), iter.next());
}
}
if (backingStore != null)
{
boolean backingSuccess = true;
if (SCOUtils.useQueuedUpdate(ownerOP))
{
backingSuccess = false;
for (Object element : contained)
{
backingSuccess = true;
ownerOP.getExecutionContext().addOperationToQueue(new CollectionRemoveOperation(ownerOP, backingStore, element, true));
}
}
else
{
try
{
backingSuccess = backingStore.removeAll(ownerOP, elements, size);
}
catch (NucleusDataStoreException dse)
{
NucleusLogger.PERSISTENCE.warn(Localiser.msg("023013", "removeAll", ownerMmd.getName(), dse));
backingSuccess = false;
}
}
if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive())
{
ownerOP.getExecutionContext().processNontransactionalUpdate();
}
return backingSuccess;
}
if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive())
{
ownerOP.getExecutionContext().processNontransactionalUpdate();
}
return delegateSuccess;
}
/**
* Method to retain a Collection of elements (and remove all others).
* @param c The collection to retain
* @return Whether they were retained successfully.
**/
public synchronized boolean retainAll(java.util.Collection c)
{
makeDirty();
if (useCache)
{
loadFromStore();
}
boolean modified = false;
Iterator iter=iterator();
while (iter.hasNext())
{
Object element = iter.next();
if (!c.contains(element))
{
iter.remove();
modified = true;
}
}
if (ownerOP != null && !ownerOP.getExecutionContext().getTransaction().isActive())
{
ownerOP.getExecutionContext().processNontransactionalUpdate();
}
return modified;
}
/**
* The writeReplace method is called when ObjectOutputStream is preparing
* to write the object to the stream. The ObjectOutputStream checks
* whether the class defines the writeReplace method. If the method is
* defined, the writeReplace method is called to allow the object to
* designate its replacement in the stream. The object returned should be
* either of the same type as the object passed in or an object that when
* read and resolved will result in an object of a type that is compatible
* with all references to the object.
*
* @return the replaced object
* @throws ObjectStreamException if an error occurs
*/
protected Object writeReplace() throws ObjectStreamException
{
if (useCache)
{
loadFromStore();
return new java.util.TreeSet(delegate);
}
// TODO Cater for non-cached collection, load elements in a DB call.
return new java.util.TreeSet(delegate);
}
@Override
public Spliterator spliterator()
{
if (backingStore != null && useCache && !isCacheLoaded)
{
loadFromStore();
}
// TODO If using backing store yet not caching, then this will fail
return delegate.spliterator();
}
@Override
public Stream stream()
{
if (backingStore != null && useCache && !isCacheLoaded)
{
loadFromStore();
}
// TODO If using backing store yet not caching, then this will fail
return delegate.stream();
}
@Override
public Stream parallelStream()
{
if (backingStore != null && useCache && !isCacheLoaded)
{
loadFromStore();
}
// TODO If using backing store yet not caching, then this will fail
return delegate.parallelStream();
}
}