| /* |
| * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0, |
| * or the Eclipse Distribution License v. 1.0 which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause |
| */ |
| |
| // Contributors: |
| // Oracle - initial API and implementation from Oracle TopLink |
| package org.eclipse.persistence.indirection; |
| |
| import java.beans.PropertyChangeListener; |
| import java.io.Serializable; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| import java.security.AccessController; |
| import java.security.PrivilegedActionException; |
| import java.util.Collection; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Set; |
| import java.util.Spliterator; |
| import java.util.function.Consumer; |
| import java.util.function.Predicate; |
| import java.util.stream.Stream; |
| |
| import org.eclipse.persistence.descriptors.changetracking.CollectionChangeEvent; |
| import org.eclipse.persistence.descriptors.changetracking.CollectionChangeTracker; |
| import org.eclipse.persistence.exceptions.QueryException; |
| import org.eclipse.persistence.internal.descriptors.changetracking.AttributeChangeListener; |
| import org.eclipse.persistence.internal.indirection.UnitOfWorkQueryValueHolder; |
| import org.eclipse.persistence.internal.localization.ToStringLocalization; |
| import org.eclipse.persistence.internal.security.PrivilegedAccessHelper; |
| import org.eclipse.persistence.internal.security.PrivilegedGetMethod; |
| import org.eclipse.persistence.internal.security.PrivilegedMethodInvoker; |
| import org.eclipse.persistence.mappings.DatabaseMapping; |
| |
| /** |
| * IndirectSet is an example implementation of the Set protocol that |
| * allows a domain class to take advantage of TopLink Indirection |
| * without having to declare its instance variable as a ValueHolderInterface. |
| * <p> To use an IndirectSet:<ul> |
| * <li> Declare the appropriate instance variable with type Set (or Collection). |
| * <li> Send the message #useTransparentCollection() to the appropriate |
| * CollectionMapping. |
| * <li> Send the message #useCollectionClass(IndirectSet.class) to the same |
| * CollectionMapping. (The order of these two message sends is significant.) |
| * </ul> |
| * TopLink will place an IndirectSet in the instance variable when the |
| * containing domain object is read from the database. With the first |
| * message sent to the IndirectSet, the contents |
| * are fetched from the database and normal Set behavior is resumed. |
| * |
| * <p> |
| * Implementation notes:<ul> |
| * <li> The Set interface is implemented by delegating nearly every message |
| * to the Set held on to by the 'delegate' instance variable. (The 'delegate' |
| * will be either a HashSet or yet another IndirectSet.) |
| * <li> The IndirectContainer interface is implemented in a straightforward |
| * fashion: <ul> |
| * <li> #get- and #setValueHolder() are implemented as simple accessors for the |
| * 'valueHolder' instance variable. (Note that #setValueHolder() clears out the |
| * 'delegate' instance variable, since its contents are invalidated by the arrival |
| * of a new value holder.) |
| * <li> #isInstantiated() is simply delegated to the value holder. |
| * </ul> |
| * <li> TopLink requires that the Cloneable interface be implemented. The #clone() |
| * method must clone the 'delegate'. (The implementation here uses reflection to invoke |
| * the #clone() method because it is not included in the common interface shared |
| * by IndirectSet and its base delegate class, HashSet; namely, Set.) |
| * <li> TopLink requires that the Serializable interface be implemented. |
| * <li> The database read is ultimately triggered when one of the "delegated" |
| * methods makes the first call to #getDelegate(), which in turn calls |
| * #buildDelegate(), which |
| * sends the message #getValue() to the value holder. |
| * The value holder performs the database read. |
| * <li> For debugging purposes, #toString() will <em>not</em> trigger a database |
| * read. This is not required behavior. |
| * </ul> |
| * |
| * @param <E> the type of elements maintained by this set |
| * @see org.eclipse.persistence.mappings.CollectionMapping |
| * @author Big Country |
| * @since TOPLink/Java 3.0+ |
| */ |
| public class IndirectSet<E> implements CollectionChangeTracker, Set<E>, IndirectCollection<E, Set<E>>, Cloneable, Serializable { |
| |
| /** Reduce type casting */ |
| private volatile Set<E> delegate; |
| |
| /** Delegate indirection behavior to a value holder */ |
| private volatile ValueHolderInterface<Set<E>> valueHolder; |
| |
| /** Change tracking listener. */ |
| private transient PropertyChangeListener changeListener = null; |
| |
| /** The mapping attribute name, used to raise change events. */ |
| private transient String attributeName = null; |
| |
| /** Store added elements to avoid instantiation on add. */ |
| private transient Set<E> addedElements = null; |
| |
| /** Store removed elements to avoid instantiation on remove. */ |
| private transient Set<E> removedElements = null; |
| |
| /** Store initial size for lazy init. */ |
| protected int initialCapacity = 10; |
| |
| /** Store load factor for lazy init. */ |
| protected float loadFactor = 0.75f; |
| |
| /** |
| * This value is used to determine if we should attempt to do adds and removes from the list without |
| * actually instantiating the list from the database. By default, this is set to false. When set to |
| * true, adding duplicate elements to the set will result in the element being added when the transaction |
| * is committed. |
| */ |
| private boolean useLazyInstantiation = false; |
| |
| /** |
| * Construct an empty IndirectSet. |
| */ |
| public IndirectSet() { |
| this.delegate = null; |
| this.valueHolder = null; |
| } |
| |
| /** |
| * Construct an empty IndirectSet with the specified initial capacity. |
| * |
| * @param initialCapacity the initial capacity of the set |
| * @exception IllegalArgumentException if the specified initial capacity |
| * is negative |
| */ |
| public IndirectSet(int initialCapacity) { |
| this.delegate = null; |
| this.initialCapacity = initialCapacity; |
| this.valueHolder = null; |
| } |
| |
| /** |
| * Construct an empty IndirectSet with the specified initial capacity and |
| * load factor. |
| * |
| * @param initialCapacity the initial capacity of the set |
| * @param loadFactor the load factor of the set |
| * @exception IllegalArgumentException if the specified initial capacity |
| * is negative |
| */ |
| public IndirectSet(int initialCapacity, float loadFactor) { |
| this.delegate = null; |
| this.initialCapacity = initialCapacity; |
| this.loadFactor = loadFactor; |
| this.valueHolder = null; |
| } |
| |
| /** |
| * Construct an IndirectSet containing the elements of the specified collection. |
| * |
| * @param c the initial elements of the set |
| */ |
| public IndirectSet(Collection<? extends E> c) { |
| this.delegate = null; |
| this.valueHolder = new ValueHolder<>(new HashSet<>(c)); |
| } |
| |
| protected boolean isRelationshipMaintenanceRequired() { |
| if (this.valueHolder instanceof UnitOfWorkQueryValueHolder) { |
| DatabaseMapping mapping = ((UnitOfWorkQueryValueHolder)this.valueHolder).getMapping(); |
| return (mapping != null) && (mapping.getRelationshipPartner() != null); |
| } |
| return false; |
| } |
| |
| /** |
| * @see java.util.Set#add(java.lang.Object) |
| */ |
| @Override |
| public boolean add(E element) { |
| boolean added = true; |
| // PERF: If not instantiated just record the add to avoid the instantiation. |
| if (shouldAvoidInstantiation()) { |
| if (hasRemovedElements() && getRemovedElements().contains(element)) { |
| getRemovedElements().remove(element); |
| } else if (isRelationshipMaintenanceRequired() && getAddedElements().contains(element)) { |
| // Must avoid recursion for relationship maintenance. |
| return false; |
| } else { |
| getAddedElements().add(element); |
| } |
| } else { |
| added = getDelegate().add(element); |
| } |
| if (added) { |
| raiseAddChangeEvent(element); |
| } |
| return added; |
| } |
| |
| /** |
| * @see java.util.Set#addAll(java.util.Collection) |
| */ |
| @Override |
| public boolean addAll(Collection<? extends E> c) { |
| // Must trigger add events if tracked or uow. |
| if (hasBeenRegistered() || hasTrackedPropertyChangeListener()) { |
| Iterator<? extends E> objects = c.iterator(); |
| while (objects.hasNext()) { |
| this.add(objects.next()); |
| } |
| return true; |
| } |
| |
| return getDelegate().addAll(c); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the freshly-built delegate. |
| */ |
| protected Set<E> buildDelegate() { |
| Set<E> newDelegate = getValueHolder().getValue(); |
| if (newDelegate == null) { |
| newDelegate = new HashSet<>(this.initialCapacity, this.loadFactor); |
| } |
| // This can either be another indirect set or a HashSet. |
| // It can be another indirect list because the mapping's query uses the same container policy. |
| // Unwrap any redundant indirection layers, which can cause issues and impact performance. |
| while (newDelegate instanceof IndirectSet) { |
| newDelegate = ((IndirectSet) newDelegate).getDelegate(); |
| } |
| // First add/remove any cached changes. |
| if (hasAddedElements()) { |
| for (Iterator<E> iterator = getAddedElements().iterator(); iterator.hasNext(); ) { |
| newDelegate.add(iterator.next()); |
| } |
| this.addedElements = null; |
| } |
| if (hasRemovedElements()) { |
| for (Iterator<E> iterator = getRemovedElements().iterator(); iterator.hasNext(); ) { |
| newDelegate.remove(iterator.next()); |
| } |
| this.removedElements = null; |
| } |
| return newDelegate; |
| } |
| |
| /** |
| * @see java.util.Set#clear() |
| */ |
| @Override |
| public void clear() { |
| if (hasBeenRegistered() || hasTrackedPropertyChangeListener()) { |
| Iterator<E> objects = iterator(); |
| while (objects.hasNext()) { |
| objects.next(); |
| objects.remove(); |
| } |
| // clear delegate in case it's still not empty, see bug 338393 |
| } |
| getDelegate().clear(); |
| } |
| |
| /** |
| * INTERNAL: |
| * clear any changes that have been deferred to instantiation. |
| * Indirect collections with change tracking avoid instantiation on add/remove. |
| */ |
| @Override |
| public void clearDeferredChanges(){ |
| addedElements = null; |
| removedElements = null; |
| } |
| |
| /** |
| * @see java.lang.Object#clone() |
| * This will result in a database query if necessary. |
| */ |
| |
| /* |
| There are 3 situations when #clone() is called: |
| 1. The developer actually wants to clone the collection (typically to modify one |
| of the 2 resulting collections). In which case the contents must be read from |
| the database. |
| 2. A UnitOfWork needs a clone (or backup clone) of the collection. But the |
| UnitOfWork checks "instantiation" before cloning collections (i.e. "un-instantiated" |
| collections are not cloned). |
| 3. A MergeManager needs an extra copy of the collection (because the "backup" |
| and "target" are the same object?). But the MergeManager also checks "instantiation" |
| before merging collections (again, "un-instantiated" collections are not merged). |
| */ |
| @Override |
| public Object clone() { |
| try { |
| IndirectSet<E> result = (IndirectSet<E>)super.clone(); |
| result.delegate = this.cloneDelegate(); |
| result.valueHolder = new ValueHolder<>(result.delegate); |
| result.attributeName = null; |
| result.changeListener = null; |
| return result; |
| } catch (CloneNotSupportedException e) { |
| throw new InternalError("clone not supported"); |
| } |
| } |
| |
| /** |
| * INTERNAL: |
| * Clone the delegate. |
| */ |
| protected Set<E> cloneDelegate() { |
| Method cloneMethod; |
| try { |
| if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){ |
| try { |
| cloneMethod = AccessController.doPrivileged(new PrivilegedGetMethod(this.getDelegate().getClass(), "clone", null, false)); |
| } catch (PrivilegedActionException exception) { |
| throw QueryException.cloneMethodRequired(); |
| } |
| } else { |
| cloneMethod = PrivilegedAccessHelper.getMethod(this.getDelegate().getClass(), "clone", null, false); |
| } |
| } catch (NoSuchMethodException ex) { |
| throw QueryException.cloneMethodRequired(); |
| } |
| |
| try { |
| if (PrivilegedAccessHelper.shouldUsePrivilegedAccess()){ |
| try { |
| return (Set<E>)AccessController.doPrivileged(new PrivilegedMethodInvoker(cloneMethod, this.getDelegate(), null)); |
| } catch (PrivilegedActionException exception) { |
| Exception throwableException = exception.getException(); |
| if (throwableException instanceof IllegalAccessException) { |
| throw QueryException.cloneMethodInaccessible(); |
| } else if (throwableException instanceof InvocationTargetException) { |
| throw QueryException.cloneMethodThrowException(((InvocationTargetException)throwableException).getTargetException()); |
| } else { |
| throw QueryException.cloneMethodThrowException(throwableException); |
| } |
| } |
| } else { |
| return (Set<E>)PrivilegedAccessHelper.invokeMethod(cloneMethod, this.getDelegate(), null); |
| } |
| } catch (IllegalAccessException ex1) { |
| throw QueryException.cloneMethodInaccessible(); |
| } catch (InvocationTargetException ex2) { |
| throw QueryException.cloneMethodThrowException(ex2.getTargetException()); |
| } |
| } |
| |
| /** |
| * @see java.util.Set#contains(java.lang.Object) |
| */ |
| @Override |
| public boolean contains(Object element) { |
| // PERF: Avoid instantiation if not required. |
| if (hasAddedElements()) { |
| if (getAddedElements().contains(element)) { |
| return true; |
| } |
| } |
| if (hasRemovedElements()) { |
| if (getRemovedElements().contains(element)) { |
| return false; |
| } |
| } |
| return this.getDelegate().contains(element); |
| } |
| |
| /** |
| * @see java.util.Set#containsAll(java.util.Collection) |
| */ |
| @Override |
| public boolean containsAll(Collection<?> c) { |
| return this.getDelegate().containsAll(c); |
| } |
| |
| /** |
| * @see java.util.Set#equals(java.lang.Object) |
| */ |
| @Override |
| public boolean equals(Object o) { |
| return this.getDelegate().equals(o); |
| } |
| |
| @Override |
| public Spliterator<E> spliterator() { |
| return getDelegate().spliterator(); |
| } |
| |
| @Override |
| public Stream<E> parallelStream() { |
| return getDelegate().parallelStream(); |
| } |
| |
| @Override |
| public Stream<E> stream() { |
| return getDelegate().stream(); |
| } |
| |
| @Override |
| public boolean removeIf(Predicate<? super E> filter) { |
| // Must trigger remove events if tracked or uow. |
| if (hasBeenRegistered() || hasTrackedPropertyChangeListener()) { |
| boolean hasChanged = false; |
| Iterator<E> objects = iterator(); |
| while (objects.hasNext()) { |
| if (filter.test(objects.next())) { |
| objects.remove(); |
| hasChanged |= true; |
| } |
| } |
| return hasChanged; |
| } |
| return getDelegate().removeIf(filter); |
| } |
| |
| @Override |
| public void forEach(Consumer<? super E> action) { |
| getDelegate().forEach(action); |
| } |
| |
| /** |
| * INTERNAL: |
| * Check whether the contents have been read from the database. |
| * If they have not, read them and set the delegate. |
| */ |
| protected Set<E> getDelegate() { |
| Set<E> newDelegate = this.delegate; |
| if (newDelegate == null) { |
| synchronized(this){ |
| newDelegate = this.delegate; |
| if (newDelegate == null) { |
| this.delegate = newDelegate = this.buildDelegate(); |
| } |
| } |
| } |
| return newDelegate; |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the real collection object. |
| * This will force instantiation. |
| */ |
| @Override |
| public Set<E> getDelegateObject() { |
| return getDelegate(); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the valueHolder. |
| */ |
| @Override |
| public ValueHolderInterface<Set<E>> getValueHolder() { |
| |
| ValueHolderInterface<Set<E>> vh = this.valueHolder; |
| // PERF: lazy initialize value holder and vector as are normally set after creation. |
| if (vh == null) { |
| synchronized(this){ |
| vh = this.valueHolder; |
| if (vh == null) { |
| this.valueHolder = vh = new ValueHolder<>(new HashSet<>(initialCapacity, loadFactor)); |
| } |
| } |
| } |
| return vh; |
| } |
| |
| /** |
| * INTERNAL: |
| * Return whether this IndirectSet has been registered in a UnitOfWork |
| */ |
| public boolean hasBeenRegistered() { |
| return getValueHolder() instanceof org.eclipse.persistence.internal.indirection.UnitOfWorkQueryValueHolder; |
| } |
| |
| /** |
| * @see java.util.Set#hashCode() |
| */ |
| @Override |
| public int hashCode() { |
| return this.getDelegate().hashCode(); |
| } |
| |
| /** |
| * @see java.util.Set#isEmpty() |
| */ |
| @Override |
| public boolean isEmpty() { |
| return this.getDelegate().isEmpty(); |
| } |
| |
| /** |
| * Return whether the contents have been read from the database. |
| */ |
| @Override |
| public boolean isInstantiated() { |
| return this.getValueHolder().isInstantiated(); |
| } |
| |
| /** |
| * @see java.util.Set#iterator() |
| */ |
| @Override |
| public Iterator<E> iterator() { |
| // Must wrap the interator to raise the remove event. |
| return new Iterator<E>() { |
| Iterator<E> delegateIterator = IndirectSet.this.getDelegate().iterator(); |
| E currentObject; |
| |
| @Override |
| public boolean hasNext() { |
| return this.delegateIterator.hasNext(); |
| } |
| |
| @Override |
| public E next() { |
| this.currentObject = this.delegateIterator.next(); |
| return this.currentObject; |
| } |
| |
| @Override |
| public void remove() { |
| this.delegateIterator.remove(); |
| IndirectSet.this.raiseRemoveChangeEvent(this.currentObject); |
| } |
| |
| @Override |
| public void forEachRemaining(Consumer<? super E> action) { |
| this.delegateIterator.forEachRemaining(action); |
| } |
| }; |
| } |
| |
| /** |
| * @see java.util.Set#remove(java.lang.Object) |
| */ |
| @Override |
| public boolean remove(Object element) { |
| // PERF: If not instantiated just record the removal to avoid the instantiation. |
| if (shouldAvoidInstantiation()) { |
| if (hasAddedElements() && getAddedElements().contains(element)) { |
| getAddedElements().remove(element); |
| } else if (getRemovedElements().contains(element)) { |
| // Must avoid recursion for relationship maintenance. |
| return false; |
| } else { |
| getRemovedElements().add((E) element); |
| } |
| this.raiseRemoveChangeEvent(element); |
| return true; |
| } else if (this.getDelegate().remove(element)) { |
| this.raiseRemoveChangeEvent(element); |
| return true; |
| } |
| return false; |
| } |
| |
| /** |
| * @see java.util.Set#removeAll(java.util.Collection) |
| */ |
| @Override |
| public boolean removeAll(Collection<?> c) { |
| // Must trigger remove events if tracked or uow. |
| if (hasBeenRegistered() || hasTrackedPropertyChangeListener()) { |
| Iterator objects = c.iterator(); |
| while (objects.hasNext()) { |
| this.remove(objects.next()); |
| } |
| return true; |
| } |
| return this.getDelegate().removeAll(c); |
| } |
| |
| /** |
| * @see java.util.Set#retainAll(java.util.Collection) |
| */ |
| @Override |
| public boolean retainAll(Collection<?> c) { |
| // Must trigger remove events if tracked or uow. |
| if (hasBeenRegistered() || hasTrackedPropertyChangeListener()) { |
| Iterator objects = getDelegate().iterator(); |
| while (objects.hasNext()) { |
| Object object = objects.next(); |
| if (!c.contains(object)) { |
| objects.remove(); |
| this.raiseRemoveChangeEvent(object); |
| } |
| } |
| return true; |
| } |
| return this.getDelegate().retainAll(c); |
| } |
| |
| /** |
| * INTERNAL: |
| * Set the value holder. |
| * Note that the delegate must be cleared out. |
| */ |
| @Override |
| public void setValueHolder(ValueHolderInterface<Set<E>> valueHolder) { |
| this.delegate = null; |
| this.valueHolder = valueHolder; |
| } |
| |
| /** |
| * INTERNAL |
| * Set whether this collection should attempt do deal with adds and removes without retrieving the |
| * collection from the dB |
| */ |
| @Override |
| public void setUseLazyInstantiation(boolean useLazyInstantiation){ |
| this.useLazyInstantiation = useLazyInstantiation; |
| } |
| |
| /** |
| * @see java.util.Set#size() |
| */ |
| @Override |
| public int size() { |
| return this.getDelegate().size(); |
| } |
| |
| /** |
| * Return whether this collection should attempt do deal with adds and removes without retrieving the |
| * collection from the dB |
| */ |
| protected boolean shouldUseLazyInstantiation(){ |
| return useLazyInstantiation; |
| } |
| |
| /** |
| * @see java.util.Set#toArray() |
| */ |
| @Override |
| public Object[] toArray() { |
| return this.getDelegate().toArray(); |
| } |
| |
| /** |
| * @see java.util.Set#toArray(java.lang.Object[]) |
| */ |
| @Override |
| public <T> T[] toArray(T[] a) { |
| return this.getDelegate().toArray(a); |
| } |
| |
| /** |
| * Use the delegate's #toString(); but wrap it with braces to indicate |
| * there is a bit of indirection. |
| * Don't allow this method to trigger a database read. |
| * @see java.util.HashSet#toString() |
| */ |
| @Override |
| public String toString() { |
| if (ValueHolderInterface.shouldToStringInstantiate) { |
| return this.getDelegate().toString(); |
| } |
| if (this.isInstantiated()) { |
| return "{" + this.getDelegate().toString() + "}"; |
| } else { |
| return "{" + org.eclipse.persistence.internal.helper.Helper.getShortClassName(this.getClass()) + ": " + ToStringLocalization.buildMessage("not_instantiated", null) + "}"; |
| |
| } |
| } |
| |
| /** |
| * Raise the add change event and relationship maintainence. |
| */ |
| protected void raiseAddChangeEvent(Object element) { |
| if (hasTrackedPropertyChangeListener()) { |
| _persistence_getPropertyChangeListener().propertyChange(new CollectionChangeEvent(this, getTrackedAttributeName(), this, element, CollectionChangeEvent.ADD, true)); |
| } |
| if (isRelationshipMaintenanceRequired()) { |
| ((UnitOfWorkQueryValueHolder)getValueHolder()).updateForeignReferenceSet(element, null); |
| } |
| } |
| |
| /** |
| * Raise the remove change event. |
| */ |
| protected void raiseRemoveChangeEvent(Object element) { |
| if (hasTrackedPropertyChangeListener()) { |
| _persistence_getPropertyChangeListener().propertyChange(new CollectionChangeEvent(this, getTrackedAttributeName(), this, element, CollectionChangeEvent.REMOVE, true)); |
| } |
| if (isRelationshipMaintenanceRequired()) { |
| ((UnitOfWorkQueryValueHolder)getValueHolder()).updateForeignReferenceRemove(element); |
| } |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the property change listener for change tracking. |
| */ |
| @Override |
| public PropertyChangeListener _persistence_getPropertyChangeListener() { |
| return changeListener; |
| } |
| |
| /** |
| * INTERNAL: |
| * Return if the collection has a property change listener for change tracking. |
| */ |
| public boolean hasTrackedPropertyChangeListener() { |
| return this.changeListener != null; |
| } |
| |
| /** |
| * INTERNAL: |
| * Set the property change listener for change tracking. |
| */ |
| @Override |
| public void _persistence_setPropertyChangeListener(PropertyChangeListener changeListener) { |
| this.changeListener = changeListener; |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the mapping attribute name, used to raise change events. |
| */ |
| @Override |
| public String getTrackedAttributeName() { |
| return attributeName; |
| } |
| |
| /** |
| * INTERNAL: |
| * Set the mapping attribute name, used to raise change events. |
| * This is required if the change listener is set. |
| */ |
| @Override |
| public void setTrackedAttributeName(String attributeName) { |
| this.attributeName = attributeName; |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the elements that have been removed before instantiation. |
| */ |
| @Override |
| public Collection<E> getRemovedElements() { |
| if (removedElements == null) { |
| removedElements = new HashSet<>(); |
| } |
| return removedElements; |
| } |
| |
| /** |
| * INTERNAL: |
| * Return the elements that have been added before instantiation. |
| */ |
| @Override |
| public Collection<E> getAddedElements() { |
| if (addedElements == null) { |
| addedElements = new HashSet<>(); |
| } |
| return addedElements; |
| } |
| |
| /** |
| * INTERNAL: |
| * Return if any elements that have been added before instantiation. |
| */ |
| public boolean hasAddedElements() { |
| return (addedElements != null) && (!addedElements.isEmpty()); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return if any elements that have been removed before instantiation. |
| */ |
| public boolean hasRemovedElements() { |
| return (removedElements != null) && (!removedElements.isEmpty()); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return if any elements that have been added or removed before instantiation. |
| */ |
| @Override |
| public boolean hasDeferredChanges() { |
| return hasRemovedElements() || hasAddedElements(); |
| } |
| |
| /** |
| * INTERNAL: |
| * Return if add/remove should trigger instantiation or avoid. |
| * Current instantiation is avoided is using change tracking. |
| */ |
| protected boolean shouldAvoidInstantiation() { |
| return (!isInstantiated()) && (shouldUseLazyInstantiation()) && (_persistence_getPropertyChangeListener() instanceof AttributeChangeListener) && ((WeavedAttributeValueHolderInterface)getValueHolder()).shouldAllowInstantiationDeferral(); |
| } |
| } |
