EventProducingList.java
package org.djutils.event.collection;
import java.rmi.RemoteException;
import java.util.Collection;
import java.util.List;
import org.djutils.event.Event;
import org.djutils.event.EventListener;
import org.djutils.event.EventType;
import org.djutils.event.LocalEventProducer;
import org.djutils.event.reference.ReferenceType;
import org.djutils.exceptions.Throw;
import org.djutils.metadata.MetaData;
import org.djutils.metadata.ObjectDescriptor;
/**
* The Event producing list provides a list to which one can subscribe interest in entry changes. This class does not keep track
* of changes which take place indirectly. One is for example not notified on <code>map.iterator.remove()</code>. A listener
* must subscribe to the iterator individually.
* <p>
* Copyright (c) 2002-2024 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
* for project information <a href="https://djutils.org" target="_blank"> https://djutils.org</a>. The DJUTILS project is
* distributed under a three-clause BSD-style license, which can be found at
* <a href="https://djutils.org/docs/license.html" target="_blank"> https://djutils.org/docs/license.html</a>. This class was
* originally part of the DSOL project, see <a href="https://simulation.tudelft.nl/dsol/manual" target="_blank">
* https://simulation.tudelft.nl/dsol/manual</a>.
* </p>
* @author <a href="https://www.linkedin.com/in/peterhmjacobs">Peter Jacobs </a>
* @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
* @param <E> the type of elements in the list
*/
public class EventProducingList<E> extends LocalEventProducer implements EventListener, List<E>
{
/** The default serial version UID for serializable classes. */
private static final long serialVersionUID = 20191230L;
/** OBJECT_ADDED_EVENT is fired on new entries. */
public static final EventType OBJECT_ADDED_EVENT =
new EventType("OBJECT_ADDED_EVENT", new MetaData("Size of the list after add", "Size of the list",
new ObjectDescriptor("Size of the list after add", "Size of the list", Integer.class)));
/** OBJECT_REMOVED_EVENT is fired on removal of entries. */
public static final EventType OBJECT_REMOVED_EVENT =
new EventType("OBJECT_REMOVED_EVENT", new MetaData("Size of the list after remove", "Size of the list",
new ObjectDescriptor("Size of the list after remove", "Size of the list", Integer.class)));
/** OBJECT_CHANGED_EVENT is fired on change of one or more entries. */
public static final EventType OBJECT_CHANGED_EVENT =
new EventType("OBJECT_CHANGED_EVENT", new MetaData("Size of the list after change", "Size of the list",
new ObjectDescriptor("Size of the list after change", "Size of the list", Integer.class)));
/** the wrapped list. */
private List<E> wrappedList = null;
/**
* constructs a new EventProducingList.
* @param wrappedList List<E>; the embedded list.
*/
public EventProducingList(final List<E> wrappedList)
{
Throw.whenNull(wrappedList, "wrappedList cannot be null");
this.wrappedList = wrappedList;
}
@Override
public int size()
{
return this.wrappedList.size();
}
@Override
public boolean isEmpty()
{
return this.wrappedList.isEmpty();
}
@Override
public void clear()
{
int nr = this.wrappedList.size();
this.wrappedList.clear();
if (nr != this.wrappedList.size())
{
fireEvent(OBJECT_REMOVED_EVENT, this.wrappedList.size());
}
}
@Override
public void add(final int index, final E element)
{
this.wrappedList.add(index, element);
fireEvent(OBJECT_ADDED_EVENT, this.wrappedList.size());
}
@Override
public boolean add(final E o)
{
boolean result = this.wrappedList.add(o);
if (result)
{
fireEvent(OBJECT_ADDED_EVENT, this.wrappedList.size());
}
return result;
}
@Override
public boolean addAll(final Collection<? extends E> c)
{
boolean result = this.wrappedList.addAll(c);
if (result)
{
fireEvent(OBJECT_ADDED_EVENT, this.wrappedList.size());
}
return result;
}
@Override
public boolean addAll(final int index, final Collection<? extends E> c)
{
boolean result = this.wrappedList.addAll(index, c);
if (result)
{
fireEvent(OBJECT_ADDED_EVENT, this.wrappedList.size());
}
return result;
}
@Override
public boolean contains(final Object o)
{
return this.wrappedList.contains(o);
}
@Override
public boolean containsAll(final Collection<?> c)
{
return this.wrappedList.containsAll(c);
}
@Override
public E get(final int index)
{
return this.wrappedList.get(index);
}
@Override
public int indexOf(final Object o)
{
return this.wrappedList.indexOf(o);
}
@Override
public EventProducingIterator<E> iterator()
{
EventProducingIterator<E> iterator = new EventProducingIterator<E>(this.wrappedList.iterator());
// WEAK reference as an iterator is usually local and should be eligible for garbage collection
iterator.addListener(this, EventProducingIterator.OBJECT_REMOVED_EVENT, ReferenceType.WEAK);
return iterator;
}
@Override
public EventProducingListIterator<E> listIterator()
{
return listIterator(0);
}
@Override
public EventProducingListIterator<E> listIterator(final int index)
{
EventProducingListIterator<E> iterator = new EventProducingListIterator<E>(this.wrappedList.listIterator(index));
// WEAK references as an iterator is usually local and should be eligible for garbage collection
iterator.addListener(this, EventProducingIterator.OBJECT_REMOVED_EVENT, ReferenceType.WEAK);
iterator.addListener(this, EventProducingListIterator.OBJECT_ADDED_EVENT, ReferenceType.WEAK);
iterator.addListener(this, EventProducingListIterator.OBJECT_CHANGED_EVENT, ReferenceType.WEAK);
return iterator;
}
@Override
public void notify(final Event event) throws RemoteException
{
// pass through the OBJECT_REMOVED_EVENT from the iterator
if (event.getType().equals(EventProducingIterator.OBJECT_REMOVED_EVENT))
{
fireEvent(OBJECT_REMOVED_EVENT, this.wrappedList.size());
}
else if (event.getType().equals(EventProducingListIterator.OBJECT_ADDED_EVENT))
{
fireEvent(OBJECT_ADDED_EVENT, this.wrappedList.size());
}
else if (event.getType().equals(EventProducingListIterator.OBJECT_CHANGED_EVENT))
{
fireEvent(OBJECT_CHANGED_EVENT, this.wrappedList.size());
}
}
@Override
public int lastIndexOf(final Object o)
{
return this.wrappedList.lastIndexOf(o);
}
@Override
public E remove(final int index)
{
E result = this.wrappedList.remove(index);
fireEvent(OBJECT_REMOVED_EVENT, this.wrappedList.size());
return result;
}
@Override
public boolean remove(final Object o)
{
boolean result = this.wrappedList.remove(o);
if (result)
{
fireEvent(OBJECT_REMOVED_EVENT, this.wrappedList.size());
}
return result;
}
@Override
public boolean removeAll(final Collection<?> c)
{
boolean result = this.wrappedList.removeAll(c);
if (result)
{
fireEvent(OBJECT_REMOVED_EVENT, this.wrappedList.size());
}
return result;
}
@Override
public boolean retainAll(final Collection<?> c)
{
boolean result = this.wrappedList.retainAll(c);
if (result)
{
fireEvent(OBJECT_REMOVED_EVENT, this.wrappedList.size());
}
return result;
}
@Override
public E set(final int index, final E element)
{
E result = this.wrappedList.set(index, element);
fireEvent(OBJECT_CHANGED_EVENT, this.wrappedList.size());
return result;
}
@Override
public List<E> subList(final int fromIndex, final int toIndex)
{
return this.wrappedList.subList(fromIndex, toIndex);
}
@Override
public Object[] toArray()
{
return this.wrappedList.toArray();
}
@Override
public <T> T[] toArray(final T[] a)
{
return this.wrappedList.toArray(a);
}
}