1 package org.djutils.event.collection;
2
3 import java.io.Serializable;
4 import java.util.Iterator;
5
6 import org.djutils.event.EventType;
7 import org.djutils.event.LocalEventProducer;
8 import org.djutils.exceptions.Throw;
9 import org.djutils.metadata.MetaData;
10
11 /**
12 * The EventProducingIterator provides an iterator embedding the Iterator, which fires an event when an object has been removed.
13 * Note that one does not have to subscribe specifically to the events of the EventProducingIterator, as the EventProducing
14 * collection subscribes to the EventProducingIterator's remove events and fires these again to its subscribers.
15 * <p>
16 * Copyright (c) 2002-2024 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
17 * for project information <a href="https://djutils.org" target="_blank"> https://djutils.org</a>. The DJUTILS project is
18 * distributed under a three-clause BSD-style license, which can be found at
19 * <a href="https://djutils.org/docs/license.html" target="_blank"> https://djutils.org/docs/license.html</a>. This class was
20 * originally part of the DSOL project, see <a href="https://simulation.tudelft.nl/dsol/manual" target="_blank">
21 * https://simulation.tudelft.nl/dsol/manual</a>.
22 * </p>
23 * @author <a href="https://www.linkedin.com/in/peterhmjacobs">Peter Jacobs </a>
24 * @author <a href="https://www.tudelft.nl/averbraeck">Alexander Verbraeck</a>
25 * @param <T> the type of elements to iterate on
26 */
27 public class EventProducingIterator<T> extends LocalEventProducer implements Iterator<T>, Serializable
28 {
29 /** The default serial version UID for serializable classes. */
30 private static final long serialVersionUID = 20191230L;
31
32 /** OBJECT_REMOVED_EVENT is fired on removal of entries. */
33 public static final EventType OBJECT_REMOVED_EVENT = new EventType("OBJECT_REMOVED_EVENT", MetaData.NO_META_DATA);
34
35 /** our parent iterator. */
36 private Iterator<T> wrappedIterator = null;
37
38 /**
39 * constructs a new EventProducingIterator, embedding the parent Iterator.
40 * @param wrappedIterator Iterator<T>; parent.
41 */
42 public EventProducingIterator(final Iterator<T> wrappedIterator)
43 {
44 Throw.whenNull(wrappedIterator, "parent cannot be null");
45 this.wrappedIterator = wrappedIterator;
46 }
47
48 @Override
49 public boolean hasNext()
50 {
51 return getWrappedIterator().hasNext();
52 }
53
54 @Override
55 public T next()
56 {
57 return getWrappedIterator().next();
58 }
59
60 @Override
61 public void remove()
62 {
63 getWrappedIterator().remove();
64 fireEvent(OBJECT_REMOVED_EVENT);
65 }
66
67 /**
68 * Return the embedded iterator.
69 * @return parent Iterator<T>; the embedded iterator
70 */
71 protected Iterator<T> getWrappedIterator()
72 {
73 return this.wrappedIterator;
74 }
75
76 }