1 | // License: GPL. For details, see LICENSE file.
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2 | package org.openstreetmap.josm.tools;
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3 |
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4 | import java.util.AbstractCollection;
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5 | import java.util.Iterator;
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6 | import java.util.List;
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7 |
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8 | /**
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9 | * This is a proxy of a collection that notifies a listener on every collection change
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10 | * @author Michael Zangl
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11 | *
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12 | * @param <T> The entry type
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13 | * @since 12267 (extracted from GpxData)
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14 | * @since 12156
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15 | */
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16 | public class ListeningCollection<T> extends AbstractCollection<T> {
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17 | private final List<T> base;
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18 | private final Runnable runOnModification;
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19 |
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20 | /**
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21 | * Constructs a new {@code ListeningCollection}.
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22 | * @param base base collection
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23 | * @param runOnModification runnable run at each modification
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24 | * @since 12269
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25 | */
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26 | public ListeningCollection(List<T> base, Runnable runOnModification) {
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27 | this.base = base;
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28 | this.runOnModification = runOnModification;
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29 | }
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30 |
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31 | @Override
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32 | public final Iterator<T> iterator() {
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33 | Iterator<T> it = base.iterator();
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34 | return new Iterator<T>() {
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35 | private T object;
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36 |
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37 | @Override
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38 | public boolean hasNext() {
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39 | return it.hasNext();
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40 | }
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41 |
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42 | @Override
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43 | public T next() {
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44 | object = it.next();
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45 | return object;
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46 | }
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47 |
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48 | @Override
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49 | public void remove() {
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50 | if (object != null) {
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51 | removed(object);
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52 | object = null;
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53 | }
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54 | it.remove();
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55 | }
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56 | };
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57 | }
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58 |
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59 | @Override
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60 | public final int size() {
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61 | return base.size();
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62 | }
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63 |
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64 | @Override
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65 | @SuppressWarnings("unchecked")
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66 | public final boolean remove(Object o) {
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67 | boolean remove = base.remove(o);
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68 | if (remove) {
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69 | removed((T) o);
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70 | }
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71 | return remove;
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72 | }
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73 |
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74 | @Override
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75 | public final boolean add(T e) {
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76 | boolean add = base.add(e);
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77 | added(e);
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78 | return add;
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79 | }
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80 |
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81 | /**
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82 | * Called when an object is removed.
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83 | * @param object the removed object
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84 | */
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85 | protected void removed(T object) {
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86 | runOnModification.run();
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87 | }
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88 |
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89 | /**
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90 | * Called when an object is added.
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91 | * @param object the added object
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92 | */
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93 | protected void added(T object) {
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94 | runOnModification.run();
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95 | }
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96 | }
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