[315] | 1 | package org.apollo.mvc;
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| 2 |
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| 3 | import java.util.HashSet;
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| 4 | import java.util.Set;
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| 5 |
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| 6 | import javax.swing.SwingUtilities;
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| 7 |
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| 8 | /**
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| 9 | * A Skeletal implementation of a Subject in the model-view-controller package.
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| 10 | *
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| 11 | * @author Brook Novak
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| 12 | */
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| 13 | public abstract class AbstractSubject implements Subject {
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| 14 |
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| 15 | /** Collection of registered observers. */
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| 16 | protected Set<Observer> observers = new HashSet <Observer>();
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| 17 |
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| 18 | /**
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| 19 | * Adds an observer to the set of registered observers.
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| 20 | * @param ob The observer to add.
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| 21 | */
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| 22 | public final void addObserver(final Observer ob) {
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| 23 | synchronized (observers) {
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| 24 | observers.add(ob);
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| 25 | }
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| 26 | ob.setObservedSubject(this);
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| 27 | }
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| 28 |
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| 29 | /**
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| 30 | * Removes an observer from the set of registered observers.
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| 31 | *
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| 32 | * @param ob The observer to remove
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| 33 | */
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| 34 | public final void removeObserver(final Observer ob) {
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| 35 | synchronized (observers) {
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| 36 | observers.remove(ob);
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| 37 | }
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| 38 | ob.setObservedSubject(null);
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| 39 | }
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| 40 |
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| 41 | /**
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| 42 | * Notifies all observers that this object has changed with the given
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| 43 | * ModelChangeEvent.
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| 44 | *
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| 45 | * @param event
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| 46 | * A ModelChangeEvent which specifies how this object has
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| 47 | * changed.
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| 48 | */
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| 49 | protected final void fireSubjectChanged(final SubjectChangedEvent event) {
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| 50 |
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| 51 | synchronized (observers) {
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| 52 | for (Observer ob : observers) {
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| 53 | ob.modelChanged(this, event);
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| 54 | }
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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 | * Notifies all observers that this object has changed with the given
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| 60 | * ModelChangeEvent. On the swing thread.
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| 61 | *
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| 62 | * @param event
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| 63 | * A ModelChangeEvent which specifies how this object has
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| 64 | * changed.
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| 65 | */
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| 66 | protected final void fireSubjectChangedLaterOnSwingThread(final SubjectChangedEvent event) {
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| 67 |
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| 68 | SwingUtilities.invokeLater(new Runnable() {
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| 69 | public void run() {
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| 70 | fireSubjectChanged(event);
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| 71 | }
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| 72 | });
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| 73 |
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| 74 | }
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| 75 |
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| 76 | }
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