001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.actions;
003
004import static org.openstreetmap.josm.tools.I18n.tr;
005
006import java.awt.Component;
007import java.awt.event.ActionEvent;
008import java.lang.ref.WeakReference;
009import java.util.ArrayList;
010import java.util.Iterator;
011import java.util.List;
012
013import org.openstreetmap.josm.Main;
014
015/**
016 * This action toggles the Expert mode.
017 * @since 4840
018 */
019public class ExpertToggleAction extends ToggleAction {
020
021    @FunctionalInterface
022    public interface ExpertModeChangeListener {
023        void expertChanged(boolean isExpert);
024    }
025
026    private static final List<WeakReference<ExpertModeChangeListener>> listeners = new ArrayList<>();
027    private static final List<WeakReference<Component>> visibilityToggleListeners = new ArrayList<>();
028
029    private static final ExpertToggleAction INSTANCE = new ExpertToggleAction();
030
031    private static synchronized void fireExpertModeChanged(boolean isExpert) {
032        Iterator<WeakReference<ExpertModeChangeListener>> it1 = listeners.iterator();
033        while (it1.hasNext()) {
034            WeakReference<ExpertModeChangeListener> wr = it1.next();
035            ExpertModeChangeListener listener = wr.get();
036            if (listener == null) {
037                it1.remove();
038                continue;
039            }
040            listener.expertChanged(isExpert);
041        }
042        Iterator<WeakReference<Component>> it2 = visibilityToggleListeners.iterator();
043        while (it2.hasNext()) {
044            WeakReference<Component> wr = it2.next();
045            Component c = wr.get();
046            if (c == null) {
047                it2.remove();
048                continue;
049            }
050            c.setVisible(isExpert);
051        }
052    }
053
054    /**
055     * Register a expert mode change listener
056     *
057     * @param listener the listener. Ignored if null.
058     */
059    public static void addExpertModeChangeListener(ExpertModeChangeListener listener) {
060        addExpertModeChangeListener(listener, false);
061    }
062
063    public static synchronized void addExpertModeChangeListener(ExpertModeChangeListener listener, boolean fireWhenAdding) {
064        if (listener == null) return;
065        for (WeakReference<ExpertModeChangeListener> wr : listeners) {
066            // already registered ? => abort
067            if (wr.get() == listener) return;
068        }
069        listeners.add(new WeakReference<>(listener));
070        if (fireWhenAdding) {
071            listener.expertChanged(isExpert());
072        }
073    }
074
075    /**
076     * Removes a expert mode change listener
077     *
078     * @param listener the listener. Ignored if null.
079     */
080    public static synchronized void removeExpertModeChangeListener(ExpertModeChangeListener listener) {
081        if (listener == null) return;
082        Iterator<WeakReference<ExpertModeChangeListener>> it = listeners.iterator();
083        while (it.hasNext()) {
084            WeakReference<ExpertModeChangeListener> wr = it.next();
085            // remove the listener - and any other listener which god garbage
086            // collected in the meantime
087            if (wr.get() == null || wr.get() == listener) {
088                it.remove();
089            }
090        }
091    }
092
093    public static synchronized void addVisibilitySwitcher(Component c) {
094        if (c == null) return;
095        for (WeakReference<Component> wr : visibilityToggleListeners) {
096            // already registered ? => abort
097            if (wr.get() == c) return;
098        }
099        visibilityToggleListeners.add(new WeakReference<>(c));
100        c.setVisible(isExpert());
101    }
102
103    public static synchronized void removeVisibilitySwitcher(Component c) {
104        if (c == null) return;
105        Iterator<WeakReference<Component>> it = visibilityToggleListeners.iterator();
106        while (it.hasNext()) {
107            WeakReference<Component> wr = it.next();
108            // remove the listener - and any other listener which god garbage
109            // collected in the meantime
110            if (wr.get() == null || wr.get() == c) {
111                it.remove();
112            }
113        }
114    }
115
116    /**
117     * Constructs a new {@code ExpertToggleAction}.
118     */
119    public ExpertToggleAction() {
120        super(tr("Expert Mode"),
121              "expert",
122              tr("Enable/disable expert mode"),
123              null,
124              false /* register toolbar */
125        );
126        putValue("toolbar", "expertmode");
127        if (Main.toolbar != null) {
128            Main.toolbar.register(this);
129        }
130        setSelected(Main.pref.getBoolean("expert", false));
131        notifySelectedState();
132    }
133
134    @Override
135    protected final void notifySelectedState() {
136        super.notifySelectedState();
137        fireExpertModeChanged(isSelected());
138    }
139
140    @Override
141    public void actionPerformed(ActionEvent e) {
142        toggleSelectedState(e);
143        Main.pref.put("expert", isSelected());
144        notifySelectedState();
145    }
146
147    /**
148     * Replies the unique instance of this action.
149     * @return The unique instance of this action
150     */
151    public static ExpertToggleAction getInstance() {
152        return INSTANCE;
153    }
154
155    /**
156     * Determines if expert mode is enabled.
157     * @return {@code true} if expert mode is enabled, {@code false} otherwise.
158     */
159    public static boolean isExpert() {
160        return INSTANCE.isSelected();
161    }
162}