* Abstract class holding various static global variables and methods used in large parts of JOSM application.

* @since 98

*/

    /**

     * The JOSM website URL.

     * @since 6897 (was public from 6143 to 6896)

     */

    private static final String JOSM_WEBSITE = "https://josm.openstreetmap.de";

    /**

     * The OSM website URL.

     * @since 6897 (was public from 6453 to 6896)

     */

    private static final String OSM_WEBSITE = "https://www.openstreetmap.org";

    /**

     * Replies true if JOSM currently displays a map view. False, if it doesn't, i.e. if

     * it only shows the MOTD panel.

     *

     * @return <code>true</code> if JOSM currently displays a map view

     */

    public static boolean isDisplayingMapView() {

        if (map == null) return false;

        if (map.mapView == null) return false;

        return true;

    }

    /**

     * Global parent component for all dialogs and message boxes

     */

    public static Component parent;

    /**

     * Global application.

     */

    public static Main main;

    /**

     * Command-line arguments used to run the application.

     */

    public static String[] commandLineArgs;

    /**

     * The worker thread slave. This is for executing all long and intensive

     * calculations. The executed runnables are guaranteed to be executed separately

     * and sequential.

     */

    public static final ExecutorService worker = new ProgressMonitorExecutor();

    /**

     * Global application preferences

     */

    public static Preferences pref;

    /**

     * The global paste buffer.

     */

    public static final PrimitiveDeepCopy pasteBuffer = new PrimitiveDeepCopy();

    /**

     * The layer source from which {@link Main#pasteBuffer} data comes from.

     */

    public static Layer pasteSource;

    /**

     * The MapFrame. Use {@link Main#setMapFrame} to set or clear it.

     */

    public static MapFrame map;

    /**

     * The toolbar preference control to register new actions.

     */

    public static ToolbarPreferences toolbar;

    /**

     * The commands undo/redo handler.

     */

    public final UndoRedoHandler undoRedo = new UndoRedoHandler();

    /**

     * The progress monitor being currently displayed.

     */

    public static PleaseWaitProgressMonitor currentProgressMonitor;

    /**

     * The main menu bar at top of screen.

     */

    public MainMenu menu;

    /**

     * The data validation handler.

     */

    public OsmValidator validator;

    /**

     * The file watcher service.

     */

    public static final FileWatcher fileWatcher = new FileWatcher();

    /**

     * The MOTD Layer.

     */

    private GettingStarted gettingStarted = new GettingStarted();

    private static final Collection<MapFrameListener> mapFrameListeners = new ArrayList<>();

    protected static final Map<String, Throwable> NETWORK_ERRORS = new HashMap<>();

    /**

     * Logging level (5 = trace, 4 = debug, 3 = info, 2 = warn, 1 = error, 0 = none).

     * @since 6248

     */

    public static int logLevel = 3;

    /**

     * Prints an error message if logging is on.

     * @param msg The message to print.

     * @since 6248

     */

    public static void error(String msg) {

        if (logLevel < 1)

            return;

        if (msg != null && !msg.isEmpty()) {

            System.err.println(tr("ERROR: {0}", msg));

        }

    }

    /**

     * Prints a warning message if logging is on.

     * @param msg The message to print.

     */

    public static void warn(String msg) {

        if (logLevel < 2)

            return;

        if (msg != null && !msg.isEmpty()) {

            System.err.println(tr("WARNING: {0}", msg));

        }

    }

    /**

     * Prints an informational message if logging is on.

     * @param msg The message to print.

     */

    public static void info(String msg) {

        if (logLevel < 3)

            return;

        if (msg != null && !msg.isEmpty()) {

            System.out.println(tr("INFO: {0}", msg));

        }

    }

    /**

     * Prints a debug message if logging is on.

     * @param msg The message to print.

     */

    public static void debug(String msg) {

        if (logLevel < 4)

            return;

        if (msg != null && !msg.isEmpty()) {

            System.out.println(tr("DEBUG: {0}", msg));

        }

    }

    /**

     * Prints a trace message if logging is on.

     * @param msg The message to print.

     */

    public static void trace(String msg) {

        if (logLevel < 5)

            return;

        if (msg != null && !msg.isEmpty()) {

            System.out.print("TRACE: ");

            System.out.println(msg);

        }

    }

    /**

     * Determines if debug log level is enabled.

     * Useful to avoid costly construction of debug messages when not enabled.

     * @return {@code true} if log level is at least debug, {@code false} otherwise

     * @since 6852

     */

    public static boolean isDebugEnabled() {

        return logLevel >= 4;

    }

    /**

     * Determines if trace log level is enabled.

     * Useful to avoid costly construction of trace messages when not enabled.

     * @return {@code true} if log level is at least trace, {@code false} otherwise

     * @since 6852

     */

    public static boolean isTraceEnabled() {

        return logLevel >= 5;

    }

    /**

     * Prints a formatted error message if logging is on. Calls {@link MessageFormat#format}

     * function to format text.

     * @param msg The formatted message to print.

     * @param objects The objects to insert into format string.

     * @since 6248

     */

    public static void error(String msg, Object... objects) {

        error(MessageFormat.format(msg, objects));

    }

    /**

     * Prints a formatted warning message if logging is on. Calls {@link MessageFormat#format}

     * function to format text.

     * @param msg The formatted message to print.

     * @param objects The objects to insert into format string.

     */

    public static void warn(String msg, Object... objects) {

        warn(MessageFormat.format(msg, objects));

    }

    /**

     * Prints a formatted informational message if logging is on. Calls {@link MessageFormat#format}

     * function to format text.

     * @param msg The formatted message to print.

     * @param objects The objects to insert into format string.

     */

    public static void info(String msg, Object... objects) {

        info(MessageFormat.format(msg, objects));

    }

    /**

     * Prints a formatted debug message if logging is on. Calls {@link MessageFormat#format}

     * function to format text.

     * @param msg The formatted message to print.

     * @param objects The objects to insert into format string.

     */

    public static void debug(String msg, Object... objects) {

        debug(MessageFormat.format(msg, objects));

    }

    /**

     * Prints an error message for the given Throwable.

     * @param t The throwable object causing the error

     * @since 6248

     */

    public static void error(Throwable t) {

        error(t, true);

    }

    /**

     * Prints a warning message for the given Throwable.

     * @param t The throwable object causing the error

     * @since 6248

     */

    public static void warn(Throwable t) {

        warn(t, true);

    }

    /**

     * Prints an error message for the given Throwable.

     * @param t The throwable object causing the error

     * @param stackTrace {@code true}, if the stacktrace should be displayed

     * @since 6642

     */

    public static void error(Throwable t, boolean stackTrace) {

        error(getErrorMessage(t));

        if (stackTrace) {

            t.printStackTrace();

        }

    }

    /**

     * Prints a warning message for the given Throwable.

     * @param t The throwable object causing the error

     * @param stackTrace {@code true}, if the stacktrace should be displayed

     * @since 6642

     */

    public static void warn(Throwable t, boolean stackTrace) {

        warn(getErrorMessage(t));

        if (stackTrace) {

            t.printStackTrace();

        }

    }

    /**

     * Returns a human-readable message of error, also usable for developers.

     * @param t The error

     * @return The human-readable error message

     * @since 6642

     */

    public static String getErrorMessage(Throwable t) {

        if (t == null) {

            return null;

        }

        StringBuilder sb = new StringBuilder(t.getClass().getName());

        String msg = t.getMessage();

        if (msg != null) {

            sb.append(": ").append(msg.trim());

        }

        Throwable cause = t.getCause();

        if (cause != null && !cause.equals(t)) {

            sb.append(". ").append(tr("Cause: ")).append(getErrorMessage(cause));

        }

        return sb.toString();

    }

    /**

     * Platform specific code goes in here.

     * Plugins may replace it, however, some hooks will be called before any plugins have been loeaded.

     * So if you need to hook into those early ones, split your class and send the one with the early hooks

     * to the JOSM team for inclusion.

     */

    public static PlatformHook platform;

    /**

     * Whether or not the java vm is openjdk

     * We use this to work around openjdk bugs

     */

    public static boolean isOpenjdk;

    /**

     * Initializes {@code Main.pref} in normal application context.

     * @since 6471

     */

    public static void initApplicationPreferences() {

        Main.pref = new Preferences();

    }

    /**

     * Set or clear (if passed <code>null</code>) the map.

     * @param map The map to set {@link Main#map} to. Can be null.

     */

    public final void setMapFrame(final MapFrame map) {

        MapFrame old = Main.map;

        panel.setVisible(false);

        panel.removeAll();

        if (map != null) {

            map.fillPanel(panel);

        } else {

            old.destroy();

            panel.add(gettingStarted, BorderLayout.CENTER);

        }

        panel.setVisible(true);

        redoUndoListener.commandChanged(0,0);

        Main.map = map;

        for (MapFrameListener listener : mapFrameListeners ) {

            listener.mapFrameInitialized(old, map);

        }

        if (map == null && currentProgressMonitor != null) {

            currentProgressMonitor.showForegroundDialog();

        }

    }

    /**

     * Remove the specified layer from the map. If it is the last layer,

     * remove the map as well.

     * @param layer The layer to remove

     */

    public final synchronized void removeLayer(final Layer layer) {

        if (map != null) {

            map.mapView.removeLayer(layer);

            if (isDisplayingMapView() && map.mapView.getAllLayers().isEmpty()) {

                setMapFrame(null);

            }

        }

    }

    private static InitStatusListener initListener = null;

    public static interface InitStatusListener {

        void updateStatus(String event);

    }

    public static void setInitStatusListener(InitStatusListener listener) {

        initListener = listener;

    }

    /**

     * Constructs new {@code Main} object. A lot of global variables are initialized here.

     */

    public Main() {

        main = this;

        isOpenjdk = System.getProperty("java.vm.name").toUpperCase().indexOf("OPENJDK") != -1;

        if (initListener != null) {

            initListener.updateStatus(tr("Executing platform startup hook"));

        }

        platform.startupHook();

        if (initListener != null) {

            initListener.updateStatus(tr("Building main menu"));

        }

        contentPanePrivate.add(panel, BorderLayout.CENTER);

        panel.add(gettingStarted, BorderLayout.CENTER);

        menu = new MainMenu();

        undoRedo.addCommandQueueListener(redoUndoListener);

        // creating toolbar

        contentPanePrivate.add(toolbar.control, BorderLayout.NORTH);

        registerActionShortcut(menu.help, Shortcut.registerShortcut("system:help", tr("Help"),

                KeyEvent.VK_F1, Shortcut.DIRECT));

        // contains several initialization tasks to be executed (in parallel) by a ExecutorService

        List<Callable<Void>> tasks = new ArrayList<>();

        tasks.add(new InitializationTask(tr("Initializing OSM API")) {

            @Override

            public void initialize() throws Exception {

                // We try to establish an API connection early, so that any API

                // capabilities are already known to the editor instance. However

                // if it goes wrong that's not critical at this stage.

                try {

                    OsmApi.getOsmApi().initialize(null, true);

                } catch (Exception e) {

                    Main.warn(getErrorMessage(Utils.getRootCause(e)));

                }

            }

        });

        tasks.add(new InitializationTask(tr("Initializing validator")) {

            @Override

            public void initialize() throws Exception {

                validator = new OsmValidator();

                MapView.addLayerChangeListener(validator);

            }

        });

        tasks.add(new InitializationTask(tr("Initializing presets")) {

            @Override

            public void initialize() throws Exception {

                TaggingPresets.initialize();

            }

        });

        tasks.add(new InitializationTask(tr("Initializing map styles")) {

            @Override

            public void initialize() throws Exception {

                MapPaintPreference.initialize();

            }

        });

        tasks.add(new InitializationTask(tr("Loading imagery preferences")) {

            @Override

            public void initialize() throws Exception {

                ImageryPreference.initialize();

            }

        });

        try {

            for (Future<Void> i : Executors.newFixedThreadPool(

                    Runtime.getRuntime().availableProcessors()).invokeAll(tasks)) {

                i.get();

            }

        } catch (Exception ex) {

            throw new RuntimeException(ex);

        }

        // hooks for the jmapviewer component

        FeatureAdapter.registerBrowserAdapter(new FeatureAdapter.BrowserAdapter() {

            @Override

            public void openLink(String url) {

                OpenBrowser.displayUrl(url);

            }

        });

        FeatureAdapter.registerTranslationAdapter(I18n.getTranslationAdapter());

        if (initListener != null) {

            initListener.updateStatus(tr("Updating user interface"));

        }

        toolbar.refreshToolbarControl();

        toolbar.control.updateUI();

        contentPanePrivate.updateUI();

    }

    private abstract class InitializationTask implements Callable<Void> {

        private final String name;

        protected InitializationTask(String name) {

            this.name = name;

        }

        public abstract void initialize() throws Exception;

        @Override

        public Void call() throws Exception {

            if (initListener != null) {

                initListener.updateStatus(name);

            }

            final long startTime = System.currentTimeMillis();

            initialize();

            if (isDebugEnabled()) {

                final long elapsedTime = System.currentTimeMillis() - startTime;

                Main.debug(tr("{0} completed in {1}", name, Utils.getDurationString(elapsedTime)));

            }

            return null;

        }

    }

    /**

     * Add a new layer to the map. If no map exists, create one.

     */

    public final synchronized void addLayer(final Layer layer) {

        boolean noMap = map == null;

        if (noMap) {

            createMapFrame(layer, null);

        }

        layer.hookUpMapView();

        map.mapView.addLayer(layer);

        if (noMap) {

            Main.map.setVisible(true);

        }

    }

    public synchronized void createMapFrame(Layer firstLayer, ViewportData viewportData) {

        MapFrame mapFrame = new MapFrame(contentPanePrivate, viewportData);

        setMapFrame(mapFrame);

        if (firstLayer != null) {

            mapFrame.selectMapMode((MapMode)mapFrame.getDefaultButtonAction(), firstLayer);

        }

        mapFrame.initializeDialogsPane();

        // bootstrapping problem: make sure the layer list dialog is going to

        // listen to change events of the very first layer

        //

        if (firstLayer != null) {

            firstLayer.addPropertyChangeListener(LayerListDialog.getInstance().getModel());

        }

    }

    /**

     * Replies <code>true</code> if there is an edit layer

     *

     * @return <code>true</code> if there is an edit layer

     */

    public boolean hasEditLayer() {

        if (getEditLayer() == null) return false;

        return true;

    }

    /**

     * Replies the current edit layer

     *

     * @return the current edit layer. <code>null</code>, if no current edit layer exists

     */

    public OsmDataLayer getEditLayer() {

        if (!isDisplayingMapView()) return null;

        return map.mapView.getEditLayer();

    }

    /**

     * Replies the current data set.

     *

     * @return the current data set. <code>null</code>, if no current data set exists

     */

    public DataSet getCurrentDataSet() {

        if (!hasEditLayer()) return null;

        return getEditLayer().data;

    }

    /**

     * Replies the current selected primitives, from a end-user point of view.

     * It is not always technically the same collection of primitives than {@link DataSet#getSelected()}.

     * Indeed, if the user is currently in drawing mode, only the way currently being drawn is returned,

     * see {@link DrawAction#getInProgressSelection()}.

     *

     * @return The current selected primitives, from a end-user point of view. Can be {@code null}.

     * @since 6546

     */

    public Collection<OsmPrimitive> getInProgressSelection() {

        if (map != null && map.mapMode instanceof DrawAction) {

            return ((DrawAction) map.mapMode).getInProgressSelection();

        } else {

            DataSet ds = getCurrentDataSet();

            if (ds == null) return null;

            return ds.getSelected();

        }

    }

    /**

     * Returns the currently active  layer

     *

     * @return the currently active layer. <code>null</code>, if currently no active layer exists

     */

    public Layer getActiveLayer() {

        if (!isDisplayingMapView()) return null;

        return map.mapView.getActiveLayer();

    }

    protected static final JPanel contentPanePrivate = new JPanel(new BorderLayout());

    public static void redirectToMainContentPane(JComponent source) {

        RedirectInputMap.redirect(source, contentPanePrivate);

    }

    public static void registerActionShortcut(JosmAction action) {

        registerActionShortcut(action, action.getShortcut());

    }

    public static void registerActionShortcut(Action action, Shortcut shortcut) {

        KeyStroke keyStroke = shortcut.getKeyStroke();

        if (keyStroke == null)

            return;

        InputMap inputMap = contentPanePrivate.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);

        Object existing = inputMap.get(keyStroke);

        if (existing != null && !existing.equals(action)) {

            info(String.format("Keystroke %s is already assigned to %s, will be overridden by %s", keyStroke, existing, action));

        }

        inputMap.put(keyStroke, action);

        contentPanePrivate.getActionMap().put(action, action);

    }

    public static void unregisterShortcut(Shortcut shortcut) {

        contentPanePrivate.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).remove(shortcut.getKeyStroke());

    }

    public static void unregisterActionShortcut(JosmAction action) {

        unregisterActionShortcut(action, action.getShortcut());

    }

    public static void unregisterActionShortcut(Action action, Shortcut shortcut) {

        unregisterShortcut(shortcut);

        contentPanePrivate.getActionMap().remove(action);

    }

    /**

     * Replies the registered action for the given shortcut

     * @param shortcut The shortcut to look for

     * @return the registered action for the given shortcut

     * @since 5696

     */

    public static Action getRegisteredActionShortcut(Shortcut shortcut) {

        KeyStroke keyStroke = shortcut.getKeyStroke();

        if (keyStroke == null)

            return null;

        Object action = contentPanePrivate.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).get(keyStroke);

        if (action instanceof Action)

            return (Action) action;

        return null;

    }

    ///////////////////////////////////////////////////////////////////////////

    //  Implementation part

    ///////////////////////////////////////////////////////////////////////////

    /**

     * Global panel.

     */

    public static final JPanel panel = new JPanel(new BorderLayout());

    protected static WindowGeometry geometry;

    protected static int windowState = JFrame.NORMAL;

    private final CommandQueueListener redoUndoListener = new CommandQueueListener(){

        @Override

        public void commandChanged(final int queueSize, final int redoSize) {

            menu.undo.setEnabled(queueSize > 0);

            menu.redo.setEnabled(redoSize > 0);

        }

    };

    /**

     * Should be called before the main constructor to setup some parameter stuff

     * @param args The parsed argument list.

     */

    public static void preConstructorInit(Map<Option, Collection<String>> args) {

        ProjectionPreference.setProjection();

        try {

            String defaultlaf = platform.getDefaultStyle();

            String laf = Main.pref.get("laf", defaultlaf);

            try {

                UIManager.setLookAndFeel(laf);

            }

            catch (final NoClassDefFoundError | ClassNotFoundException e) {

                info("Look and Feel not found: " + laf);

                Main.pref.put("laf", defaultlaf);

            }

            catch (final UnsupportedLookAndFeelException e) {

                info("Look and Feel not supported: " + laf);

                Main.pref.put("laf", defaultlaf);

            }

            toolbar = new ToolbarPreferences();

            contentPanePrivate.updateUI();

            panel.updateUI();

        } catch (final Exception e) {

            error(e);

        }

        UIManager.put("OptionPane.okIcon", ImageProvider.get("ok"));

        UIManager.put("OptionPane.yesIcon", UIManager.get("OptionPane.okIcon"));

        UIManager.put("OptionPane.cancelIcon", ImageProvider.get("cancel"));

        UIManager.put("OptionPane.noIcon", UIManager.get("OptionPane.cancelIcon"));

        I18n.translateJavaInternalMessages();

        // init default coordinate format

        //

        try {

            CoordinateFormat.setCoordinateFormat(CoordinateFormat.valueOf(Main.pref.get("coordinates")));

        } catch (IllegalArgumentException iae) {

            CoordinateFormat.setCoordinateFormat(CoordinateFormat.DECIMAL_DEGREES);

        }

        geometry = WindowGeometry.mainWindow("gui.geometry",

            (args.containsKey(Option.GEOMETRY) ? args.get(Option.GEOMETRY).iterator().next() : null),

            !args.containsKey(Option.NO_MAXIMIZE) && Main.pref.getBoolean("gui.maximized", false));

    }

    protected static void postConstructorProcessCmdLine(Map<Option, Collection<String>> args) {

        if (args.containsKey(Option.DOWNLOAD)) {

            List<File> fileList = new ArrayList<>();

            for (String s : args.get(Option.DOWNLOAD)) {

                File f = null;

                switch(paramType(s)) {

                case httpUrl:

                    downloadFromParamHttp(false, s);

                    break;

                case bounds:

                    downloadFromParamBounds(false, s);

                    break;

                case fileUrl:

                    try {

                        f = new File(new URI(s));

                    } catch (URISyntaxException e) {

                        JOptionPane.showMessageDialog(

                                Main.parent,

                                tr("Ignoring malformed file URL: \"{0}\"", s),

                                tr("Warning"),

                                JOptionPane.WARNING_MESSAGE

                                );

                    }

                    if (f!=null) {

                        fileList.add(f);

                    }

                    break;

                case fileName:

                    f = new File(s);

                    fileList.add(f);

                    break;

                }

            }

            if(!fileList.isEmpty())

            {

                OpenFileAction.openFiles(fileList, true);

            }

        }

        if (args.containsKey(Option.DOWNLOADGPS)) {

            for (String s : args.get(Option.DOWNLOADGPS)) {

                switch(paramType(s)) {

                case httpUrl:

                    downloadFromParamHttp(true, s);

                    break;

                case bounds:

                    downloadFromParamBounds(true, s);

                    break;

                case fileUrl:

                case fileName:

                    JOptionPane.showMessageDialog(

                            Main.parent,

                            tr("Parameter \"downloadgps\" does not accept file names or file URLs"),

                            tr("Warning"),

                            JOptionPane.WARNING_MESSAGE

                            );

                }

            }

        }

        if (args.containsKey(Option.SELECTION)) {

            for (String s : args.get(Option.SELECTION)) {

                SearchAction.search(s, SearchAction.SearchMode.add);

            }

        }

    }

    /**

     * Asks user to perform "save layer" operations (save on disk and/or upload data to server) for all {@link ModifiableLayer} before JOSM exits.

     * @return {@code true} if there was nothing to save, or if the user wants to proceed to save operations. {@code false} if the user cancels.

     * @since 2025

     */

    public static boolean saveUnsavedModifications() {

        if (!isDisplayingMapView()) return true;

        return saveUnsavedModifications(map.mapView.getLayersOfType(ModifiableLayer.class), true);

    }

    /**

     * Asks user to perform "save layer" operations (save on disk and/or upload data to server) before data layers deletion.

     *

     * @param selectedLayers The layers to check. Only instances of {@link ModifiableLayer} are considered.

     * @param exit {@code true} if JOSM is exiting, {@code false} otherwise.

     * @return {@code true} if there was nothing to save, or if the user wants to proceed to save operations. {@code false} if the user cancels.

     * @since 5519

     */

    public static boolean saveUnsavedModifications(Iterable<? extends Layer> selectedLayers, boolean exit) {

        SaveLayersDialog dialog = new SaveLayersDialog(parent);

        List<ModifiableLayer> layersWithUnmodifiedChanges = new ArrayList<>();

        for (Layer l: selectedLayers) {

            if (!(l instanceof ModifiableLayer)) {

                continue;

            }

            ModifiableLayer odl = (ModifiableLayer)l;

            if ((odl.requiresSaveToFile() || (odl.requiresUploadToServer() && !odl.isUploadDiscouraged())) && odl.isModified()) {

                layersWithUnmodifiedChanges.add(odl);

            }

        }

        if (exit) {

            dialog.prepareForSavingAndUpdatingLayersBeforeExit();

        } else {

            dialog.prepareForSavingAndUpdatingLayersBeforeDelete();

        }

        if (!layersWithUnmodifiedChanges.isEmpty()) {

            dialog.getModel().populate(layersWithUnmodifiedChanges);

            dialog.setVisible(true);

            switch(dialog.getUserAction()) {

            case CANCEL: return false;

            case PROCEED: return true;

            default: return false;

            }

        }

        return true;

    }

    /**

     * Closes JOSM and optionally terminates the Java Virtual Machine (JVM). If there are some unsaved data layers, asks first for user confirmation.

     * @param exit If {@code true}, the JVM is terminated by running {@link System#exit} with a given return code.

     * @param exitCode The return code

     * @return {@code true} if JOSM has been closed, {@code false} if the user has cancelled the operation.

     * @since 3378

     */

    public static boolean exitJosm(boolean exit, int exitCode) {

        if (Main.saveUnsavedModifications()) {

            geometry.remember("gui.geometry");

            if (map != null) {

                map.rememberToggleDialogWidth();

            }

            pref.put("gui.maximized", (windowState & JFrame.MAXIMIZED_BOTH) != 0);

            // Remove all layers because somebody may rely on layerRemoved events (like AutosaveTask)

            if (Main.isDisplayingMapView()) {

                Collection<Layer> layers = new ArrayList<>(Main.map.mapView.getAllLayers());

                for (Layer l: layers) {

                    Main.main.removeLayer(l);

                }

            }

            if (exit) {

                System.exit(exitCode);

            }

            return true;

        }

        return false;

    }

    /**

     * The type of a command line parameter, to be used in switch statements.

     * @see #paramType

     */

    private enum DownloadParamType { httpUrl, fileUrl, bounds, fileName }

    /**

     * Guess the type of a parameter string specified on the command line with --download= or --downloadgps.

     * @param s A parameter string

     * @return The guessed parameter type

     */

    private static DownloadParamType paramType(String s) {

        if(s.startsWith("http:") || s.startsWith("https:")) return DownloadParamType.httpUrl;

        if(s.startsWith("file:")) return DownloadParamType.fileUrl;

        String coorPattern = "\\s*[+-]?[0-9]+(\\.[0-9]+)?\\s*";

        if(s.matches(coorPattern+"(,"+coorPattern+"){3}")) return DownloadParamType.bounds;

        // everything else must be a file name

        return DownloadParamType.fileName;

    }

    /**

     * Download area specified on the command line as OSM URL.

     * @param rawGps Flag to download raw GPS tracks

     * @param s The URL parameter

     */

    private static void downloadFromParamHttp(final boolean rawGps, String s) {

        final Bounds b = OsmUrlToBounds.parse(s);

        if (b == null) {

            JOptionPane.showMessageDialog(

                    Main.parent,

                    tr("Ignoring malformed URL: \"{0}\"", s),

                    tr("Warning"),

                    JOptionPane.WARNING_MESSAGE

                    );

        } else {

            downloadFromParamBounds(rawGps, b);

        }

    }

    /**

     * Download area specified on the command line as bounds string.

     * @param rawGps Flag to download raw GPS tracks

     * @param s The bounds parameter

     */

    private static void downloadFromParamBounds(final boolean rawGps, String s) {

        final StringTokenizer st = new StringTokenizer(s, ",");

        if (st.countTokens() == 4) {

            Bounds b = new Bounds(

                    new LatLon(Double.parseDouble(st.nextToken()),Double.parseDouble(st.nextToken())),

                    new LatLon(Double.parseDouble(st.nextToken()),Double.parseDouble(st.nextToken()))

                    );

            downloadFromParamBounds(rawGps, b);

        }

    }

    /**

     * Download area specified as Bounds value.

     * @param rawGps Flag to download raw GPS tracks

     * @param b The bounds value

     * @see #downloadFromParamBounds(boolean, String)

     * @see #downloadFromParamHttp

     */

    private static void downloadFromParamBounds(final boolean rawGps, Bounds b) {

        DownloadTask task = rawGps ? new DownloadGpsTask() : new DownloadOsmTask();

        // asynchronously launch the download task ...

        Future<?> future = task.download(true, b, null);

        // ... and the continuation when the download is finished (this will wait for the download to finish)

        Main.worker.execute(new PostDownloadHandler(task, future));

    }

    /**

     * Identifies the current operating system family and initializes the platform hook accordingly.

     * @since 1849

     */

    public static void determinePlatformHook() {

        String os = System.getProperty("os.name");

        if (os == null) {

            warn("Your operating system has no name, so I'm guessing its some kind of *nix.");

            platform = new PlatformHookUnixoid();

        } else if (os.toLowerCase().startsWith("windows")) {

            platform = new PlatformHookWindows();

        } else if ("Linux".equals(os) || "Solaris".equals(os) ||

                "SunOS".equals(os) || "AIX".equals(os) ||

                "FreeBSD".equals(os) || "NetBSD".equals(os) || "OpenBSD".equals(os)) {

            platform = new PlatformHookUnixoid();

        } else if (os.toLowerCase().startsWith("mac os x")) {

            platform = new PlatformHookOsx();

        } else {

            warn("I don't know your operating system '"+os+"', so I'm guessing its some kind of *nix.");

            platform = new PlatformHookUnixoid();

        }

    }

    private static class WindowPositionSizeListener extends WindowAdapter implements

    ComponentListener {

        @Override

        public void windowStateChanged(WindowEvent e) {

            Main.windowState = e.getNewState();

        }

        @Override

        public void componentHidden(ComponentEvent e) {

        }

        @Override

        public void componentMoved(ComponentEvent e) {

            handleComponentEvent(e);

        }

        @Override

        public void componentResized(ComponentEvent e) {

            handleComponentEvent(e);

        }

        @Override

        public void componentShown(ComponentEvent e) {

        }

        private void handleComponentEvent(ComponentEvent e) {

            Component c = e.getComponent();

            if (c instanceof JFrame && c.isVisible()) {

                if(Main.windowState == JFrame.NORMAL) {

                    Main.geometry = new WindowGeometry((JFrame) c);

                } else {

                    Main.geometry.fixScreen((JFrame) c);

                }

            }

        }

    }

    protected static void addListener() {

        parent.addComponentListener(new WindowPositionSizeListener());

        ((JFrame)parent).addWindowStateListener(new WindowPositionSizeListener());

    }

    /**

     * Checks that JOSM is at least running with Java 7.

     * @since 7001

     */

    public static void checkJavaVersion() {

        String version = System.getProperty("java.version");

        if (version != null) {

            if (version.matches("^(1\\.)?[789].*"))

                return;

            if (version.matches("^(1\\.)?[56].*")) {

                JMultilineLabel ho = new JMultilineLabel("<html>"+

                        tr("<h2>JOSM requires Java version {0}.</h2>"+

                                "Detected Java version: {1}.<br>"+

                                "You can <ul><li>update your Java (JRE) or</li>"+

                                "<li>use an earlier (Java {2} compatible) version of JOSM.</li></ul>"+

                                "More Info:", "7", version, "6")+"</html>");

                JTextArea link = new JTextArea(HelpUtil.getWikiBaseHelpUrl()+"/Help/SystemRequirements");

                link.setEditable(false);

                link.setBackground(panel.getBackground());

                JPanel panel = new JPanel(new GridBagLayout());

                GridBagConstraints gbc = new GridBagConstraints();

                gbc.gridwidth = GridBagConstraints.REMAINDER;

                gbc.anchor = GridBagConstraints.WEST;

                gbc.weightx = 1.0;

                panel.add(ho, gbc);

                panel.add(link, gbc);

                final String EXIT = tr("Exit JOSM");

                final String CONTINUE = tr("Continue, try anyway");

                int ret = JOptionPane.showOptionDialog(null, panel, tr("Error"), JOptionPane.YES_NO_OPTION,

                        JOptionPane.ERROR_MESSAGE, null, new String[] {EXIT, CONTINUE}, EXIT);

                if (ret == 0) {

                    System.exit(0);

                }

                return;

            }

        }

        error("Could not recognize Java Version: "+version);

    }

    /* ----------------------------------------------------------------------------------------- */

    /* projection handling  - Main is a registry for a single, global projection instance        */

    /*                                                                                           */

    /* TODO: For historical reasons the registry is implemented by Main. An alternative approach */

    /* would be a singleton org.openstreetmap.josm.data.projection.ProjectionRegistry class.     */

    /* ----------------------------------------------------------------------------------------- */

    /**

     * The projection method used.

     * use {@link #getProjection()} and {@link #setProjection(Projection)} for access.

     * Use {@link #setProjection(Projection)} in order to trigger a projection change event.

     */

    private static Projection proj;

    /**

     * Replies the current projection.

     *

     * @return the currently active projection

     */

    public static Projection getProjection() {

        return proj;

    }

    /**

     * Sets the current projection

     *

     * @param p the projection

     */

    public static void setProjection(Projection p) {

        CheckParameterUtil.ensureParameterNotNull(p);

        Projection oldValue = proj;

        Bounds b = isDisplayingMapView() ? map.mapView.getRealBounds() : null;

        proj = p;

        fireProjectionChanged(oldValue, proj, b);

    }

    /*

     * Keep WeakReferences to the listeners. This relieves clients from the burden of

     * explicitly removing the listeners and allows us to transparently register every

     * created dataset as projection change listener.

     */

    private static final List<WeakReference<ProjectionChangeListener>> listeners = new ArrayList<>();

    private static void fireProjectionChanged(Projection oldValue, Projection newValue, Bounds oldBounds) {

        if (newValue == null ^ oldValue == null

                || (newValue != null && oldValue != null && !Objects.equals(newValue.toCode(), oldValue.toCode()))) {

            synchronized(Main.class) {

                Iterator<WeakReference<ProjectionChangeListener>> it = listeners.iterator();

                while (it.hasNext()){

                    WeakReference<ProjectionChangeListener> wr = it.next();

                    ProjectionChangeListener listener = wr.get();

                    if (listener == null) {

                        it.remove();

                        continue;

                    }

                    listener.projectionChanged(oldValue, newValue);

                }

            }

            if (newValue != null && oldBounds != null) {

                Main.map.mapView.zoomTo(oldBounds);

            }

            /* TODO - remove layers with fixed projection */

        }

    }

    /**

     * Register a projection change listener.

     *

     * @param listener the listener. Ignored if <code>null</code>.

     */

    public static void addProjectionChangeListener(ProjectionChangeListener listener) {

        if (listener == null) return;

        synchronized (Main.class) {

            for (WeakReference<ProjectionChangeListener> wr : listeners) {

                // already registered ? => abort

                if (wr.get() == listener) return;

            }

            listeners.add(new WeakReference<>(listener));

        }

    }

    /**

     * Removes a projection change listener.

     *

     * @param listener the listener. Ignored if <code>null</code>.

     */

    public static void removeProjectionChangeListener(ProjectionChangeListener listener) {

        if (listener == null) return;

        synchronized(Main.class){

            Iterator<WeakReference<ProjectionChangeListener>> it = listeners.iterator();

            while (it.hasNext()){

                WeakReference<ProjectionChangeListener> wr = it.next();

                // remove the listener - and any other listener which got garbage

                // collected in the meantime

                if (wr.get() == null || wr.get() == listener) {

                    it.remove();

                }

            }

        }

    }

    /**

     * Listener for window switch events.

     *

     * These are events, when the user activates a window of another application

     * or comes back to JOSM. Window switches from one JOSM window to another

     * are not reported.

     */

    public static interface WindowSwitchListener {

        /**

         * Called when the user activates a window of another application.

         */

        void toOtherApplication();

        /**

         * Called when the user comes from a window of another application

         * back to JOSM.

         */

        void fromOtherApplication();

    }

    private static final List<WeakReference<WindowSwitchListener>> windowSwitchListeners = new ArrayList<>();

    /**

     * Register a window switch listener.

     *

     * @param listener the listener. Ignored if <code>null</code>.

     */

    public static void addWindowSwitchListener(WindowSwitchListener listener) {

        if (listener == null) return;

        synchronized (Main.class) {

            for (WeakReference<WindowSwitchListener> wr : windowSwitchListeners) {

                // already registered ? => abort

                if (wr.get() == listener) return;

            }

            boolean wasEmpty = windowSwitchListeners.isEmpty();

            windowSwitchListeners.add(new WeakReference<>(listener));

            if (wasEmpty) {

                // The following call will have no effect, when there is no window

                // at the time. Therefore, MasterWindowListener.setup() will also be

                // called, as soon as the main window is shown.

                MasterWindowListener.setup();

            }

        }

    }

    /**

     * Removes a window switch listener.

     *

     * @param listener the listener. Ignored if <code>null</code>.

     */

    public static void removeWindowSwitchListener(WindowSwitchListener listener) {

        if (listener == null) return;

        synchronized (Main.class){

            Iterator<WeakReference<WindowSwitchListener>> it = windowSwitchListeners.iterator();

            while (it.hasNext()){

                WeakReference<WindowSwitchListener> wr = it.next();

                // remove the listener - and any other listener which got garbage

                // collected in the meantime

                if (wr.get() == null || wr.get() == listener) {

                    it.remove();

                }

            }

            if (windowSwitchListeners.isEmpty()) {

                MasterWindowListener.teardown();

            }

        }

    }

    /**

     * WindowListener, that is registered on all Windows of the application.

     *

     * Its purpose is to notify WindowSwitchListeners, that the user switches to

     * another application, e.g. a browser, or back to JOSM.

     *

     * When changing from JOSM to another application and back (e.g. two times

     * alt+tab), the active Window within JOSM may be different.

     * Therefore, we need to register listeners to <strong>all</strong> (visible)

     * Windows in JOSM, and it does not suffice to monitor the one that was

     * deactivated last.

     *

     * This class is only "active" on demand, i.e. when there is at least one

     * WindowSwitchListener registered.

     */

    protected static class MasterWindowListener extends WindowAdapter {

        private static MasterWindowListener INSTANCE;

        public static MasterWindowListener getInstance() {

            if (INSTANCE == null) {

                INSTANCE = new MasterWindowListener();

            }

            return INSTANCE;

        }

        /**

         * Register listeners to all non-hidden windows.

         *

         * Windows that are created later, will be cared for in {@link #windowDeactivated(WindowEvent)}.

         */

        public static void setup() {

            if (!windowSwitchListeners.isEmpty()) {

                for (Window w : Window.getWindows()) {

                    if (w.isShowing()) {

                        if (!Arrays.asList(w.getWindowListeners()).contains(getInstance())) {

                            w.addWindowListener(getInstance());

                        }

                    }

                }

            }

        }

        /**

         * Unregister all listeners.

         */

        public static void teardown() {

            for (Window w : Window.getWindows()) {

                w.removeWindowListener(getInstance());

            }

        }

        @Override

        public void windowActivated(WindowEvent e) {

            if (e.getOppositeWindow() == null) { // we come from a window of a different application

                // fire WindowSwitchListeners

                synchronized (Main.class) {

                    Iterator<WeakReference<WindowSwitchListener>> it = windowSwitchListeners.iterator();

                    while (it.hasNext()){

                        WeakReference<WindowSwitchListener> wr = it.next();

                        WindowSwitchListener listener = wr.get();