001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.actions.mapmode;
003
004import static org.openstreetmap.josm.gui.help.HelpUtil.ht;
005import static org.openstreetmap.josm.tools.I18n.tr;
006import static org.openstreetmap.josm.tools.I18n.trn;
007
008import java.awt.Cursor;
009import java.awt.Point;
010import java.awt.Rectangle;
011import java.awt.event.KeyEvent;
012import java.awt.event.MouseEvent;
013import java.awt.geom.Point2D;
014import java.util.Collection;
015import java.util.Collections;
016import java.util.HashSet;
017import java.util.Iterator;
018import java.util.LinkedList;
019import java.util.Set;
020
021import javax.swing.JOptionPane;
022
023import org.openstreetmap.josm.Main;
024import org.openstreetmap.josm.actions.MergeNodesAction;
025import org.openstreetmap.josm.command.AddCommand;
026import org.openstreetmap.josm.command.ChangeCommand;
027import org.openstreetmap.josm.command.Command;
028import org.openstreetmap.josm.command.MoveCommand;
029import org.openstreetmap.josm.command.RotateCommand;
030import org.openstreetmap.josm.command.ScaleCommand;
031import org.openstreetmap.josm.command.SequenceCommand;
032import org.openstreetmap.josm.data.coor.EastNorth;
033import org.openstreetmap.josm.data.coor.LatLon;
034import org.openstreetmap.josm.data.osm.DataSet;
035import org.openstreetmap.josm.data.osm.Node;
036import org.openstreetmap.josm.data.osm.OsmPrimitive;
037import org.openstreetmap.josm.data.osm.Way;
038import org.openstreetmap.josm.data.osm.WaySegment;
039import org.openstreetmap.josm.data.osm.visitor.AllNodesVisitor;
040import org.openstreetmap.josm.data.osm.visitor.paint.WireframeMapRenderer;
041import org.openstreetmap.josm.gui.ExtendedDialog;
042import org.openstreetmap.josm.gui.MapFrame;
043import org.openstreetmap.josm.gui.MapView;
044import org.openstreetmap.josm.gui.MapViewState.MapViewPoint;
045import org.openstreetmap.josm.gui.SelectionManager;
046import org.openstreetmap.josm.gui.SelectionManager.SelectionEnded;
047import org.openstreetmap.josm.gui.layer.Layer;
048import org.openstreetmap.josm.gui.layer.OsmDataLayer;
049import org.openstreetmap.josm.gui.util.GuiHelper;
050import org.openstreetmap.josm.gui.util.KeyPressReleaseListener;
051import org.openstreetmap.josm.gui.util.ModifierListener;
052import org.openstreetmap.josm.tools.ImageProvider;
053import org.openstreetmap.josm.tools.Pair;
054import org.openstreetmap.josm.tools.Shortcut;
055import org.openstreetmap.josm.tools.Utils;
056
057/**
058 * Move is an action that can move all kind of OsmPrimitives (except keys for now).
059 *
060 * If an selected object is under the mouse when dragging, move all selected objects.
061 * If an unselected object is under the mouse when dragging, it becomes selected
062 * and will be moved.
063 * If no object is under the mouse, move all selected objects (if any)
064 *
065 * On Mac OS X, Ctrl + mouse button 1 simulates right click (map move), so the
066 * feature "selection remove" is disabled on this platform.
067 */
068public class SelectAction extends MapMode implements ModifierListener, KeyPressReleaseListener, SelectionEnded {
069
070    /**
071     * Select action mode.
072     * @since 7543
073     */
074    public enum Mode {
075        /** "MOVE" means either dragging or select if no mouse movement occurs (i.e. just clicking) */
076        MOVE,
077        /** "ROTATE" allows to apply a rotation transformation on the selected object (see {@link RotateCommand}) */
078        ROTATE,
079        /** "SCALE" allows to apply a scaling transformation on the selected object (see {@link ScaleCommand}) */
080        SCALE,
081        /** "SELECT" means the selection rectangle */
082        SELECT
083    }
084
085    // contains all possible cases the cursor can be in the SelectAction
086    private enum SelectActionCursor {
087        rect("normal", /* ICON(cursor/modifier/) */ "selection"),
088        rect_add("normal", /* ICON(cursor/modifier/) */ "select_add"),
089        rect_rm("normal", /* ICON(cursor/modifier/) */ "select_remove"),
090        way("normal", /* ICON(cursor/modifier/) */ "select_way"),
091        way_add("normal", /* ICON(cursor/modifier/) */ "select_way_add"),
092        way_rm("normal", /* ICON(cursor/modifier/) */ "select_way_remove"),
093        node("normal", /* ICON(cursor/modifier/) */ "select_node"),
094        node_add("normal", /* ICON(cursor/modifier/) */ "select_node_add"),
095        node_rm("normal", /* ICON(cursor/modifier/) */ "select_node_remove"),
096        virtual_node("normal", /* ICON(cursor/modifier/) */ "addnode"),
097        scale(/* ICON(cursor/) */ "scale", null),
098        rotate(/* ICON(cursor/) */ "rotate", null),
099        merge(/* ICON(cursor/) */ "crosshair", null),
100        lasso("normal", /* ICON(cursor/modifier/) */ "rope"),
101        merge_to_node("crosshair", /* ICON(cursor/modifier/) */ "joinnode"),
102        move(Cursor.MOVE_CURSOR);
103
104        private final Cursor c;
105        SelectActionCursor(String main, String sub) {
106            c = ImageProvider.getCursor(main, sub);
107        }
108
109        SelectActionCursor(int systemCursor) {
110            c = Cursor.getPredefinedCursor(systemCursor);
111        }
112
113        public Cursor cursor() {
114            return c;
115        }
116    }
117
118    private boolean lassoMode;
119    public boolean repeatedKeySwitchLassoOption;
120
121    // Cache previous mouse event (needed when only the modifier keys are
122    // pressed but the mouse isn't moved)
123    private MouseEvent oldEvent;
124
125    private Mode mode;
126    private final transient SelectionManager selectionManager;
127    private boolean cancelDrawMode;
128    private boolean drawTargetHighlight;
129    private boolean didMouseDrag;
130    /**
131     * The component this SelectAction is associated with.
132     */
133    private final MapView mv;
134    /**
135     * The old cursor before the user pressed the mouse button.
136     */
137    private Point startingDraggingPos;
138    /**
139     * point where user pressed the mouse to start movement
140     */
141    private EastNorth startEN;
142    /**
143     * The last known position of the mouse.
144     */
145    private Point lastMousePos;
146    /**
147     * The time of the user mouse down event.
148     */
149    private long mouseDownTime;
150    /**
151     * The pressed button of the user mouse down event.
152     */
153    private int mouseDownButton;
154    /**
155     * The time of the user mouse down event.
156     */
157    private long mouseReleaseTime;
158    /**
159     * The time which needs to pass between click and release before something
160     * counts as a move, in milliseconds
161     */
162    private int initialMoveDelay;
163    /**
164     * The screen distance which needs to be travelled before something
165     * counts as a move, in pixels
166     */
167    private int initialMoveThreshold;
168    private boolean initialMoveThresholdExceeded;
169
170    /**
171     * elements that have been highlighted in the previous iteration. Used
172     * to remove the highlight from them again as otherwise the whole data
173     * set would have to be checked.
174     */
175    private transient Set<OsmPrimitive> oldHighlights = new HashSet<>();
176
177    /**
178     * Create a new SelectAction
179     * @param mapFrame The MapFrame this action belongs to.
180     */
181    public SelectAction(MapFrame mapFrame) {
182        super(tr("Select"), "move/move", tr("Select, move, scale and rotate objects"),
183                Shortcut.registerShortcut("mapmode:select", tr("Mode: {0}", tr("Select")), KeyEvent.VK_S, Shortcut.DIRECT),
184                mapFrame,
185                ImageProvider.getCursor("normal", "selection"));
186        mv = mapFrame.mapView;
187        putValue("help", ht("/Action/Select"));
188        selectionManager = new SelectionManager(this, false, mv);
189    }
190
191    @Override
192    public void enterMode() {
193        super.enterMode();
194        mv.addMouseListener(this);
195        mv.addMouseMotionListener(this);
196        mv.setVirtualNodesEnabled(Main.pref.getInteger("mappaint.node.virtual-size", 8) != 0);
197        drawTargetHighlight = Main.pref.getBoolean("draw.target-highlight", true);
198        initialMoveDelay = Main.pref.getInteger("edit.initial-move-delay", 200);
199        initialMoveThreshold = Main.pref.getInteger("edit.initial-move-threshold", 5);
200        repeatedKeySwitchLassoOption = Main.pref.getBoolean("mappaint.select.toggle-lasso-on-repeated-S", true);
201        cycleManager.init();
202        virtualManager.init();
203        // This is required to update the cursors when ctrl/shift/alt is pressed
204        Main.map.keyDetector.addModifierListener(this);
205        Main.map.keyDetector.addKeyListener(this);
206    }
207
208    @Override
209    public void exitMode() {
210        super.exitMode();
211        selectionManager.unregister(mv);
212        mv.removeMouseListener(this);
213        mv.removeMouseMotionListener(this);
214        mv.setVirtualNodesEnabled(false);
215        Main.map.keyDetector.removeModifierListener(this);
216        Main.map.keyDetector.removeKeyListener(this);
217        removeHighlighting();
218    }
219
220    @Override
221    public void modifiersChanged(int modifiers) {
222        if (!Main.isDisplayingMapView() || oldEvent == null) return;
223        if (giveUserFeedback(oldEvent, modifiers)) {
224            mv.repaint();
225        }
226    }
227
228    /**
229     * handles adding highlights and updating the cursor for the given mouse event.
230     * Please note that the highlighting for merging while moving is handled via mouseDragged.
231     * @param e {@code MouseEvent} which should be used as base for the feedback
232     * @return {@code true} if repaint is required
233     */
234    private boolean giveUserFeedback(MouseEvent e) {
235        return giveUserFeedback(e, e.getModifiers());
236    }
237
238    /**
239     * handles adding highlights and updating the cursor for the given mouse event.
240     * Please note that the highlighting for merging while moving is handled via mouseDragged.
241     * @param e {@code MouseEvent} which should be used as base for the feedback
242     * @param modifiers define custom keyboard modifiers if the ones from MouseEvent are outdated or similar
243     * @return {@code true} if repaint is required
244     */
245    private boolean giveUserFeedback(MouseEvent e, int modifiers) {
246        Collection<OsmPrimitive> c = asColl(
247                mv.getNearestNodeOrWay(e.getPoint(), mv.isSelectablePredicate, true));
248
249        updateKeyModifiers(modifiers);
250        determineMapMode(!c.isEmpty());
251
252        Set<OsmPrimitive> newHighlights = new HashSet<>();
253
254        virtualManager.clear();
255        if (mode == Mode.MOVE && !dragInProgress() && virtualManager.activateVirtualNodeNearPoint(e.getPoint())) {
256            DataSet ds = getLayerManager().getEditDataSet();
257            if (ds != null && drawTargetHighlight) {
258                ds.setHighlightedVirtualNodes(virtualManager.virtualWays);
259            }
260            mv.setNewCursor(SelectActionCursor.virtual_node.cursor(), this);
261            // don't highlight anything else if a virtual node will be
262            return repaintIfRequired(newHighlights);
263        }
264
265        mv.setNewCursor(getCursor(c), this);
266
267        // return early if there can't be any highlights
268        if (!drawTargetHighlight || mode != Mode.MOVE || c.isEmpty())
269            return repaintIfRequired(newHighlights);
270
271        // CTRL toggles selection, but if while dragging CTRL means merge
272        final boolean isToggleMode = ctrl && !dragInProgress();
273        for (OsmPrimitive x : c) {
274            // only highlight primitives that will change the selection
275            // when clicked. I.e. don't highlight selected elements unless
276            // we are in toggle mode.
277            if (isToggleMode || !x.isSelected()) {
278                newHighlights.add(x);
279            }
280        }
281        return repaintIfRequired(newHighlights);
282    }
283
284    /**
285     * works out which cursor should be displayed for most of SelectAction's
286     * features. The only exception is the "move" cursor when actually dragging
287     * primitives.
288     * @param nearbyStuff  primitives near the cursor
289     * @return the cursor that should be displayed
290     */
291    private Cursor getCursor(Collection<OsmPrimitive> nearbyStuff) {
292        String c = "rect";
293        switch(mode) {
294        case MOVE:
295            if (virtualManager.hasVirtualNode()) {
296                c = "virtual_node";
297                break;
298            }
299            final Iterator<OsmPrimitive> it = nearbyStuff.iterator();
300            final OsmPrimitive osm = it.hasNext() ? it.next() : null;
301
302            if (dragInProgress()) {
303                // only consider merge if ctrl is pressed and there are nodes in
304                // the selection that could be merged
305                if (!ctrl || getLayerManager().getEditDataSet().getSelectedNodes().isEmpty()) {
306                    c = "move";
307                    break;
308                }
309                // only show merge to node cursor if nearby node and that node is currently
310                // not being dragged
311                final boolean hasTarget = osm instanceof Node && !osm.isSelected();
312                c = hasTarget ? "merge_to_node" : "merge";
313                break;
314            }
315
316            c = (osm instanceof Node) ? "node" : c;
317            c = (osm instanceof Way) ? "way" : c;
318            if (shift) {
319                c += "_add";
320            } else if (ctrl) {
321                c += osm == null || osm.isSelected() ? "_rm" : "_add";
322            }
323            break;
324        case ROTATE:
325            c = "rotate";
326            break;
327        case SCALE:
328            c = "scale";
329            break;
330        case SELECT:
331            if (lassoMode) {
332                c = "lasso";
333            } else {
334                c = "rect" + (shift ? "_add" : (ctrl && !Main.isPlatformOsx() ? "_rm" : ""));
335            }
336            break;
337        }
338        return SelectActionCursor.valueOf(c).cursor();
339    }
340
341    /**
342     * Removes all existing highlights.
343     * @return true if a repaint is required
344     */
345    private boolean removeHighlighting() {
346        boolean needsRepaint = false;
347        DataSet ds = getLayerManager().getEditDataSet();
348        if (ds != null && !ds.getHighlightedVirtualNodes().isEmpty()) {
349            needsRepaint = true;
350            ds.clearHighlightedVirtualNodes();
351        }
352        if (oldHighlights.isEmpty())
353            return needsRepaint;
354
355        for (OsmPrimitive prim : oldHighlights) {
356            prim.setHighlighted(false);
357        }
358        oldHighlights = new HashSet<>();
359        return true;
360    }
361
362    private boolean repaintIfRequired(Set<OsmPrimitive> newHighlights) {
363        if (!drawTargetHighlight)
364            return false;
365
366        boolean needsRepaint = false;
367        for (OsmPrimitive x : newHighlights) {
368            if (oldHighlights.contains(x)) {
369                continue;
370            }
371            needsRepaint = true;
372            x.setHighlighted(true);
373        }
374        oldHighlights.removeAll(newHighlights);
375        for (OsmPrimitive x : oldHighlights) {
376            x.setHighlighted(false);
377            needsRepaint = true;
378        }
379        oldHighlights = newHighlights;
380        return needsRepaint;
381    }
382
383    /**
384     * Look, whether any object is selected. If not, select the nearest node.
385     * If there are no nodes in the dataset, do nothing.
386     *
387     * If the user did not press the left mouse button, do nothing.
388     *
389     * Also remember the starting position of the movement and change the mouse
390     * cursor to movement.
391     */
392    @Override
393    public void mousePressed(MouseEvent e) {
394        mouseDownButton = e.getButton();
395        // return early
396        if (!mv.isActiveLayerVisible() || !(Boolean) this.getValue("active") || mouseDownButton != MouseEvent.BUTTON1)
397            return;
398
399        // left-button mouse click only is processed here
400
401        // request focus in order to enable the expected keyboard shortcuts
402        mv.requestFocus();
403
404        // update which modifiers are pressed (shift, alt, ctrl)
405        updateKeyModifiers(e);
406
407        // We don't want to change to draw tool if the user tries to (de)select
408        // stuff but accidentally clicks in an empty area when selection is empty
409        cancelDrawMode = shift || ctrl;
410        didMouseDrag = false;
411        initialMoveThresholdExceeded = false;
412        mouseDownTime = System.currentTimeMillis();
413        lastMousePos = e.getPoint();
414        startEN = mv.getEastNorth(lastMousePos.x, lastMousePos.y);
415
416        // primitives under cursor are stored in c collection
417
418        OsmPrimitive nearestPrimitive = mv.getNearestNodeOrWay(e.getPoint(), mv.isSelectablePredicate, true);
419
420        determineMapMode(nearestPrimitive != null);
421
422        switch(mode) {
423        case ROTATE:
424        case SCALE:
425            //  if nothing was selected, select primitive under cursor for scaling or rotating
426            DataSet ds = getLayerManager().getEditDataSet();
427            if (ds.selectionEmpty()) {
428                ds.setSelected(asColl(nearestPrimitive));
429            }
430
431            // Mode.select redraws when selectPrims is called
432            // Mode.move   redraws when mouseDragged is called
433            // Mode.rotate redraws here
434            // Mode.scale redraws here
435            break;
436        case MOVE:
437            // also include case when some primitive is under cursor and no shift+ctrl / alt+ctrl is pressed
438            // so this is not movement, but selection on primitive under cursor
439            if (!cancelDrawMode && nearestPrimitive instanceof Way) {
440                virtualManager.activateVirtualNodeNearPoint(e.getPoint());
441            }
442            OsmPrimitive toSelect = cycleManager.cycleSetup(nearestPrimitive, e.getPoint());
443            selectPrims(asColl(toSelect), false, false);
444            useLastMoveCommandIfPossible();
445            // Schedule a timer to update status line "initialMoveDelay+1" ms in the future
446            GuiHelper.scheduleTimer(initialMoveDelay+1, evt -> updateStatusLine(), false);
447            break;
448        case SELECT:
449        default:
450            if (!(ctrl && Main.isPlatformOsx())) {
451                // start working with rectangle or lasso
452                selectionManager.register(mv, lassoMode);
453                selectionManager.mousePressed(e);
454                break;
455            }
456        }
457        if (giveUserFeedback(e)) {
458            mv.repaint();
459        }
460        updateStatusLine();
461    }
462
463    @Override
464    public void mouseMoved(MouseEvent e) {
465        // Mac OSX simulates with ctrl + mouse 1 the second mouse button hence no dragging events get fired.
466        if (Main.isPlatformOsx() && (mode == Mode.ROTATE || mode == Mode.SCALE)) {
467            mouseDragged(e);
468            return;
469        }
470        oldEvent = e;
471        if (giveUserFeedback(e)) {
472            mv.repaint();
473        }
474    }
475
476    /**
477     * If the left mouse button is pressed, move all currently selected
478     * objects (if one of them is under the mouse) or the current one under the
479     * mouse (which will become selected).
480     */
481    @Override
482    public void mouseDragged(MouseEvent e) {
483        if (!mv.isActiveLayerVisible())
484            return;
485
486        // Swing sends random mouseDragged events when closing dialogs by double-clicking their top-left icon on Windows
487        // Ignore such false events to prevent issues like #7078
488        if (mouseDownButton == MouseEvent.BUTTON1 && mouseReleaseTime > mouseDownTime)
489            return;
490
491        cancelDrawMode = true;
492        if (mode == Mode.SELECT) {
493            // Unregisters selectionManager if ctrl has been pressed after mouse click on Mac OS X in order to move the map
494            if (ctrl && Main.isPlatformOsx()) {
495                selectionManager.unregister(mv);
496                // Make sure correct cursor is displayed
497                mv.setNewCursor(Cursor.MOVE_CURSOR, this);
498            }
499            return;
500        }
501
502        // do not count anything as a move if it lasts less than 100 milliseconds.
503        if ((mode == Mode.MOVE) && (System.currentTimeMillis() - mouseDownTime < initialMoveDelay))
504            return;
505
506        if (mode != Mode.ROTATE && mode != Mode.SCALE && (e.getModifiersEx() & MouseEvent.BUTTON1_DOWN_MASK) == 0) {
507            // button is pressed in rotate mode
508            return;
509        }
510
511        if (mode == Mode.MOVE) {
512            // If ctrl is pressed we are in merge mode. Look for a nearby node,
513            // highlight it and adjust the cursor accordingly.
514            final boolean canMerge = ctrl && !getLayerManager().getEditDataSet().getSelectedNodes().isEmpty();
515            final OsmPrimitive p = canMerge ? findNodeToMergeTo(e.getPoint()) : null;
516            boolean needsRepaint = removeHighlighting();
517            if (p != null) {
518                p.setHighlighted(true);
519                oldHighlights.add(p);
520                needsRepaint = true;
521            }
522            mv.setNewCursor(getCursor(asColl(p)), this);
523            // also update the stored mouse event, so we can display the correct cursor
524            // when dragging a node onto another one and then press CTRL to merge
525            oldEvent = e;
526            if (needsRepaint) {
527                mv.repaint();
528            }
529        }
530
531        if (startingDraggingPos == null) {
532            startingDraggingPos = new Point(e.getX(), e.getY());
533        }
534
535        if (lastMousePos == null) {
536            lastMousePos = e.getPoint();
537            return;
538        }
539
540        if (!initialMoveThresholdExceeded) {
541            int dp = (int) lastMousePos.distance(e.getX(), e.getY());
542            if (dp < initialMoveThreshold)
543                return; // ignore small drags
544            initialMoveThresholdExceeded = true; //no more ingnoring uintil nex mouse press
545        }
546        if (e.getPoint().equals(lastMousePos))
547            return;
548
549        EastNorth currentEN = mv.getEastNorth(e.getX(), e.getY());
550
551        if (virtualManager.hasVirtualWaysToBeConstructed()) {
552            virtualManager.createMiddleNodeFromVirtual(currentEN);
553        } else {
554            if (!updateCommandWhileDragging(currentEN)) return;
555        }
556
557        mv.repaint();
558        if (mode != Mode.SCALE) {
559            lastMousePos = e.getPoint();
560        }
561
562        didMouseDrag = true;
563    }
564
565    @Override
566    public void mouseExited(MouseEvent e) {
567        if (removeHighlighting()) {
568            mv.repaint();
569        }
570    }
571
572    @Override
573    public void mouseReleased(MouseEvent e) {
574        if (!mv.isActiveLayerVisible())
575            return;
576
577        startingDraggingPos = null;
578        mouseReleaseTime = System.currentTimeMillis();
579
580        if (mode == Mode.SELECT) {
581            if (e.getButton() != MouseEvent.BUTTON1) {
582                return;
583            }
584            selectionManager.endSelecting(e);
585            selectionManager.unregister(mv);
586
587            // Select Draw Tool if no selection has been made
588            if (getLayerManager().getEditDataSet().selectionEmpty() && !cancelDrawMode) {
589                Main.map.selectDrawTool(true);
590                updateStatusLine();
591                return;
592            }
593        }
594
595        if (mode == Mode.MOVE && e.getButton() == MouseEvent.BUTTON1) {
596            if (!didMouseDrag) {
597                // only built in move mode
598                virtualManager.clear();
599                // do nothing if the click was to short too be recognized as a drag,
600                // but the release position is farther than 10px away from the press position
601                if (lastMousePos == null || lastMousePos.distanceSq(e.getPoint()) < 100) {
602                    updateKeyModifiers(e);
603                    selectPrims(cycleManager.cyclePrims(), true, false);
604
605                    // If the user double-clicked a node, change to draw mode
606                    Collection<OsmPrimitive> c = getLayerManager().getEditDataSet().getSelected();
607                    if (e.getClickCount() >= 2 && c.size() == 1 && c.iterator().next() instanceof Node) {
608                        // We need to do it like this as otherwise drawAction will see a double
609                        // click and switch back to SelectMode
610                        Main.worker.execute(() -> Main.map.selectDrawTool(true));
611                        return;
612                    }
613                }
614            } else {
615                confirmOrUndoMovement(e);
616            }
617        }
618
619        mode = null;
620
621        // simply remove any highlights if the middle click popup is active because
622        // the highlights don't depend on the cursor position there. If something was
623        // selected beforehand this would put us into move mode as well, which breaks
624        // the cycling through primitives on top of each other (see #6739).
625        if (e.getButton() == MouseEvent.BUTTON2) {
626            removeHighlighting();
627        } else {
628            giveUserFeedback(e);
629        }
630        updateStatusLine();
631    }
632
633    @Override
634    public void selectionEnded(Rectangle r, MouseEvent e) {
635        updateKeyModifiers(e);
636        selectPrims(selectionManager.getSelectedObjects(alt), true, true);
637    }
638
639    @Override
640    public void doKeyPressed(KeyEvent e) {
641        if (!Main.isDisplayingMapView() ||
642                !repeatedKeySwitchLassoOption || !getShortcut().isEvent(e)) return;
643        if (Main.isDebugEnabled()) {
644            Main.debug(getClass().getName()+" consuming event "+e);
645        }
646        e.consume();
647        if (!lassoMode) {
648            Main.map.selectMapMode(Main.map.mapModeSelectLasso);
649        } else {
650            Main.map.selectMapMode(Main.map.mapModeSelect);
651        }
652    }
653
654    @Override
655    public void doKeyReleased(KeyEvent e) {
656        // Do nothing
657    }
658
659    /**
660     * sets the mapmode according to key modifiers and if there are any
661     * selectables nearby. Everything has to be pre-determined for this
662     * function; its main purpose is to centralize what the modifiers do.
663     * @param hasSelectionNearby {@code true} if some primitves are selectable nearby
664     */
665    private void determineMapMode(boolean hasSelectionNearby) {
666        if (shift && ctrl) {
667            mode = Mode.ROTATE;
668        } else if (alt && ctrl) {
669            mode = Mode.SCALE;
670        } else if (hasSelectionNearby || dragInProgress()) {
671            mode = Mode.MOVE;
672        } else {
673            mode = Mode.SELECT;
674        }
675    }
676
677    /**
678     * Determines whenever elements have been grabbed and moved (i.e. the initial
679     * thresholds have been exceeded) and is still in progress (i.e. mouse button still pressed)
680     * @return true if a drag is in progress
681     */
682    private boolean dragInProgress() {
683        return didMouseDrag && startingDraggingPos != null;
684    }
685
686    /**
687     * Create or update data modification command while dragging mouse - implementation of
688     * continuous moving, scaling and rotation
689     * @param currentEN - mouse position
690     * @return status of action (<code>true</code> when action was performed)
691     */
692    private boolean updateCommandWhileDragging(EastNorth currentEN) {
693        // Currently we support only transformations which do not affect relations.
694        // So don't add them in the first place to make handling easier
695        DataSet ds = getLayerManager().getEditDataSet();
696        Collection<OsmPrimitive> selection = ds.getSelectedNodesAndWays();
697        if (selection.isEmpty()) { // if nothing was selected to drag, just select nearest node/way to the cursor
698            OsmPrimitive nearestPrimitive = mv.getNearestNodeOrWay(mv.getPoint(startEN), mv.isSelectablePredicate, true);
699            ds.setSelected(nearestPrimitive);
700        }
701
702        Collection<Node> affectedNodes = AllNodesVisitor.getAllNodes(selection);
703        // for these transformations, having only one node makes no sense - quit silently
704        if (affectedNodes.size() < 2 && (mode == Mode.ROTATE || mode == Mode.SCALE)) {
705            return false;
706        }
707        Command c = getLastCommand();
708        if (mode == Mode.MOVE) {
709            if (startEN == null) return false; // fix #8128
710            ds.beginUpdate();
711            if (c instanceof MoveCommand && affectedNodes.equals(((MoveCommand) c).getParticipatingPrimitives())) {
712                ((MoveCommand) c).saveCheckpoint();
713                ((MoveCommand) c).applyVectorTo(currentEN);
714            } else {
715                c = new MoveCommand(selection, startEN, currentEN);
716                Main.main.undoRedo.add(c);
717            }
718            for (Node n : affectedNodes) {
719                LatLon ll = n.getCoor();
720                if (ll != null && ll.isOutSideWorld()) {
721                    // Revert move
722                    ((MoveCommand) c).resetToCheckpoint();
723                    ds.endUpdate();
724                    JOptionPane.showMessageDialog(
725                            Main.parent,
726                            tr("Cannot move objects outside of the world."),
727                            tr("Warning"),
728                            JOptionPane.WARNING_MESSAGE);
729                    mv.setNewCursor(cursor, this);
730                    return false;
731                }
732            }
733        } else {
734            startEN = currentEN; // drag can continue after scaling/rotation
735
736            if (mode != Mode.ROTATE && mode != Mode.SCALE) {
737                return false;
738            }
739
740            ds.beginUpdate();
741
742            if (mode == Mode.ROTATE) {
743                if (c instanceof RotateCommand && affectedNodes.equals(((RotateCommand) c).getTransformedNodes())) {
744                    ((RotateCommand) c).handleEvent(currentEN);
745                } else {
746                    Main.main.undoRedo.add(new RotateCommand(selection, currentEN));
747                }
748            } else if (mode == Mode.SCALE) {
749                if (c instanceof ScaleCommand && affectedNodes.equals(((ScaleCommand) c).getTransformedNodes())) {
750                    ((ScaleCommand) c).handleEvent(currentEN);
751                } else {
752                    Main.main.undoRedo.add(new ScaleCommand(selection, currentEN));
753                }
754            }
755
756            Collection<Way> ways = ds.getSelectedWays();
757            if (doesImpactStatusLine(affectedNodes, ways)) {
758                Main.map.statusLine.setDist(ways);
759            }
760        }
761        ds.endUpdate();
762        return true;
763    }
764
765    private static boolean doesImpactStatusLine(Collection<Node> affectedNodes, Collection<Way> selectedWays) {
766        for (Way w : selectedWays) {
767            for (Node n : w.getNodes()) {
768                if (affectedNodes.contains(n)) {
769                    return true;
770                }
771            }
772        }
773        return false;
774    }
775
776    /**
777     * Adapt last move command (if it is suitable) to work with next drag, started at point startEN
778     */
779    private void useLastMoveCommandIfPossible() {
780        Command c = getLastCommand();
781        Collection<Node> affectedNodes = AllNodesVisitor.getAllNodes(getLayerManager().getEditDataSet().getSelected());
782        if (c instanceof MoveCommand && affectedNodes.equals(((MoveCommand) c).getParticipatingPrimitives())) {
783            // old command was created with different base point of movement, we need to recalculate it
784            ((MoveCommand) c).changeStartPoint(startEN);
785        }
786    }
787
788    /**
789     * Obtain command in undoRedo stack to "continue" when dragging
790     * @return last command
791     */
792    private static Command getLastCommand() {
793        Command c = !Main.main.undoRedo.commands.isEmpty()
794                ? Main.main.undoRedo.commands.getLast() : null;
795        if (c instanceof SequenceCommand) {
796            c = ((SequenceCommand) c).getLastCommand();
797        }
798        return c;
799    }
800
801    /**
802     * Present warning in the following cases and undo unwanted movements: <ul>
803     * <li>large and possibly unwanted movements</li>
804     * <li>movement of node with attached ways that are hidden by filters</li>
805     * </ul>
806     *
807     * @param e the mouse event causing the action (mouse released)
808     */
809    private void confirmOrUndoMovement(MouseEvent e) {
810        if (movesHiddenWay()) {
811            final ExtendedDialog ed = new ConfirmMoveDialog();
812            ed.setContent(tr("Are you sure that you want to move elements with attached ways that are hidden by filters?"));
813            ed.toggleEnable("movedHiddenElements");
814            ed.showDialog();
815            if (ed.getValue() != 1) {
816                Main.main.undoRedo.undo();
817            }
818        }
819        int max = Main.pref.getInteger("warn.move.maxelements", 20), limit = max;
820        for (OsmPrimitive osm : getLayerManager().getEditDataSet().getSelected()) {
821            if (osm instanceof Way) {
822                limit -= ((Way) osm).getNodes().size();
823            }
824            if (--limit < 0) {
825                break;
826            }
827        }
828        if (limit < 0) {
829            final ExtendedDialog ed = new ConfirmMoveDialog();
830            ed.setContent(
831                    /* for correct i18n of plural forms - see #9110 */
832                    trn("You moved more than {0} element. " + "Moving a large number of elements is often an error.\n" + "Really move them?",
833                        "You moved more than {0} elements. " + "Moving a large number of elements is often an error.\n" + "Really move them?",
834                        max, max));
835            ed.toggleEnable("movedManyElements");
836            ed.showDialog();
837
838            if (ed.getValue() != 1) {
839                Main.main.undoRedo.undo();
840            }
841        } else {
842            // if small number of elements were moved,
843            updateKeyModifiers(e);
844            if (ctrl) mergePrims(e.getPoint());
845        }
846        getLayerManager().getEditDataSet().fireSelectionChanged();
847    }
848
849    static class ConfirmMoveDialog extends ExtendedDialog {
850        ConfirmMoveDialog() {
851            super(Main.parent,
852                    tr("Move elements"),
853                    new String[]{tr("Move them"), tr("Undo move")});
854            setButtonIcons(new String[]{"reorder", "cancel"});
855            setCancelButton(2);
856        }
857    }
858
859    private boolean movesHiddenWay() {
860        DataSet ds = getLayerManager().getEditDataSet();
861        final Collection<OsmPrimitive> elementsToTest = new HashSet<>(ds.getSelected());
862        for (Way osm : Utils.filteredCollection(ds.getSelected(), Way.class)) {
863            elementsToTest.addAll(osm.getNodes());
864        }
865        for (OsmPrimitive node : Utils.filteredCollection(elementsToTest, Node.class)) {
866            for (Way ref : Utils.filteredCollection(node.getReferrers(), Way.class)) {
867                if (ref.isDisabledAndHidden()) {
868                    return true;
869                }
870            }
871        }
872        return false;
873    }
874
875    /**
876     * Merges the selected nodes to the one closest to the given mouse position if the control
877     * key is pressed. If there is no such node, no action will be done and no error will be
878     * reported. If there is, it will execute the merge and add it to the undo buffer.
879     * @param p mouse position
880     */
881    private void mergePrims(Point p) {
882        DataSet ds = getLayerManager().getEditDataSet();
883        Collection<Node> selNodes = ds.getSelectedNodes();
884        if (selNodes.isEmpty())
885            return;
886
887        Node target = findNodeToMergeTo(p);
888        if (target == null)
889            return;
890
891        if (selNodes.size() == 1) {
892            // Move all selected primitive to preserve shape #10748
893            Collection<OsmPrimitive> selection = ds.getSelectedNodesAndWays();
894            Collection<Node> affectedNodes = AllNodesVisitor.getAllNodes(selection);
895            Command c = getLastCommand();
896            ds.beginUpdate();
897            if (c instanceof MoveCommand
898                && affectedNodes.equals(((MoveCommand) c).getParticipatingPrimitives())) {
899                Node selectedNode = selNodes.iterator().next();
900                EastNorth selectedEN = selectedNode.getEastNorth();
901                EastNorth targetEN = target.getEastNorth();
902                ((MoveCommand) c).moveAgain(targetEN.getX() - selectedEN.getX(),
903                                            targetEN.getY() - selectedEN.getY());
904            }
905            ds.endUpdate();
906        }
907
908        Collection<Node> nodesToMerge = new LinkedList<>(selNodes);
909        nodesToMerge.add(target);
910        mergeNodes(Main.getLayerManager().getEditLayer(), nodesToMerge, target);
911    }
912
913    /**
914     * Merge nodes using {@code MergeNodesAction}.
915     * Can be overridden for testing purpose.
916     * @param layer layer the reference data layer. Must not be null
917     * @param nodes the collection of nodes. Ignored if null
918     * @param targetLocationNode this node's location will be used for the target node
919     */
920    public void mergeNodes(OsmDataLayer layer, Collection<Node> nodes,
921                           Node targetLocationNode) {
922        MergeNodesAction.doMergeNodes(layer, nodes, targetLocationNode);
923    }
924
925    /**
926     * Tries to find a node to merge to when in move-merge mode for the current mouse
927     * position. Either returns the node or null, if no suitable one is nearby.
928     * @param p mouse position
929     * @return node to merge to, or null
930     */
931    private Node findNodeToMergeTo(Point p) {
932        Collection<Node> target = mv.getNearestNodes(p,
933                getLayerManager().getEditDataSet().getSelectedNodes(),
934                mv.isSelectablePredicate);
935        return target.isEmpty() ? null : target.iterator().next();
936    }
937
938    private void selectPrims(Collection<OsmPrimitive> prims, boolean released, boolean area) {
939        DataSet ds = getLayerManager().getEditDataSet();
940
941        // not allowed together: do not change dataset selection, return early
942        // Virtual Ways: if non-empty the cursor is above a virtual node. So don't highlight
943        // anything if about to drag the virtual node (i.e. !released) but continue if the
944        // cursor is only released above a virtual node by accident (i.e. released). See #7018
945        if (ds == null || (shift && ctrl) || (ctrl && !released) || (virtualManager.hasVirtualWaysToBeConstructed() && !released))
946            return;
947
948        if (!released) {
949            // Don't replace the selection if the user clicked on a
950            // selected object (it breaks moving of selected groups).
951            // Do it later, on mouse release.
952            shift |= ds.getSelected().containsAll(prims);
953        }
954
955        if (ctrl) {
956            // Ctrl on an item toggles its selection status,
957            // but Ctrl on an *area* just clears those items
958            // out of the selection.
959            if (area) {
960                ds.clearSelection(prims);
961            } else {
962                ds.toggleSelected(prims);
963            }
964        } else if (shift) {
965            // add prims to an existing selection
966            ds.addSelected(prims);
967        } else {
968            // clear selection, then select the prims clicked
969            ds.setSelected(prims);
970        }
971    }
972
973    /**
974     * Returns the current select mode.
975     * @return the select mode
976     * @since 7543
977     */
978    public final Mode getMode() {
979        return mode;
980    }
981
982    @Override
983    public String getModeHelpText() {
984        if (mouseDownButton == MouseEvent.BUTTON1 && mouseReleaseTime < mouseDownTime) {
985            if (mode == Mode.SELECT)
986                return tr("Release the mouse button to select the objects in the rectangle.");
987            else if (mode == Mode.MOVE && (System.currentTimeMillis() - mouseDownTime >= initialMoveDelay)) {
988                final DataSet ds = getLayerManager().getEditDataSet();
989                final boolean canMerge = ds != null && !ds.getSelectedNodes().isEmpty();
990                final String mergeHelp = canMerge ? (' ' + tr("Ctrl to merge with nearest node.")) : "";
991                return tr("Release the mouse button to stop moving.") + mergeHelp;
992            } else if (mode == Mode.ROTATE)
993                return tr("Release the mouse button to stop rotating.");
994            else if (mode == Mode.SCALE)
995                return tr("Release the mouse button to stop scaling.");
996        }
997        return tr("Move objects by dragging; Shift to add to selection (Ctrl to toggle); Shift-Ctrl to rotate selected; " +
998                  "Alt-Ctrl to scale selected; or change selection");
999    }
1000
1001    @Override
1002    public boolean layerIsSupported(Layer l) {
1003        return l instanceof OsmDataLayer;
1004    }
1005
1006    /**
1007     * Enable or diable the lasso mode
1008     * @param lassoMode true to enable the lasso mode, false otherwise
1009     */
1010    public void setLassoMode(boolean lassoMode) {
1011        this.selectionManager.setLassoMode(lassoMode);
1012        this.lassoMode = lassoMode;
1013    }
1014
1015    private final transient CycleManager cycleManager = new CycleManager();
1016    private final transient VirtualManager virtualManager = new VirtualManager();
1017
1018    private class CycleManager {
1019
1020        private Collection<OsmPrimitive> cycleList = Collections.emptyList();
1021        private boolean cyclePrims;
1022        private OsmPrimitive cycleStart;
1023        private boolean waitForMouseUpParameter;
1024        private boolean multipleMatchesParameter;
1025        /**
1026         * read preferences
1027         */
1028        private void init() {
1029            waitForMouseUpParameter = Main.pref.getBoolean("mappaint.select.waits-for-mouse-up", false);
1030            multipleMatchesParameter = Main.pref.getBoolean("selectaction.cycles.multiple.matches", false);
1031        }
1032
1033        /**
1034         * Determine primitive to be selected and build cycleList
1035         * @param nearest primitive found by simple method
1036         * @param p point where user clicked
1037         * @return OsmPrimitive to be selected
1038         */
1039        private OsmPrimitive cycleSetup(OsmPrimitive nearest, Point p) {
1040            OsmPrimitive osm = null;
1041
1042            if (nearest != null) {
1043                osm = nearest;
1044
1045                if (!(alt || multipleMatchesParameter)) {
1046                    // no real cycling, just one element in cycle list
1047                    cycleList = asColl(osm);
1048
1049                    if (waitForMouseUpParameter) {
1050                        // prefer a selected nearest node or way, if possible
1051                        osm = mv.getNearestNodeOrWay(p, mv.isSelectablePredicate, true);
1052                    }
1053                } else {
1054                    // Alt + left mouse button pressed: we need to build cycle list
1055                    cycleList = mv.getAllNearest(p, mv.isSelectablePredicate);
1056
1057                    if (cycleList.size() > 1) {
1058                        cyclePrims = false;
1059
1060                        // find first already selected element in cycle list
1061                        OsmPrimitive old = osm;
1062                        for (OsmPrimitive o : cycleList) {
1063                            if (o.isSelected()) {
1064                                cyclePrims = true;
1065                                osm = o;
1066                                break;
1067                            }
1068                        }
1069
1070                        // special case:  for cycle groups of 2, we can toggle to the
1071                        // true nearest primitive on mousePressed right away
1072                        if (cycleList.size() == 2 && !waitForMouseUpParameter) {
1073                            if (!(osm.equals(old) || osm.isNew() || ctrl)) {
1074                                cyclePrims = false;
1075                                osm = old;
1076                            } // else defer toggling to mouseRelease time in those cases:
1077                            /*
1078                             * osm == old -- the true nearest node is the
1079                             * selected one osm is a new node -- do not break
1080                             * unglue ways in ALT mode ctrl is pressed -- ctrl
1081                             * generally works on mouseReleased
1082                             */
1083                        }
1084                    }
1085                }
1086            }
1087            return osm;
1088        }
1089
1090        /**
1091         * Modifies current selection state and returns the next element in a
1092         * selection cycle given by
1093         * <code>cycleList</code> field
1094         * @return the next element of cycle list
1095         */
1096        private Collection<OsmPrimitive> cyclePrims() {
1097            if (cycleList.size() <= 1) {
1098                // no real cycling, just return one-element collection with nearest primitive in it
1099                return cycleList;
1100            }
1101            // updateKeyModifiers() already called before!
1102
1103            DataSet ds = getLayerManager().getEditDataSet();
1104            OsmPrimitive first = cycleList.iterator().next(), foundInDS = null;
1105            OsmPrimitive nxt = first;
1106
1107            if (cyclePrims && shift) {
1108                for (Iterator<OsmPrimitive> i = cycleList.iterator(); i.hasNext();) {
1109                    nxt = i.next();
1110                    if (!nxt.isSelected()) {
1111                        break; // take first primitive in cycleList not in sel
1112                    }
1113                }
1114                // if primitives 1,2,3 are under cursor, [Alt-press] [Shift-release] gives 1 -> 12 -> 123
1115            } else {
1116                for (Iterator<OsmPrimitive> i = cycleList.iterator(); i.hasNext();) {
1117                    nxt = i.next();
1118                    if (nxt.isSelected()) {
1119                        foundInDS = nxt;
1120                        // first selected primitive in cycleList is found
1121                        if (cyclePrims || ctrl) {
1122                            ds.clearSelection(foundInDS); // deselect it
1123                            nxt = i.hasNext() ? i.next() : first;
1124                            // return next one in cycle list (last->first)
1125                        }
1126                        break; // take next primitive in cycleList
1127                    }
1128                }
1129            }
1130
1131            // if "no-alt-cycling" is enabled, Ctrl-Click arrives here.
1132            if (ctrl) {
1133                // a member of cycleList was found in the current dataset selection
1134                if (foundInDS != null) {
1135                    // mouse was moved to a different selection group w/ a previous sel
1136                    if (!cycleList.contains(cycleStart)) {
1137                        ds.clearSelection(cycleList);
1138                        cycleStart = foundInDS;
1139                    } else if (cycleStart.equals(nxt)) {
1140                        // loop detected, insert deselect step
1141                        ds.addSelected(nxt);
1142                    }
1143                } else {
1144                    // setup for iterating a sel group again or a new, different one..
1145                    nxt = cycleList.contains(cycleStart) ? cycleStart : first;
1146                    cycleStart = nxt;
1147                }
1148            } else {
1149                cycleStart = null;
1150            }
1151            // return one-element collection with one element to be selected (or added  to selection)
1152            return asColl(nxt);
1153        }
1154    }
1155
1156    private class VirtualManager {
1157
1158        private Node virtualNode;
1159        private Collection<WaySegment> virtualWays = new LinkedList<>();
1160        private int nodeVirtualSize;
1161        private int virtualSnapDistSq2;
1162        private int virtualSpace;
1163
1164        private void init() {
1165            nodeVirtualSize = Main.pref.getInteger("mappaint.node.virtual-size", 8);
1166            int virtualSnapDistSq = Main.pref.getInteger("mappaint.node.virtual-snap-distance", 8);
1167            virtualSnapDistSq2 = virtualSnapDistSq*virtualSnapDistSq;
1168            virtualSpace = Main.pref.getInteger("mappaint.node.virtual-space", 70);
1169        }
1170
1171        /**
1172         * Calculate a virtual node if there is enough visual space to draw a
1173         * crosshair node and the middle of a way segment is clicked. If the
1174         * user drags the crosshair node, it will be added to all ways in
1175         * <code>virtualWays</code>.
1176         *
1177         * @param p the point clicked
1178         * @return whether
1179         * <code>virtualNode</code> and
1180         * <code>virtualWays</code> were setup.
1181         */
1182        private boolean activateVirtualNodeNearPoint(Point p) {
1183            if (nodeVirtualSize > 0) {
1184
1185                Collection<WaySegment> selVirtualWays = new LinkedList<>();
1186                Pair<Node, Node> vnp = null, wnp = new Pair<>(null, null);
1187
1188                for (WaySegment ws : mv.getNearestWaySegments(p, mv.isSelectablePredicate)) {
1189                    Way w = ws.way;
1190
1191                    wnp.a = w.getNode(ws.lowerIndex);
1192                    wnp.b = w.getNode(ws.lowerIndex + 1);
1193                    MapViewPoint p1 = mv.getState().getPointFor(wnp.a);
1194                    MapViewPoint p2 = mv.getState().getPointFor(wnp.b);
1195                    if (WireframeMapRenderer.isLargeSegment(p1, p2, virtualSpace)) {
1196                        Point2D pc = new Point2D.Double((p1.getInViewX() + p2.getInViewX()) / 2, (p1.getInViewY() + p2.getInViewY()) / 2);
1197                        if (p.distanceSq(pc) < virtualSnapDistSq2) {
1198                            // Check that only segments on top of each other get added to the
1199                            // virtual ways list. Otherwise ways that coincidentally have their
1200                            // virtual node at the same spot will be joined which is likely unwanted
1201                            Pair.sort(wnp);
1202                            if (vnp == null) {
1203                                vnp = new Pair<>(wnp.a, wnp.b);
1204                                virtualNode = new Node(mv.getLatLon(pc.getX(), pc.getY()));
1205                            }
1206                            if (vnp.equals(wnp)) {
1207                                // if mutiple line segments have the same points,
1208                                // add all segments to be splitted to virtualWays list
1209                                // if some lines are selected, only their segments will go to virtualWays
1210                                (w.isSelected() ? selVirtualWays : virtualWays).add(ws);
1211                            }
1212                        }
1213                    }
1214                }
1215
1216                if (!selVirtualWays.isEmpty()) {
1217                    virtualWays = selVirtualWays;
1218                }
1219            }
1220
1221            return !virtualWays.isEmpty();
1222        }
1223
1224        private void createMiddleNodeFromVirtual(EastNorth currentEN) {
1225            Collection<Command> virtualCmds = new LinkedList<>();
1226            virtualCmds.add(new AddCommand(virtualNode));
1227            for (WaySegment virtualWay : virtualWays) {
1228                Way w = virtualWay.way;
1229                Way wnew = new Way(w);
1230                wnew.addNode(virtualWay.lowerIndex + 1, virtualNode);
1231                virtualCmds.add(new ChangeCommand(w, wnew));
1232            }
1233            virtualCmds.add(new MoveCommand(virtualNode, startEN, currentEN));
1234            String text = trn("Add and move a virtual new node to way",
1235                    "Add and move a virtual new node to {0} ways", virtualWays.size(),
1236                    virtualWays.size());
1237            Main.main.undoRedo.add(new SequenceCommand(text, virtualCmds));
1238            getLayerManager().getEditDataSet().setSelected(Collections.singleton((OsmPrimitive) virtualNode));
1239            clear();
1240        }
1241
1242        private void clear() {
1243            virtualWays.clear();
1244            virtualNode = null;
1245        }
1246
1247        private boolean hasVirtualNode() {
1248            return virtualNode != null;
1249        }
1250
1251        private boolean hasVirtualWaysToBeConstructed() {
1252            return !virtualWays.isEmpty();
1253        }
1254    }
1255
1256    /**
1257     * Returns {@code o} as collection of {@code o}'s type.
1258     * @param <T> object type
1259     * @param o any object
1260     * @return {@code o} as collection of {@code o}'s type.
1261     */
1262    protected static <T> Collection<T> asColl(T o) {
1263        if (o == null)
1264            return Collections.emptySet();
1265        return Collections.singleton(o);
1266    }
1267}