1/*
2 * Written by Doug Lea with assistance from members of JCP JSR-166
3 * Expert Group and released to the public domain, as explained at
4 * http://creativecommons.org/publicdomain/zero/1.0/
5 */
6
7package jsr166;
8
9import java.util.Arrays;
10import java.util.BitSet;
11import java.util.Collection;
12import java.util.Iterator;
13import java.util.Map;
14import java.util.NavigableMap;
15import java.util.NavigableSet;
16import java.util.NoSuchElementException;
17import java.util.Random;
18import java.util.Set;
19import java.util.TreeMap;
20
21import junit.framework.Test;
22import junit.framework.TestSuite;
23
24public class TreeMapTest extends JSR166TestCase {
25    // android-note: Removed because the CTS runner does a bad job of
26    // retrying tests that have suite() declarations.
27    //
28    // public static void main(String[] args) {
29    //     main(suite(), args);
30    // }
31    // public static Test suite() {
32    //     return new TestSuite(...);
33    // }
34
35    /**
36     * Returns a new map from Integers 1-5 to Strings "A"-"E".
37     */
38    private static TreeMap map5() {
39        TreeMap map = new TreeMap();
40        assertTrue(map.isEmpty());
41        map.put(one, "A");
42        map.put(five, "E");
43        map.put(three, "C");
44        map.put(two, "B");
45        map.put(four, "D");
46        assertFalse(map.isEmpty());
47        assertEquals(5, map.size());
48        return map;
49    }
50
51    /**
52     * clear removes all pairs
53     */
54    public void testClear() {
55        TreeMap map = map5();
56        map.clear();
57        assertEquals(0, map.size());
58    }
59
60    /**
61     * copy constructor creates map equal to source map
62     */
63    public void testConstructFromSorted() {
64        TreeMap map = map5();
65        TreeMap map2 = new TreeMap(map);
66        assertEquals(map, map2);
67    }
68
69    /**
70     * Maps with same contents are equal
71     */
72    public void testEquals() {
73        TreeMap map1 = map5();
74        TreeMap map2 = map5();
75        assertEquals(map1, map2);
76        assertEquals(map2, map1);
77        map1.clear();
78        assertFalse(map1.equals(map2));
79        assertFalse(map2.equals(map1));
80    }
81
82    /**
83     * containsKey returns true for contained key
84     */
85    public void testContainsKey() {
86        TreeMap map = map5();
87        assertTrue(map.containsKey(one));
88        assertFalse(map.containsKey(zero));
89    }
90
91    /**
92     * containsValue returns true for held values
93     */
94    public void testContainsValue() {
95        TreeMap map = map5();
96        assertTrue(map.containsValue("A"));
97        assertFalse(map.containsValue("Z"));
98    }
99
100    /**
101     * get returns the correct element at the given key,
102     * or null if not present
103     */
104    public void testGet() {
105        TreeMap map = map5();
106        assertEquals("A", (String)map.get(one));
107        TreeMap empty = new TreeMap();
108        assertNull(empty.get(one));
109    }
110
111    /**
112     * isEmpty is true of empty map and false for non-empty
113     */
114    public void testIsEmpty() {
115        TreeMap empty = new TreeMap();
116        TreeMap map = map5();
117        assertTrue(empty.isEmpty());
118        assertFalse(map.isEmpty());
119    }
120
121    /**
122     * firstKey returns first key
123     */
124    public void testFirstKey() {
125        TreeMap map = map5();
126        assertEquals(one, map.firstKey());
127    }
128
129    /**
130     * lastKey returns last key
131     */
132    public void testLastKey() {
133        TreeMap map = map5();
134        assertEquals(five, map.lastKey());
135    }
136
137    /**
138     * keySet.toArray returns contains all keys
139     */
140    public void testKeySetToArray() {
141        TreeMap map = map5();
142        Set s = map.keySet();
143        Object[] ar = s.toArray();
144        assertTrue(s.containsAll(Arrays.asList(ar)));
145        assertEquals(5, ar.length);
146        ar[0] = m10;
147        assertFalse(s.containsAll(Arrays.asList(ar)));
148    }
149
150    /**
151     * descendingkeySet.toArray returns contains all keys
152     */
153    public void testDescendingKeySetToArray() {
154        TreeMap map = map5();
155        Set s = map.descendingKeySet();
156        Object[] ar = s.toArray();
157        assertEquals(5, ar.length);
158        assertTrue(s.containsAll(Arrays.asList(ar)));
159        ar[0] = m10;
160        assertFalse(s.containsAll(Arrays.asList(ar)));
161    }
162
163    /**
164     * keySet returns a Set containing all the keys
165     */
166    public void testKeySet() {
167        TreeMap map = map5();
168        Set s = map.keySet();
169        assertEquals(5, s.size());
170        assertTrue(s.contains(one));
171        assertTrue(s.contains(two));
172        assertTrue(s.contains(three));
173        assertTrue(s.contains(four));
174        assertTrue(s.contains(five));
175    }
176
177    /**
178     * keySet is ordered
179     */
180    public void testKeySetOrder() {
181        TreeMap map = map5();
182        Set s = map.keySet();
183        Iterator i = s.iterator();
184        Integer last = (Integer)i.next();
185        assertEquals(last, one);
186        int count = 1;
187        while (i.hasNext()) {
188            Integer k = (Integer)i.next();
189            assertTrue(last.compareTo(k) < 0);
190            last = k;
191            ++count;
192        }
193        assertEquals(5, count);
194    }
195
196    /**
197     * descending iterator of key set is inverse ordered
198     */
199    public void testKeySetDescendingIteratorOrder() {
200        TreeMap map = map5();
201        NavigableSet s = map.navigableKeySet();
202        Iterator i = s.descendingIterator();
203        Integer last = (Integer)i.next();
204        assertEquals(last, five);
205        int count = 1;
206        while (i.hasNext()) {
207            Integer k = (Integer)i.next();
208            assertTrue(last.compareTo(k) > 0);
209            last = k;
210            ++count;
211        }
212        assertEquals(5, count);
213    }
214
215    /**
216     * descendingKeySet is ordered
217     */
218    public void testDescendingKeySetOrder() {
219        TreeMap map = map5();
220        Set s = map.descendingKeySet();
221        Iterator i = s.iterator();
222        Integer last = (Integer)i.next();
223        assertEquals(last, five);
224        int count = 1;
225        while (i.hasNext()) {
226            Integer k = (Integer)i.next();
227            assertTrue(last.compareTo(k) > 0);
228            last = k;
229            ++count;
230        }
231        assertEquals(5, count);
232    }
233
234    /**
235     * descending iterator of descendingKeySet is ordered
236     */
237    public void testDescendingKeySetDescendingIteratorOrder() {
238        TreeMap map = map5();
239        NavigableSet s = map.descendingKeySet();
240        Iterator i = s.descendingIterator();
241        Integer last = (Integer)i.next();
242        assertEquals(last, one);
243        int count = 1;
244        while (i.hasNext()) {
245            Integer k = (Integer)i.next();
246            assertTrue(last.compareTo(k) < 0);
247            last = k;
248            ++count;
249        }
250        assertEquals(5, count);
251    }
252
253    /**
254     * values collection contains all values
255     */
256    public void testValues() {
257        TreeMap map = map5();
258        Collection s = map.values();
259        assertEquals(5, s.size());
260        assertTrue(s.contains("A"));
261        assertTrue(s.contains("B"));
262        assertTrue(s.contains("C"));
263        assertTrue(s.contains("D"));
264        assertTrue(s.contains("E"));
265    }
266
267    /**
268     * entrySet contains all pairs
269     */
270    public void testEntrySet() {
271        TreeMap map = map5();
272        Set s = map.entrySet();
273        assertEquals(5, s.size());
274        Iterator it = s.iterator();
275        while (it.hasNext()) {
276            Map.Entry e = (Map.Entry) it.next();
277            assertTrue(
278                       (e.getKey().equals(one) && e.getValue().equals("A")) ||
279                       (e.getKey().equals(two) && e.getValue().equals("B")) ||
280                       (e.getKey().equals(three) && e.getValue().equals("C")) ||
281                       (e.getKey().equals(four) && e.getValue().equals("D")) ||
282                       (e.getKey().equals(five) && e.getValue().equals("E")));
283        }
284    }
285
286    /**
287     * descendingEntrySet contains all pairs
288     */
289    public void testDescendingEntrySet() {
290        TreeMap map = map5();
291        Set s = map.descendingMap().entrySet();
292        assertEquals(5, s.size());
293        Iterator it = s.iterator();
294        while (it.hasNext()) {
295            Map.Entry e = (Map.Entry) it.next();
296            assertTrue(
297                       (e.getKey().equals(one) && e.getValue().equals("A")) ||
298                       (e.getKey().equals(two) && e.getValue().equals("B")) ||
299                       (e.getKey().equals(three) && e.getValue().equals("C")) ||
300                       (e.getKey().equals(four) && e.getValue().equals("D")) ||
301                       (e.getKey().equals(five) && e.getValue().equals("E")));
302        }
303    }
304
305    /**
306     * entrySet.toArray contains all entries
307     */
308    public void testEntrySetToArray() {
309        TreeMap map = map5();
310        Set s = map.entrySet();
311        Object[] ar = s.toArray();
312        assertEquals(5, ar.length);
313        for (int i = 0; i < 5; ++i) {
314            assertTrue(map.containsKey(((Map.Entry)(ar[i])).getKey()));
315            assertTrue(map.containsValue(((Map.Entry)(ar[i])).getValue()));
316        }
317    }
318
319    /**
320     * descendingEntrySet.toArray contains all entries
321     */
322    public void testDescendingEntrySetToArray() {
323        TreeMap map = map5();
324        Set s = map.descendingMap().entrySet();
325        Object[] ar = s.toArray();
326        assertEquals(5, ar.length);
327        for (int i = 0; i < 5; ++i) {
328            assertTrue(map.containsKey(((Map.Entry)(ar[i])).getKey()));
329            assertTrue(map.containsValue(((Map.Entry)(ar[i])).getValue()));
330        }
331    }
332
333    /**
334     * putAll adds all key-value pairs from the given map
335     */
336    public void testPutAll() {
337        TreeMap empty = new TreeMap();
338        TreeMap map = map5();
339        empty.putAll(map);
340        assertEquals(5, empty.size());
341        assertTrue(empty.containsKey(one));
342        assertTrue(empty.containsKey(two));
343        assertTrue(empty.containsKey(three));
344        assertTrue(empty.containsKey(four));
345        assertTrue(empty.containsKey(five));
346    }
347
348    /**
349     * remove removes the correct key-value pair from the map
350     */
351    public void testRemove() {
352        TreeMap map = map5();
353        map.remove(five);
354        assertEquals(4, map.size());
355        assertFalse(map.containsKey(five));
356    }
357
358    /**
359     * lowerEntry returns preceding entry.
360     */
361    public void testLowerEntry() {
362        TreeMap map = map5();
363        Map.Entry e1 = map.lowerEntry(three);
364        assertEquals(two, e1.getKey());
365
366        Map.Entry e2 = map.lowerEntry(six);
367        assertEquals(five, e2.getKey());
368
369        Map.Entry e3 = map.lowerEntry(one);
370        assertNull(e3);
371
372        Map.Entry e4 = map.lowerEntry(zero);
373        assertNull(e4);
374    }
375
376    /**
377     * higherEntry returns next entry.
378     */
379    public void testHigherEntry() {
380        TreeMap map = map5();
381        Map.Entry e1 = map.higherEntry(three);
382        assertEquals(four, e1.getKey());
383
384        Map.Entry e2 = map.higherEntry(zero);
385        assertEquals(one, e2.getKey());
386
387        Map.Entry e3 = map.higherEntry(five);
388        assertNull(e3);
389
390        Map.Entry e4 = map.higherEntry(six);
391        assertNull(e4);
392    }
393
394    /**
395     * floorEntry returns preceding entry.
396     */
397    public void testFloorEntry() {
398        TreeMap map = map5();
399        Map.Entry e1 = map.floorEntry(three);
400        assertEquals(three, e1.getKey());
401
402        Map.Entry e2 = map.floorEntry(six);
403        assertEquals(five, e2.getKey());
404
405        Map.Entry e3 = map.floorEntry(one);
406        assertEquals(one, e3.getKey());
407
408        Map.Entry e4 = map.floorEntry(zero);
409        assertNull(e4);
410    }
411
412    /**
413     * ceilingEntry returns next entry.
414     */
415    public void testCeilingEntry() {
416        TreeMap map = map5();
417        Map.Entry e1 = map.ceilingEntry(three);
418        assertEquals(three, e1.getKey());
419
420        Map.Entry e2 = map.ceilingEntry(zero);
421        assertEquals(one, e2.getKey());
422
423        Map.Entry e3 = map.ceilingEntry(five);
424        assertEquals(five, e3.getKey());
425
426        Map.Entry e4 = map.ceilingEntry(six);
427        assertNull(e4);
428    }
429
430    /**
431     * lowerKey returns preceding element
432     */
433    public void testLowerKey() {
434        TreeMap q = map5();
435        Object e1 = q.lowerKey(three);
436        assertEquals(two, e1);
437
438        Object e2 = q.lowerKey(six);
439        assertEquals(five, e2);
440
441        Object e3 = q.lowerKey(one);
442        assertNull(e3);
443
444        Object e4 = q.lowerKey(zero);
445        assertNull(e4);
446    }
447
448    /**
449     * higherKey returns next element
450     */
451    public void testHigherKey() {
452        TreeMap q = map5();
453        Object e1 = q.higherKey(three);
454        assertEquals(four, e1);
455
456        Object e2 = q.higherKey(zero);
457        assertEquals(one, e2);
458
459        Object e3 = q.higherKey(five);
460        assertNull(e3);
461
462        Object e4 = q.higherKey(six);
463        assertNull(e4);
464    }
465
466    /**
467     * floorKey returns preceding element
468     */
469    public void testFloorKey() {
470        TreeMap q = map5();
471        Object e1 = q.floorKey(three);
472        assertEquals(three, e1);
473
474        Object e2 = q.floorKey(six);
475        assertEquals(five, e2);
476
477        Object e3 = q.floorKey(one);
478        assertEquals(one, e3);
479
480        Object e4 = q.floorKey(zero);
481        assertNull(e4);
482    }
483
484    /**
485     * ceilingKey returns next element
486     */
487    public void testCeilingKey() {
488        TreeMap q = map5();
489        Object e1 = q.ceilingKey(three);
490        assertEquals(three, e1);
491
492        Object e2 = q.ceilingKey(zero);
493        assertEquals(one, e2);
494
495        Object e3 = q.ceilingKey(five);
496        assertEquals(five, e3);
497
498        Object e4 = q.ceilingKey(six);
499        assertNull(e4);
500    }
501
502    /**
503     * pollFirstEntry returns entries in order
504     */
505    public void testPollFirstEntry() {
506        TreeMap map = map5();
507        Map.Entry e = map.pollFirstEntry();
508        assertEquals(one, e.getKey());
509        assertEquals("A", e.getValue());
510        e = map.pollFirstEntry();
511        assertEquals(two, e.getKey());
512        map.put(one, "A");
513        e = map.pollFirstEntry();
514        assertEquals(one, e.getKey());
515        assertEquals("A", e.getValue());
516        e = map.pollFirstEntry();
517        assertEquals(three, e.getKey());
518        map.remove(four);
519        e = map.pollFirstEntry();
520        assertEquals(five, e.getKey());
521        try {
522            e.setValue("A");
523            shouldThrow();
524        } catch (UnsupportedOperationException success) {}
525        e = map.pollFirstEntry();
526        assertNull(e);
527    }
528
529    /**
530     * pollLastEntry returns entries in order
531     */
532    public void testPollLastEntry() {
533        TreeMap map = map5();
534        Map.Entry e = map.pollLastEntry();
535        assertEquals(five, e.getKey());
536        assertEquals("E", e.getValue());
537        e = map.pollLastEntry();
538        assertEquals(four, e.getKey());
539        map.put(five, "E");
540        e = map.pollLastEntry();
541        assertEquals(five, e.getKey());
542        assertEquals("E", e.getValue());
543        e = map.pollLastEntry();
544        assertEquals(three, e.getKey());
545        map.remove(two);
546        e = map.pollLastEntry();
547        assertEquals(one, e.getKey());
548        try {
549            e.setValue("E");
550            shouldThrow();
551        } catch (UnsupportedOperationException success) {}
552        e = map.pollLastEntry();
553        assertNull(e);
554    }
555
556    /**
557     * size returns the correct values
558     */
559    public void testSize() {
560        TreeMap map = map5();
561        TreeMap empty = new TreeMap();
562        assertEquals(0, empty.size());
563        assertEquals(5, map.size());
564    }
565
566    /**
567     * toString contains toString of elements
568     */
569    public void testToString() {
570        TreeMap map = map5();
571        String s = map.toString();
572        for (int i = 1; i <= 5; ++i) {
573            assertTrue(s.contains(String.valueOf(i)));
574        }
575    }
576
577    // Exception tests
578
579    /**
580     * get(null) of nonempty map throws NPE
581     */
582    public void testGet_NullPointerException() {
583        TreeMap c = map5();
584        try {
585            c.get(null);
586            shouldThrow();
587        } catch (NullPointerException success) {}
588    }
589
590    /**
591     * containsKey(null) of nonempty map throws NPE
592     */
593    public void testContainsKey_NullPointerException() {
594        TreeMap c = map5();
595        try {
596            c.containsKey(null);
597            shouldThrow();
598        } catch (NullPointerException success) {}
599    }
600
601    /**
602     * remove(null) throws NPE for nonempty map
603     */
604    public void testRemove1_NullPointerException() {
605        TreeMap c = new TreeMap();
606        c.put("sadsdf", "asdads");
607        try {
608            c.remove(null);
609            shouldThrow();
610        } catch (NullPointerException success) {}
611    }
612
613    /**
614     * A deserialized map equals original
615     */
616    public void testSerialization() throws Exception {
617        NavigableMap x = map5();
618        NavigableMap y = serialClone(x);
619
620        assertNotSame(x, y);
621        assertEquals(x.size(), y.size());
622        assertEquals(x.toString(), y.toString());
623        assertEquals(x, y);
624        assertEquals(y, x);
625    }
626
627    /**
628     * subMap returns map with keys in requested range
629     */
630    public void testSubMapContents() {
631        TreeMap map = map5();
632        NavigableMap sm = map.subMap(two, true, four, false);
633        assertEquals(two, sm.firstKey());
634        assertEquals(three, sm.lastKey());
635        assertEquals(2, sm.size());
636        assertFalse(sm.containsKey(one));
637        assertTrue(sm.containsKey(two));
638        assertTrue(sm.containsKey(three));
639        assertFalse(sm.containsKey(four));
640        assertFalse(sm.containsKey(five));
641        Iterator i = sm.keySet().iterator();
642        Object k;
643        k = (Integer)(i.next());
644        assertEquals(two, k);
645        k = (Integer)(i.next());
646        assertEquals(three, k);
647        assertFalse(i.hasNext());
648        Iterator r = sm.descendingKeySet().iterator();
649        k = (Integer)(r.next());
650        assertEquals(three, k);
651        k = (Integer)(r.next());
652        assertEquals(two, k);
653        assertFalse(r.hasNext());
654
655        Iterator j = sm.keySet().iterator();
656        j.next();
657        j.remove();
658        assertFalse(map.containsKey(two));
659        assertEquals(4, map.size());
660        assertEquals(1, sm.size());
661        assertEquals(three, sm.firstKey());
662        assertEquals(three, sm.lastKey());
663        assertEquals("C", sm.remove(three));
664        assertTrue(sm.isEmpty());
665        assertEquals(3, map.size());
666    }
667
668    public void testSubMapContents2() {
669        TreeMap map = map5();
670        NavigableMap sm = map.subMap(two, true, three, false);
671        assertEquals(1, sm.size());
672        assertEquals(two, sm.firstKey());
673        assertEquals(two, sm.lastKey());
674        assertFalse(sm.containsKey(one));
675        assertTrue(sm.containsKey(two));
676        assertFalse(sm.containsKey(three));
677        assertFalse(sm.containsKey(four));
678        assertFalse(sm.containsKey(five));
679        Iterator i = sm.keySet().iterator();
680        Object k;
681        k = (Integer)(i.next());
682        assertEquals(two, k);
683        assertFalse(i.hasNext());
684        Iterator r = sm.descendingKeySet().iterator();
685        k = (Integer)(r.next());
686        assertEquals(two, k);
687        assertFalse(r.hasNext());
688
689        Iterator j = sm.keySet().iterator();
690        j.next();
691        j.remove();
692        assertFalse(map.containsKey(two));
693        assertEquals(4, map.size());
694        assertEquals(0, sm.size());
695        assertTrue(sm.isEmpty());
696        assertSame(sm.remove(three), null);
697        assertEquals(4, map.size());
698    }
699
700    /**
701     * headMap returns map with keys in requested range
702     */
703    public void testHeadMapContents() {
704        TreeMap map = map5();
705        NavigableMap sm = map.headMap(four, false);
706        assertTrue(sm.containsKey(one));
707        assertTrue(sm.containsKey(two));
708        assertTrue(sm.containsKey(three));
709        assertFalse(sm.containsKey(four));
710        assertFalse(sm.containsKey(five));
711        Iterator i = sm.keySet().iterator();
712        Object k;
713        k = (Integer)(i.next());
714        assertEquals(one, k);
715        k = (Integer)(i.next());
716        assertEquals(two, k);
717        k = (Integer)(i.next());
718        assertEquals(three, k);
719        assertFalse(i.hasNext());
720        sm.clear();
721        assertTrue(sm.isEmpty());
722        assertEquals(2, map.size());
723        assertEquals(four, map.firstKey());
724    }
725
726    /**
727     * headMap returns map with keys in requested range
728     */
729    public void testTailMapContents() {
730        TreeMap map = map5();
731        NavigableMap sm = map.tailMap(two, true);
732        assertFalse(sm.containsKey(one));
733        assertTrue(sm.containsKey(two));
734        assertTrue(sm.containsKey(three));
735        assertTrue(sm.containsKey(four));
736        assertTrue(sm.containsKey(five));
737        Iterator i = sm.keySet().iterator();
738        Object k;
739        k = (Integer)(i.next());
740        assertEquals(two, k);
741        k = (Integer)(i.next());
742        assertEquals(three, k);
743        k = (Integer)(i.next());
744        assertEquals(four, k);
745        k = (Integer)(i.next());
746        assertEquals(five, k);
747        assertFalse(i.hasNext());
748        Iterator r = sm.descendingKeySet().iterator();
749        k = (Integer)(r.next());
750        assertEquals(five, k);
751        k = (Integer)(r.next());
752        assertEquals(four, k);
753        k = (Integer)(r.next());
754        assertEquals(three, k);
755        k = (Integer)(r.next());
756        assertEquals(two, k);
757        assertFalse(r.hasNext());
758
759        Iterator ei = sm.entrySet().iterator();
760        Map.Entry e;
761        e = (Map.Entry)(ei.next());
762        assertEquals(two, e.getKey());
763        assertEquals("B", e.getValue());
764        e = (Map.Entry)(ei.next());
765        assertEquals(three, e.getKey());
766        assertEquals("C", e.getValue());
767        e = (Map.Entry)(ei.next());
768        assertEquals(four, e.getKey());
769        assertEquals("D", e.getValue());
770        e = (Map.Entry)(ei.next());
771        assertEquals(five, e.getKey());
772        assertEquals("E", e.getValue());
773        assertFalse(i.hasNext());
774
775        NavigableMap ssm = sm.tailMap(four, true);
776        assertEquals(four, ssm.firstKey());
777        assertEquals(five, ssm.lastKey());
778        assertEquals("D", ssm.remove(four));
779        assertEquals(1, ssm.size());
780        assertEquals(3, sm.size());
781        assertEquals(4, map.size());
782    }
783
784    Random rnd = new Random(666);
785    BitSet bs;
786
787    /**
788     * Submaps of submaps subdivide correctly
789     */
790    public void testRecursiveSubMaps() throws Exception {
791        int mapSize = expensiveTests ? 1000 : 100;
792        Class cl = TreeMap.class;
793        NavigableMap<Integer, Integer> map = newMap(cl);
794        bs = new BitSet(mapSize);
795
796        populate(map, mapSize);
797        check(map,                 0, mapSize - 1, true);
798        check(map.descendingMap(), 0, mapSize - 1, false);
799
800        mutateMap(map, 0, mapSize - 1);
801        check(map,                 0, mapSize - 1, true);
802        check(map.descendingMap(), 0, mapSize - 1, false);
803
804        bashSubMap(map.subMap(0, true, mapSize, false),
805                   0, mapSize - 1, true);
806    }
807
808    static NavigableMap<Integer, Integer> newMap(Class cl) throws Exception {
809        NavigableMap<Integer, Integer> result
810            = (NavigableMap<Integer, Integer>) cl.newInstance();
811        assertEquals(0, result.size());
812        assertFalse(result.keySet().iterator().hasNext());
813        return result;
814    }
815
816    void populate(NavigableMap<Integer, Integer> map, int limit) {
817        for (int i = 0, n = 2 * limit / 3; i < n; i++) {
818            int key = rnd.nextInt(limit);
819            put(map, key);
820        }
821    }
822
823    void mutateMap(NavigableMap<Integer, Integer> map, int min, int max) {
824        int size = map.size();
825        int rangeSize = max - min + 1;
826
827        // Remove a bunch of entries directly
828        for (int i = 0, n = rangeSize / 2; i < n; i++) {
829            remove(map, min - 5 + rnd.nextInt(rangeSize + 10));
830        }
831
832        // Remove a bunch of entries with iterator
833        for (Iterator<Integer> it = map.keySet().iterator(); it.hasNext(); ) {
834            if (rnd.nextBoolean()) {
835                bs.clear(it.next());
836                it.remove();
837            }
838        }
839
840        // Add entries till we're back to original size
841        while (map.size() < size) {
842            int key = min + rnd.nextInt(rangeSize);
843            assertTrue(key >= min && key <= max);
844            put(map, key);
845        }
846    }
847
848    void mutateSubMap(NavigableMap<Integer, Integer> map, int min, int max) {
849        int size = map.size();
850        int rangeSize = max - min + 1;
851
852        // Remove a bunch of entries directly
853        for (int i = 0, n = rangeSize / 2; i < n; i++) {
854            remove(map, min - 5 + rnd.nextInt(rangeSize + 10));
855        }
856
857        // Remove a bunch of entries with iterator
858        for (Iterator<Integer> it = map.keySet().iterator(); it.hasNext(); ) {
859            if (rnd.nextBoolean()) {
860                bs.clear(it.next());
861                it.remove();
862            }
863        }
864
865        // Add entries till we're back to original size
866        while (map.size() < size) {
867            int key = min - 5 + rnd.nextInt(rangeSize + 10);
868            if (key >= min && key <= max) {
869                put(map, key);
870            } else {
871                try {
872                    map.put(key, 2 * key);
873                    shouldThrow();
874                } catch (IllegalArgumentException success) {}
875            }
876        }
877    }
878
879    void put(NavigableMap<Integer, Integer> map, int key) {
880        if (map.put(key, 2 * key) == null)
881            bs.set(key);
882    }
883
884    void remove(NavigableMap<Integer, Integer> map, int key) {
885        if (map.remove(key) != null)
886            bs.clear(key);
887    }
888
889    void bashSubMap(NavigableMap<Integer, Integer> map,
890                    int min, int max, boolean ascending) {
891        check(map, min, max, ascending);
892        check(map.descendingMap(), min, max, !ascending);
893
894        mutateSubMap(map, min, max);
895        check(map, min, max, ascending);
896        check(map.descendingMap(), min, max, !ascending);
897
898        // Recurse
899        if (max - min < 2)
900            return;
901        int midPoint = (min + max) / 2;
902
903        // headMap - pick direction and endpoint inclusion randomly
904        boolean incl = rnd.nextBoolean();
905        NavigableMap<Integer,Integer> hm = map.headMap(midPoint, incl);
906        if (ascending) {
907            if (rnd.nextBoolean())
908                bashSubMap(hm, min, midPoint - (incl ? 0 : 1), true);
909            else
910                bashSubMap(hm.descendingMap(), min, midPoint - (incl ? 0 : 1),
911                           false);
912        } else {
913            if (rnd.nextBoolean())
914                bashSubMap(hm, midPoint + (incl ? 0 : 1), max, false);
915            else
916                bashSubMap(hm.descendingMap(), midPoint + (incl ? 0 : 1), max,
917                           true);
918        }
919
920        // tailMap - pick direction and endpoint inclusion randomly
921        incl = rnd.nextBoolean();
922        NavigableMap<Integer,Integer> tm = map.tailMap(midPoint,incl);
923        if (ascending) {
924            if (rnd.nextBoolean())
925                bashSubMap(tm, midPoint + (incl ? 0 : 1), max, true);
926            else
927                bashSubMap(tm.descendingMap(), midPoint + (incl ? 0 : 1), max,
928                           false);
929        } else {
930            if (rnd.nextBoolean()) {
931                bashSubMap(tm, min, midPoint - (incl ? 0 : 1), false);
932            } else {
933                bashSubMap(tm.descendingMap(), min, midPoint - (incl ? 0 : 1),
934                           true);
935            }
936        }
937
938        // subMap - pick direction and endpoint inclusion randomly
939        int rangeSize = max - min + 1;
940        int[] endpoints = new int[2];
941        endpoints[0] = min + rnd.nextInt(rangeSize);
942        endpoints[1] = min + rnd.nextInt(rangeSize);
943        Arrays.sort(endpoints);
944        boolean lowIncl = rnd.nextBoolean();
945        boolean highIncl = rnd.nextBoolean();
946        if (ascending) {
947            NavigableMap<Integer,Integer> sm = map.subMap(
948                endpoints[0], lowIncl, endpoints[1], highIncl);
949            if (rnd.nextBoolean())
950                bashSubMap(sm, endpoints[0] + (lowIncl ? 0 : 1),
951                           endpoints[1] - (highIncl ? 0 : 1), true);
952            else
953                bashSubMap(sm.descendingMap(), endpoints[0] + (lowIncl ? 0 : 1),
954                           endpoints[1] - (highIncl ? 0 : 1), false);
955        } else {
956            NavigableMap<Integer,Integer> sm = map.subMap(
957                endpoints[1], highIncl, endpoints[0], lowIncl);
958            if (rnd.nextBoolean())
959                bashSubMap(sm, endpoints[0] + (lowIncl ? 0 : 1),
960                           endpoints[1] - (highIncl ? 0 : 1), false);
961            else
962                bashSubMap(sm.descendingMap(), endpoints[0] + (lowIncl ? 0 : 1),
963                           endpoints[1] - (highIncl ? 0 : 1), true);
964        }
965    }
966
967    /**
968     * min and max are both inclusive.  If max < min, interval is empty.
969     */
970    void check(NavigableMap<Integer, Integer> map,
971                      final int min, final int max, final boolean ascending) {
972        class ReferenceSet {
973            int lower(int key) {
974                return ascending ? lowerAscending(key) : higherAscending(key);
975            }
976            int floor(int key) {
977                return ascending ? floorAscending(key) : ceilingAscending(key);
978            }
979            int ceiling(int key) {
980                return ascending ? ceilingAscending(key) : floorAscending(key);
981            }
982            int higher(int key) {
983                return ascending ? higherAscending(key) : lowerAscending(key);
984            }
985            int first() {
986                return ascending ? firstAscending() : lastAscending();
987            }
988            int last() {
989                return ascending ? lastAscending() : firstAscending();
990            }
991            int lowerAscending(int key) {
992                return floorAscending(key - 1);
993            }
994            int floorAscending(int key) {
995                if (key < min)
996                    return -1;
997                else if (key > max)
998                    key = max;
999
1000                // BitSet should support this! Test would run much faster
1001                while (key >= min) {
1002                    if (bs.get(key))
1003                        return key;
1004                    key--;
1005                }
1006                return -1;
1007            }
1008            int ceilingAscending(int key) {
1009                if (key < min)
1010                    key = min;
1011                else if (key > max)
1012                    return -1;
1013                int result = bs.nextSetBit(key);
1014                return result > max ? -1 : result;
1015            }
1016            int higherAscending(int key) {
1017                return ceilingAscending(key + 1);
1018            }
1019            private int firstAscending() {
1020                int result = ceilingAscending(min);
1021                return result > max ? -1 : result;
1022            }
1023            private int lastAscending() {
1024                int result = floorAscending(max);
1025                return result < min ? -1 : result;
1026            }
1027        }
1028        ReferenceSet rs = new ReferenceSet();
1029
1030        // Test contents using containsKey
1031        int size = 0;
1032        for (int i = min; i <= max; i++) {
1033            boolean bsContainsI = bs.get(i);
1034            assertEquals(bsContainsI, map.containsKey(i));
1035            if (bsContainsI)
1036                size++;
1037        }
1038        assertEquals(size, map.size());
1039
1040        // Test contents using contains keySet iterator
1041        int size2 = 0;
1042        int previousKey = -1;
1043        for (int key : map.keySet()) {
1044            assertTrue(bs.get(key));
1045            size2++;
1046            assertTrue(previousKey < 0 ||
1047                (ascending ? key - previousKey > 0 : key - previousKey < 0));
1048            previousKey = key;
1049        }
1050        assertEquals(size2, size);
1051
1052        // Test navigation ops
1053        for (int key = min - 1; key <= max + 1; key++) {
1054            assertEq(map.lowerKey(key), rs.lower(key));
1055            assertEq(map.floorKey(key), rs.floor(key));
1056            assertEq(map.higherKey(key), rs.higher(key));
1057            assertEq(map.ceilingKey(key), rs.ceiling(key));
1058        }
1059
1060        // Test extrema
1061        if (map.size() != 0) {
1062            assertEq(map.firstKey(), rs.first());
1063            assertEq(map.lastKey(), rs.last());
1064        } else {
1065            assertEq(rs.first(), -1);
1066            assertEq(rs.last(),  -1);
1067            try {
1068                map.firstKey();
1069                shouldThrow();
1070            } catch (NoSuchElementException success) {}
1071            try {
1072                map.lastKey();
1073                shouldThrow();
1074            } catch (NoSuchElementException success) {}
1075        }
1076    }
1077
1078    static void assertEq(Integer i, int j) {
1079        if (i == null)
1080            assertEquals(j, -1);
1081        else
1082            assertEquals((int) i, j);
1083    }
1084
1085    static boolean eq(Integer i, int j) {
1086        return i == null ? j == -1 : i == j;
1087    }
1088
1089}
1090