--- jsr166/src/test/tck/LinkedListTest.java 2010/11/03 07:54:52 1.21 +++ jsr166/src/test/tck/LinkedListTest.java 2021/01/26 13:33:06 1.50 @@ -1,35 +1,64 @@ /* * Written by Doug Lea with assistance from members of JCP JSR-166 * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/licenses/publicdomain + * http://creativecommons.org/publicdomain/zero/1.0/ * Other contributors include Andrew Wright, Jeffrey Hayes, * Pat Fisher, Mike Judd. */ -import junit.framework.*; -import java.util.*; -import java.util.concurrent.*; +import java.util.Arrays; +import java.util.Collection; +import java.util.Iterator; +import java.util.LinkedList; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.concurrent.ThreadLocalRandom; + +import junit.framework.Test; public class LinkedListTest extends JSR166TestCase { public static void main(String[] args) { - junit.textui.TestRunner.run(suite()); + main(suite(), args); } public static Test suite() { - return new TestSuite(LinkedListTest.class); + class Implementation implements CollectionImplementation { + public Class klazz() { return LinkedList.class; } + public List emptyCollection() { return new LinkedList(); } + public Object makeElement(int i) { return JSR166TestCase.itemFor(i); } + public boolean isConcurrent() { return false; } + public boolean permitsNulls() { return true; } + } + class SubListImplementation extends Implementation { + @SuppressWarnings("unchecked") + public List emptyCollection() { + List list = super.emptyCollection(); + ThreadLocalRandom rnd = ThreadLocalRandom.current(); + if (rnd.nextBoolean()) + list.add(makeElement(rnd.nextInt())); + int i = rnd.nextInt(list.size() + 1); + return list.subList(i, i); + } + } + return newTestSuite( + LinkedListTest.class, + CollectionTest.testSuite(new Implementation()), + CollectionTest.testSuite(new SubListImplementation())); } /** - * Create a queue of given size containing consecutive - * Integers 0 ... n. + * Returns a new queue of given size containing consecutive + * Items 0 ... n - 1. */ - private LinkedList populatedQueue(int n) { - LinkedList q = new LinkedList(); + private static LinkedList populatedQueue(int n) { + LinkedList q = new LinkedList<>(); assertTrue(q.isEmpty()); for (int i = 0; i < n; ++i) - assertTrue(q.offer(new Integer(i))); + mustOffer(q, i); assertFalse(q.isEmpty()); - assertEquals(n, q.size()); + mustEqual(n, q.size()); + mustEqual(0, q.peekFirst()); + mustEqual((n - 1), q.peekLast()); return q; } @@ -37,7 +66,7 @@ public class LinkedListTest extends JSR1 * new queue is empty */ public void testConstructor1() { - assertEquals(0, new LinkedList().size()); + mustEqual(0, new LinkedList().size()); } /** @@ -45,7 +74,7 @@ public class LinkedListTest extends JSR1 */ public void testConstructor3() { try { - LinkedList q = new LinkedList((Collection)null); + new LinkedList((Collection)null); shouldThrow(); } catch (NullPointerException success) {} } @@ -54,23 +83,21 @@ public class LinkedListTest extends JSR1 * Queue contains all elements of collection used to initialize */ public void testConstructor6() { - Integer[] ints = new Integer[SIZE]; - for (int i = 0; i < SIZE; ++i) - ints[i] = i; - LinkedList q = new LinkedList(Arrays.asList(ints)); + Item[] items = defaultItems; + LinkedList q = new LinkedList(Arrays.asList(items)); for (int i = 0; i < SIZE; ++i) - assertEquals(ints[i], q.poll()); + mustEqual(items[i], q.poll()); } /** * isEmpty is true before add, false after */ public void testEmpty() { - LinkedList q = new LinkedList(); + LinkedList q = new LinkedList(); assertTrue(q.isEmpty()); - q.add(new Integer(1)); + q.add(one); assertFalse(q.isEmpty()); - q.add(new Integer(2)); + q.add(two); q.remove(); q.remove(); assertTrue(q.isEmpty()); @@ -80,14 +107,14 @@ public class LinkedListTest extends JSR1 * size changes when elements added and removed */ public void testSize() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(SIZE-i, q.size()); + mustEqual(SIZE - i, q.size()); q.remove(); } for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.size()); - q.add(new Integer(i)); + mustEqual(i, q.size()); + mustAdd(q, i); } } @@ -95,27 +122,29 @@ public class LinkedListTest extends JSR1 * offer(null) succeeds */ public void testOfferNull() { - LinkedList q = new LinkedList(); + LinkedList q = new LinkedList(); q.offer(null); + assertNull(q.get(0)); + assertTrue(q.contains(null)); } /** * Offer succeeds */ public void testOffer() { - LinkedList q = new LinkedList(); - assertTrue(q.offer(new Integer(0))); - assertTrue(q.offer(new Integer(1))); + LinkedList q = new LinkedList(); + mustOffer(q, zero); + mustOffer(q, one); } /** * add succeeds */ public void testAdd() { - LinkedList q = new LinkedList(); + LinkedList q = new LinkedList(); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.size()); - assertTrue(q.add(new Integer(i))); + mustEqual(i, q.size()); + mustAdd(q, i); } } @@ -123,8 +152,8 @@ public class LinkedListTest extends JSR1 * addAll(null) throws NPE */ public void testAddAll1() { + LinkedList q = new LinkedList(); try { - LinkedList q = new LinkedList(); q.addAll(null); shouldThrow(); } catch (NullPointerException success) {} @@ -134,25 +163,23 @@ public class LinkedListTest extends JSR1 * Queue contains all elements, in traversal order, of successful addAll */ public void testAddAll5() { - Integer[] empty = new Integer[0]; - Integer[] ints = new Integer[SIZE]; - for (int i = 0; i < SIZE; ++i) - ints[i] = i; - LinkedList q = new LinkedList(); + Item[] empty = new Item[0]; + Item[] items = defaultItems; + LinkedList q = new LinkedList(); assertFalse(q.addAll(Arrays.asList(empty))); - assertTrue(q.addAll(Arrays.asList(ints))); + assertTrue(q.addAll(Arrays.asList(items))); for (int i = 0; i < SIZE; ++i) - assertEquals(ints[i], q.poll()); + mustEqual(items[i], q.poll()); } /** * addAll with too large an index throws IOOBE */ public void testAddAll2_IndexOutOfBoundsException() { - LinkedList l = new LinkedList(); - l.add(new Object()); - LinkedList m = new LinkedList(); - m.add(new Object()); + LinkedList l = new LinkedList(); + l.add(zero); + LinkedList m = new LinkedList(); + m.add(one); try { l.addAll(4,m); shouldThrow(); @@ -163,10 +190,10 @@ public class LinkedListTest extends JSR1 * addAll with negative index throws IOOBE */ public void testAddAll4_BadIndex() { - LinkedList l = new LinkedList(); - l.add(new Object()); - LinkedList m = new LinkedList(); - m.add(new Object()); + LinkedList l = new LinkedList(); + l.add(zero); + LinkedList m = new LinkedList(); + m.add(one); try { l.addAll(-1,m); shouldThrow(); @@ -177,9 +204,9 @@ public class LinkedListTest extends JSR1 * poll succeeds unless empty */ public void testPoll() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.poll()); + mustEqual(i, q.poll()); } assertNull(q.poll()); } @@ -188,10 +215,10 @@ public class LinkedListTest extends JSR1 * peek returns next element, or null if empty */ public void testPeek() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.peek()); - assertEquals(i, q.poll()); + mustEqual(i, q.peek()); + mustEqual(i, q.poll()); assertTrue(q.peek() == null || !q.peek().equals(i)); } @@ -202,10 +229,10 @@ public class LinkedListTest extends JSR1 * element returns next element, or throws NSEE if empty */ public void testElement() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.element()); - assertEquals(i, q.poll()); + mustEqual(i, q.element()); + mustEqual(i, q.poll()); } try { q.element(); @@ -217,9 +244,9 @@ public class LinkedListTest extends JSR1 * remove removes next element, or throws NSEE if empty */ public void testRemove() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.remove()); + mustEqual(i, q.remove()); } try { q.remove(); @@ -231,13 +258,19 @@ public class LinkedListTest extends JSR1 * remove(x) removes x and returns true if present */ public void testRemoveElement() { - LinkedList q = populatedQueue(SIZE); - for (int i = 1; i < SIZE; i+=2) { - assertTrue(q.remove(new Integer(i))); - } - for (int i = 0; i < SIZE; i+=2) { - assertTrue(q.remove(new Integer(i))); - assertFalse(q.remove(new Integer(i+1))); + LinkedList q = populatedQueue(SIZE); + for (int i = 1; i < SIZE; i += 2) { + mustContain(q, i); + mustRemove(q, i); + mustNotContain(q, i); + mustContain(q, i - 1); + } + for (int i = 0; i < SIZE; i += 2) { + mustContain(q, i); + mustRemove(q, i); + mustNotContain(q, i); + mustNotRemove(q, i + 1); + mustNotContain(q, i + 1); } assertTrue(q.isEmpty()); } @@ -246,11 +279,11 @@ public class LinkedListTest extends JSR1 * contains(x) reports true when elements added but not yet removed */ public void testContains() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertTrue(q.contains(new Integer(i))); + mustContain(q, i); q.poll(); - assertFalse(q.contains(new Integer(i))); + mustNotContain(q, i); } } @@ -258,11 +291,11 @@ public class LinkedListTest extends JSR1 * clear removes all elements */ public void testClear() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); q.clear(); assertTrue(q.isEmpty()); - assertEquals(0, q.size()); - assertTrue(q.add(new Integer(1))); + mustEqual(0, q.size()); + mustAdd(q, one); assertFalse(q.isEmpty()); q.clear(); assertTrue(q.isEmpty()); @@ -272,12 +305,12 @@ public class LinkedListTest extends JSR1 * containsAll(c) is true when c contains a subset of elements */ public void testContainsAll() { - LinkedList q = populatedQueue(SIZE); - LinkedList p = new LinkedList(); + LinkedList q = populatedQueue(SIZE); + LinkedList p = new LinkedList(); for (int i = 0; i < SIZE; ++i) { assertTrue(q.containsAll(p)); assertFalse(p.containsAll(q)); - assertTrue(p.add(new Integer(i))); + mustAdd(p, i); } assertTrue(p.containsAll(q)); } @@ -286,8 +319,8 @@ public class LinkedListTest extends JSR1 * retainAll(c) retains only those elements of c and reports true if changed */ public void testRetainAll() { - LinkedList q = populatedQueue(SIZE); - LinkedList p = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); + LinkedList p = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { boolean changed = q.retainAll(p); if (i == 0) @@ -296,7 +329,7 @@ public class LinkedListTest extends JSR1 assertTrue(changed); assertTrue(q.containsAll(p)); - assertEquals(SIZE-i, q.size()); + mustEqual(SIZE - i, q.size()); p.remove(); } } @@ -306,48 +339,49 @@ public class LinkedListTest extends JSR1 */ public void testRemoveAll() { for (int i = 1; i < SIZE; ++i) { - LinkedList q = populatedQueue(SIZE); - LinkedList p = populatedQueue(i); + LinkedList q = populatedQueue(SIZE); + LinkedList p = populatedQueue(i); assertTrue(q.removeAll(p)); - assertEquals(SIZE-i, q.size()); + mustEqual(SIZE - i, q.size()); for (int j = 0; j < i; ++j) { - Integer I = (Integer)(p.remove()); - assertFalse(q.contains(I)); + mustNotContain(q, p.remove()); } } } /** - * toArray contains all elements + * toArray contains all elements in FIFO order */ public void testToArray() { - LinkedList q = populatedQueue(SIZE); - Object[] o = q.toArray(); - Arrays.sort(o); - for (int i = 0; i < o.length; i++) - assertEquals(o[i], q.poll()); + LinkedList q = populatedQueue(SIZE); + Object[] a = q.toArray(); + assertSame(Object[].class, a.getClass()); + for (Object o : a) + assertSame(o, q.poll()); + assertTrue(q.isEmpty()); } /** - * toArray(a) contains all elements + * toArray(a) contains all elements in FIFO order */ public void testToArray2() { - LinkedList q = populatedQueue(SIZE); - Integer[] ints = new Integer[SIZE]; - ints = (Integer[])q.toArray(ints); - Arrays.sort(ints); - for (int i = 0; i < ints.length; i++) - assertEquals(ints[i], q.poll()); + LinkedList q = populatedQueue(SIZE); + Item[] items = new Item[SIZE]; + Item[] array = q.toArray(items); + assertSame(items, array); + for (Item o : items) + assertSame(o, q.poll()); + assertTrue(q.isEmpty()); } /** - * toArray(null) throws NPE + * toArray(null) throws NullPointerException */ - public void testToArray_BadArg() { - LinkedList l = new LinkedList(); - l.add(new Object()); + public void testToArray_NullArg() { + LinkedList l = new LinkedList(); + l.add(zero); try { - Object o[] = l.toArray(null); + l.toArray((Item[])null); shouldThrow(); } catch (NullPointerException success) {} } @@ -356,8 +390,8 @@ public class LinkedListTest extends JSR1 * toArray(incompatible array type) throws ArrayStoreException */ public void testToArray1_BadArg() { - LinkedList l = new LinkedList(); - l.add(new Integer(5)); + LinkedList l = new LinkedList(); + l.add(five); try { l.toArray(new String[10]); shouldThrow(); @@ -368,46 +402,52 @@ public class LinkedListTest extends JSR1 * iterator iterates through all elements */ public void testIterator() { - LinkedList q = populatedQueue(SIZE); - int i = 0; - Iterator it = q.iterator(); - while (it.hasNext()) { - assertTrue(q.contains(it.next())); - ++i; - } - assertEquals(i, SIZE); + LinkedList q = populatedQueue(SIZE); + Iterator it = q.iterator(); + int i; + for (i = 0; it.hasNext(); i++) + mustContain(q, it.next()); + mustEqual(i, SIZE); + assertIteratorExhausted(it); + } + + /** + * iterator of empty collection has no elements + */ + public void testEmptyIterator() { + assertIteratorExhausted(new LinkedList().iterator()); } /** * iterator ordering is FIFO */ public void testIteratorOrdering() { - final LinkedList q = new LinkedList(); - q.add(new Integer(1)); - q.add(new Integer(2)); - q.add(new Integer(3)); + final LinkedList q = new LinkedList(); + q.add(one); + q.add(two); + q.add(three); int k = 0; - for (Iterator it = q.iterator(); it.hasNext();) { - assertEquals(++k, it.next()); + for (Iterator it = q.iterator(); it.hasNext();) { + mustEqual(++k, it.next()); } - assertEquals(3, k); + mustEqual(3, k); } /** * iterator.remove removes current element */ public void testIteratorRemove() { - final LinkedList q = new LinkedList(); - q.add(new Integer(1)); - q.add(new Integer(2)); - q.add(new Integer(3)); - Iterator it = q.iterator(); - assertEquals(it.next(), 1); + final LinkedList q = new LinkedList(); + q.add(one); + q.add(two); + q.add(three); + Iterator it = q.iterator(); + mustEqual(1, it.next()); it.remove(); it = q.iterator(); - assertEquals(it.next(), 2); - assertEquals(it.next(), 3); + mustEqual(2, it.next()); + mustEqual(3, it.next()); assertFalse(it.hasNext()); } @@ -415,14 +455,14 @@ public class LinkedListTest extends JSR1 * Descending iterator iterates through all elements */ public void testDescendingIterator() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); int i = 0; - Iterator it = q.descendingIterator(); + Iterator it = q.descendingIterator(); while (it.hasNext()) { - assertTrue(q.contains(it.next())); + mustContain(q, it.next()); ++i; } - assertEquals(i, SIZE); + mustEqual(i, SIZE); assertFalse(it.hasNext()); try { it.next(); @@ -434,27 +474,27 @@ public class LinkedListTest extends JSR1 * Descending iterator ordering is reverse FIFO */ public void testDescendingIteratorOrdering() { - final LinkedList q = new LinkedList(); - q.add(new Integer(3)); - q.add(new Integer(2)); - q.add(new Integer(1)); + final LinkedList q = new LinkedList(); + q.add(three); + q.add(two); + q.add(one); int k = 0; - for (Iterator it = q.descendingIterator(); it.hasNext();) { - assertEquals(++k, it.next()); + for (Iterator it = q.descendingIterator(); it.hasNext();) { + mustEqual(++k, it.next()); } - assertEquals(3, k); + mustEqual(3, k); } /** * descendingIterator.remove removes current element */ public void testDescendingIteratorRemove() { - final LinkedList q = new LinkedList(); + final LinkedList q = new LinkedList(); q.add(three); q.add(two); q.add(one); - Iterator it = q.descendingIterator(); + Iterator it = q.descendingIterator(); it.next(); it.remove(); it = q.descendingIterator(); @@ -463,15 +503,14 @@ public class LinkedListTest extends JSR1 assertFalse(it.hasNext()); } - /** * toString contains toStrings of elements */ public void testToString() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); String s = q.toString(); for (int i = 0; i < SIZE; ++i) { - assertTrue(s.indexOf(String.valueOf(i)) >= 0); + assertTrue(s.contains(String.valueOf(i))); } } @@ -479,7 +518,7 @@ public class LinkedListTest extends JSR1 * peek returns element inserted with addFirst */ public void testAddFirst() { - LinkedList q = populatedQueue(3); + LinkedList q = populatedQueue(3); q.addFirst(four); assertSame(four, q.peek()); } @@ -488,7 +527,7 @@ public class LinkedListTest extends JSR1 * peekFirst returns element inserted with push */ public void testPush() { - LinkedList q = populatedQueue(3); + LinkedList q = populatedQueue(3); q.push(four); assertSame(four, q.peekFirst()); } @@ -497,9 +536,9 @@ public class LinkedListTest extends JSR1 * pop removes next element, or throws NSEE if empty */ public void testPop() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.pop()); + mustEqual(i, q.pop()); } try { q.pop(); @@ -511,27 +550,27 @@ public class LinkedListTest extends JSR1 * OfferFirst succeeds */ public void testOfferFirst() { - LinkedList q = new LinkedList(); - assertTrue(q.offerFirst(new Integer(0))); - assertTrue(q.offerFirst(new Integer(1))); + LinkedList q = new LinkedList(); + assertTrue(q.offerFirst(zero)); + assertTrue(q.offerFirst(one)); } /** * OfferLast succeeds */ public void testOfferLast() { - LinkedList q = new LinkedList(); - assertTrue(q.offerLast(new Integer(0))); - assertTrue(q.offerLast(new Integer(1))); + LinkedList q = new LinkedList(); + assertTrue(q.offerLast(zero)); + assertTrue(q.offerLast(one)); } /** * pollLast succeeds unless empty */ public void testPollLast() { - LinkedList q = populatedQueue(SIZE); - for (int i = SIZE-1; i >= 0; --i) { - assertEquals(i, q.pollLast()); + LinkedList q = populatedQueue(SIZE); + for (int i = SIZE - 1; i >= 0; --i) { + mustEqual(i, q.pollLast()); } assertNull(q.pollLast()); } @@ -540,25 +579,24 @@ public class LinkedListTest extends JSR1 * peekFirst returns next element, or null if empty */ public void testPeekFirst() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.peekFirst()); - assertEquals(i, q.pollFirst()); + mustEqual(i, q.peekFirst()); + mustEqual(i, q.pollFirst()); assertTrue(q.peekFirst() == null || !q.peekFirst().equals(i)); } assertNull(q.peekFirst()); } - /** * peekLast returns next element, or null if empty */ public void testPeekLast() { - LinkedList q = populatedQueue(SIZE); - for (int i = SIZE-1; i >= 0; --i) { - assertEquals(i, q.peekLast()); - assertEquals(i, q.pollLast()); + LinkedList q = populatedQueue(SIZE); + for (int i = SIZE - 1; i >= 0; --i) { + mustEqual(i, q.peekLast()); + mustEqual(i, q.pollLast()); assertTrue(q.peekLast() == null || !q.peekLast().equals(i)); } @@ -566,10 +604,10 @@ public class LinkedListTest extends JSR1 } public void testFirstElement() { - LinkedList q = populatedQueue(SIZE); + LinkedList q = populatedQueue(SIZE); for (int i = 0; i < SIZE; ++i) { - assertEquals(i, q.getFirst()); - assertEquals(i, q.pollFirst()); + mustEqual(i, q.getFirst()); + mustEqual(i, q.pollFirst()); } try { q.getFirst(); @@ -581,10 +619,10 @@ public class LinkedListTest extends JSR1 * getLast returns next element, or throws NSEE if empty */ public void testLastElement() { - LinkedList q = populatedQueue(SIZE); - for (int i = SIZE-1; i >= 0; --i) { - assertEquals(i, q.getLast()); - assertEquals(i, q.pollLast()); + LinkedList q = populatedQueue(SIZE); + for (int i = SIZE - 1; i >= 0; --i) { + mustEqual(i, q.getLast()); + mustEqual(i, q.pollLast()); } try { q.getLast(); @@ -597,13 +635,13 @@ public class LinkedListTest extends JSR1 * removeFirstOccurrence(x) removes x and returns true if present */ public void testRemoveFirstOccurrence() { - LinkedList q = populatedQueue(SIZE); - for (int i = 1; i < SIZE; i+=2) { - assertTrue(q.removeFirstOccurrence(new Integer(i))); - } - for (int i = 0; i < SIZE; i+=2) { - assertTrue(q.removeFirstOccurrence(new Integer(i))); - assertFalse(q.removeFirstOccurrence(new Integer(i+1))); + LinkedList q = populatedQueue(SIZE); + for (int i = 1; i < SIZE; i += 2) { + assertTrue(q.removeFirstOccurrence(itemFor(i))); + } + for (int i = 0; i < SIZE; i += 2) { + assertTrue(q.removeFirstOccurrence(itemFor(i))); + assertFalse(q.removeFirstOccurrence(itemFor(i + 1))); } assertTrue(q.isEmpty()); } @@ -612,13 +650,13 @@ public class LinkedListTest extends JSR1 * removeLastOccurrence(x) removes x and returns true if present */ public void testRemoveLastOccurrence() { - LinkedList q = populatedQueue(SIZE); - for (int i = 1; i < SIZE; i+=2) { - assertTrue(q.removeLastOccurrence(new Integer(i))); - } - for (int i = 0; i < SIZE; i+=2) { - assertTrue(q.removeLastOccurrence(new Integer(i))); - assertFalse(q.removeLastOccurrence(new Integer(i+1))); + LinkedList q = populatedQueue(SIZE); + for (int i = 1; i < SIZE; i += 2) { + assertTrue(q.removeLastOccurrence(itemFor(i))); + } + for (int i = 0; i < SIZE; i += 2) { + assertTrue(q.removeLastOccurrence(itemFor(i))); + assertFalse(q.removeLastOccurrence(itemFor(i + 1))); } assertTrue(q.isEmpty()); }