| /* |
| * 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/publicdomain/zero/1.0/ |
| * Other contributors include Andrew Wright, Jeffrey Hayes, |
| * Pat Fisher, Mike Judd. |
| */ |
| |
| package jsr166; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Enumeration; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.Random; |
| import java.util.Set; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import junit.framework.Test; |
| import junit.framework.TestSuite; |
| |
| public class ConcurrentHashMapTest extends JSR166TestCase { |
| // android-note: Removed because the CTS runner does a bad job of |
| // retrying tests that have suite() declarations. |
| // |
| // public static void main(String[] args) { |
| // main(suite(), args); |
| // } |
| // public static Test suite() { |
| // return new TestSuite(...); |
| // } |
| |
| /** |
| * Returns a new map from Integers 1-5 to Strings "A"-"E". |
| */ |
| private static ConcurrentHashMap<Integer, String> map5() { |
| ConcurrentHashMap map = new ConcurrentHashMap<Integer, String>(5); |
| assertTrue(map.isEmpty()); |
| map.put(one, "A"); |
| map.put(two, "B"); |
| map.put(three, "C"); |
| map.put(four, "D"); |
| map.put(five, "E"); |
| assertFalse(map.isEmpty()); |
| assertEquals(5, map.size()); |
| return map; |
| } |
| |
| /** Re-implement Integer.compare for old java versions */ |
| static int compare(int x, int y) { return x < y ? -1 : x > y ? 1 : 0; } |
| |
| // classes for testing Comparable fallbacks |
| static class BI implements Comparable<BI> { |
| private final int value; |
| BI(int value) { this.value = value; } |
| public int compareTo(BI other) { |
| return compare(value, other.value); |
| } |
| public boolean equals(Object x) { |
| return (x instanceof BI) && ((BI)x).value == value; |
| } |
| public int hashCode() { return 42; } |
| } |
| static class CI extends BI { CI(int value) { super(value); } } |
| static class DI extends BI { DI(int value) { super(value); } } |
| |
| static class BS implements Comparable<BS> { |
| private final String value; |
| BS(String value) { this.value = value; } |
| public int compareTo(BS other) { |
| return value.compareTo(other.value); |
| } |
| public boolean equals(Object x) { |
| return (x instanceof BS) && value.equals(((BS)x).value); |
| } |
| public int hashCode() { return 42; } |
| } |
| |
| static class LexicographicList<E extends Comparable<E>> extends ArrayList<E> |
| implements Comparable<LexicographicList<E>> { |
| LexicographicList(Collection<E> c) { super(c); } |
| LexicographicList(E e) { super(Collections.singleton(e)); } |
| public int compareTo(LexicographicList<E> other) { |
| int common = Math.min(size(), other.size()); |
| int r = 0; |
| for (int i = 0; i < common; i++) { |
| if ((r = get(i).compareTo(other.get(i))) != 0) |
| break; |
| } |
| if (r == 0) |
| r = compare(size(), other.size()); |
| return r; |
| } |
| private static final long serialVersionUID = 0; |
| } |
| |
| static class CollidingObject { |
| final String value; |
| CollidingObject(final String value) { this.value = value; } |
| public int hashCode() { return this.value.hashCode() & 1; } |
| public boolean equals(final Object obj) { |
| return (obj instanceof CollidingObject) && ((CollidingObject)obj).value.equals(value); |
| } |
| } |
| |
| static class ComparableCollidingObject extends CollidingObject implements Comparable<ComparableCollidingObject> { |
| ComparableCollidingObject(final String value) { super(value); } |
| public int compareTo(final ComparableCollidingObject o) { |
| return value.compareTo(o.value); |
| } |
| } |
| |
| /** |
| * Inserted elements that are subclasses of the same Comparable |
| * class are found. |
| */ |
| public void testComparableFamily() { |
| int size = 500; // makes measured test run time -> 60ms |
| ConcurrentHashMap<BI, Boolean> m = |
| new ConcurrentHashMap<BI, Boolean>(); |
| for (int i = 0; i < size; i++) { |
| assertTrue(m.put(new CI(i), true) == null); |
| } |
| for (int i = 0; i < size; i++) { |
| assertTrue(m.containsKey(new CI(i))); |
| assertTrue(m.containsKey(new DI(i))); |
| } |
| } |
| |
| /** |
| * Elements of classes with erased generic type parameters based |
| * on Comparable can be inserted and found. |
| */ |
| public void testGenericComparable() { |
| int size = 120; // makes measured test run time -> 60ms |
| ConcurrentHashMap<Object, Boolean> m = |
| new ConcurrentHashMap<Object, Boolean>(); |
| for (int i = 0; i < size; i++) { |
| BI bi = new BI(i); |
| BS bs = new BS(String.valueOf(i)); |
| LexicographicList<BI> bis = new LexicographicList<BI>(bi); |
| LexicographicList<BS> bss = new LexicographicList<BS>(bs); |
| assertTrue(m.putIfAbsent(bis, true) == null); |
| assertTrue(m.containsKey(bis)); |
| if (m.putIfAbsent(bss, true) == null) |
| assertTrue(m.containsKey(bss)); |
| assertTrue(m.containsKey(bis)); |
| } |
| for (int i = 0; i < size; i++) { |
| assertTrue(m.containsKey(Collections.singletonList(new BI(i)))); |
| } |
| } |
| |
| /** |
| * Elements of non-comparable classes equal to those of classes |
| * with erased generic type parameters based on Comparable can be |
| * inserted and found. |
| */ |
| public void testGenericComparable2() { |
| int size = 500; // makes measured test run time -> 60ms |
| ConcurrentHashMap<Object, Boolean> m = |
| new ConcurrentHashMap<Object, Boolean>(); |
| for (int i = 0; i < size; i++) { |
| m.put(Collections.singletonList(new BI(i)), true); |
| } |
| |
| for (int i = 0; i < size; i++) { |
| LexicographicList<BI> bis = new LexicographicList<BI>(new BI(i)); |
| assertTrue(m.containsKey(bis)); |
| } |
| } |
| |
| /** |
| * Mixtures of instances of comparable and non-comparable classes |
| * can be inserted and found. |
| */ |
| public void testMixedComparable() { |
| int size = 1200; // makes measured test run time -> 35ms |
| ConcurrentHashMap<Object, Object> map = |
| new ConcurrentHashMap<Object, Object>(); |
| Random rng = new Random(); |
| for (int i = 0; i < size; i++) { |
| Object x; |
| switch (rng.nextInt(4)) { |
| case 0: |
| x = new Object(); |
| break; |
| case 1: |
| x = new CollidingObject(Integer.toString(i)); |
| break; |
| default: |
| x = new ComparableCollidingObject(Integer.toString(i)); |
| } |
| assertNull(map.put(x, x)); |
| } |
| int count = 0; |
| for (Object k : map.keySet()) { |
| assertEquals(map.get(k), k); |
| ++count; |
| } |
| assertEquals(count, size); |
| assertEquals(map.size(), size); |
| for (Object k : map.keySet()) { |
| assertEquals(map.put(k, k), k); |
| } |
| } |
| |
| /** |
| * clear removes all pairs |
| */ |
| public void testClear() { |
| ConcurrentHashMap map = map5(); |
| map.clear(); |
| assertEquals(0, map.size()); |
| } |
| |
| /** |
| * Maps with same contents are equal |
| */ |
| public void testEquals() { |
| ConcurrentHashMap map1 = map5(); |
| ConcurrentHashMap map2 = map5(); |
| assertEquals(map1, map2); |
| assertEquals(map2, map1); |
| map1.clear(); |
| assertFalse(map1.equals(map2)); |
| assertFalse(map2.equals(map1)); |
| } |
| |
| /** |
| * hashCode() equals sum of each key.hashCode ^ value.hashCode |
| */ |
| public void testHashCode() { |
| ConcurrentHashMap<Integer,String> map = map5(); |
| int sum = 0; |
| for (Map.Entry<Integer,String> e : map.entrySet()) |
| sum += e.getKey().hashCode() ^ e.getValue().hashCode(); |
| assertEquals(sum, map.hashCode()); |
| } |
| |
| /** |
| * contains returns true for contained value |
| */ |
| public void testContains() { |
| ConcurrentHashMap map = map5(); |
| assertTrue(map.contains("A")); |
| assertFalse(map.contains("Z")); |
| } |
| |
| /** |
| * containsKey returns true for contained key |
| */ |
| public void testContainsKey() { |
| ConcurrentHashMap map = map5(); |
| assertTrue(map.containsKey(one)); |
| assertFalse(map.containsKey(zero)); |
| } |
| |
| /** |
| * containsValue returns true for held values |
| */ |
| public void testContainsValue() { |
| ConcurrentHashMap map = map5(); |
| assertTrue(map.containsValue("A")); |
| assertFalse(map.containsValue("Z")); |
| } |
| |
| /** |
| * enumeration returns an enumeration containing the correct |
| * elements |
| */ |
| public void testEnumeration() { |
| ConcurrentHashMap map = map5(); |
| Enumeration e = map.elements(); |
| int count = 0; |
| while (e.hasMoreElements()) { |
| count++; |
| e.nextElement(); |
| } |
| assertEquals(5, count); |
| } |
| |
| /** |
| * get returns the correct element at the given key, |
| * or null if not present |
| */ |
| public void testGet() { |
| ConcurrentHashMap map = map5(); |
| assertEquals("A", (String)map.get(one)); |
| ConcurrentHashMap empty = new ConcurrentHashMap(); |
| assertNull(map.get("anything")); |
| assertNull(empty.get("anything")); |
| } |
| |
| /** |
| * isEmpty is true of empty map and false for non-empty |
| */ |
| public void testIsEmpty() { |
| ConcurrentHashMap empty = new ConcurrentHashMap(); |
| ConcurrentHashMap map = map5(); |
| assertTrue(empty.isEmpty()); |
| assertFalse(map.isEmpty()); |
| } |
| |
| /** |
| * keys returns an enumeration containing all the keys from the map |
| */ |
| public void testKeys() { |
| ConcurrentHashMap map = map5(); |
| Enumeration e = map.keys(); |
| int count = 0; |
| while (e.hasMoreElements()) { |
| count++; |
| e.nextElement(); |
| } |
| assertEquals(5, count); |
| } |
| |
| /** |
| * keySet returns a Set containing all the keys |
| */ |
| public void testKeySet() { |
| ConcurrentHashMap map = map5(); |
| Set s = map.keySet(); |
| assertEquals(5, s.size()); |
| assertTrue(s.contains(one)); |
| assertTrue(s.contains(two)); |
| assertTrue(s.contains(three)); |
| assertTrue(s.contains(four)); |
| assertTrue(s.contains(five)); |
| } |
| |
| /** |
| * keySet.toArray returns contains all keys |
| */ |
| public void testKeySetToArray() { |
| ConcurrentHashMap map = map5(); |
| Set s = map.keySet(); |
| Object[] ar = s.toArray(); |
| assertTrue(s.containsAll(Arrays.asList(ar))); |
| assertEquals(5, ar.length); |
| ar[0] = m10; |
| assertFalse(s.containsAll(Arrays.asList(ar))); |
| } |
| |
| /** |
| * Values.toArray contains all values |
| */ |
| public void testValuesToArray() { |
| ConcurrentHashMap map = map5(); |
| Collection v = map.values(); |
| Object[] ar = v.toArray(); |
| ArrayList s = new ArrayList(Arrays.asList(ar)); |
| assertEquals(5, ar.length); |
| assertTrue(s.contains("A")); |
| assertTrue(s.contains("B")); |
| assertTrue(s.contains("C")); |
| assertTrue(s.contains("D")); |
| assertTrue(s.contains("E")); |
| } |
| |
| /** |
| * entrySet.toArray contains all entries |
| */ |
| public void testEntrySetToArray() { |
| ConcurrentHashMap map = map5(); |
| Set s = map.entrySet(); |
| Object[] ar = s.toArray(); |
| assertEquals(5, ar.length); |
| for (int i = 0; i < 5; ++i) { |
| assertTrue(map.containsKey(((Map.Entry)(ar[i])).getKey())); |
| assertTrue(map.containsValue(((Map.Entry)(ar[i])).getValue())); |
| } |
| } |
| |
| /** |
| * values collection contains all values |
| */ |
| public void testValues() { |
| ConcurrentHashMap map = map5(); |
| Collection s = map.values(); |
| assertEquals(5, s.size()); |
| assertTrue(s.contains("A")); |
| assertTrue(s.contains("B")); |
| assertTrue(s.contains("C")); |
| assertTrue(s.contains("D")); |
| assertTrue(s.contains("E")); |
| } |
| |
| /** |
| * entrySet contains all pairs |
| */ |
| public void testEntrySet() { |
| ConcurrentHashMap map = map5(); |
| Set s = map.entrySet(); |
| assertEquals(5, s.size()); |
| Iterator it = s.iterator(); |
| while (it.hasNext()) { |
| Map.Entry e = (Map.Entry) it.next(); |
| assertTrue( |
| (e.getKey().equals(one) && e.getValue().equals("A")) || |
| (e.getKey().equals(two) && e.getValue().equals("B")) || |
| (e.getKey().equals(three) && e.getValue().equals("C")) || |
| (e.getKey().equals(four) && e.getValue().equals("D")) || |
| (e.getKey().equals(five) && e.getValue().equals("E"))); |
| } |
| } |
| |
| /** |
| * putAll adds all key-value pairs from the given map |
| */ |
| public void testPutAll() { |
| ConcurrentHashMap empty = new ConcurrentHashMap(); |
| ConcurrentHashMap map = map5(); |
| empty.putAll(map); |
| assertEquals(5, empty.size()); |
| assertTrue(empty.containsKey(one)); |
| assertTrue(empty.containsKey(two)); |
| assertTrue(empty.containsKey(three)); |
| assertTrue(empty.containsKey(four)); |
| assertTrue(empty.containsKey(five)); |
| } |
| |
| /** |
| * putIfAbsent works when the given key is not present |
| */ |
| public void testPutIfAbsent() { |
| ConcurrentHashMap map = map5(); |
| map.putIfAbsent(six, "Z"); |
| assertTrue(map.containsKey(six)); |
| } |
| |
| /** |
| * putIfAbsent does not add the pair if the key is already present |
| */ |
| public void testPutIfAbsent2() { |
| ConcurrentHashMap map = map5(); |
| assertEquals("A", map.putIfAbsent(one, "Z")); |
| } |
| |
| /** |
| * replace fails when the given key is not present |
| */ |
| public void testReplace() { |
| ConcurrentHashMap map = map5(); |
| assertNull(map.replace(six, "Z")); |
| assertFalse(map.containsKey(six)); |
| } |
| |
| /** |
| * replace succeeds if the key is already present |
| */ |
| public void testReplace2() { |
| ConcurrentHashMap map = map5(); |
| assertNotNull(map.replace(one, "Z")); |
| assertEquals("Z", map.get(one)); |
| } |
| |
| /** |
| * replace value fails when the given key not mapped to expected value |
| */ |
| public void testReplaceValue() { |
| ConcurrentHashMap map = map5(); |
| assertEquals("A", map.get(one)); |
| assertFalse(map.replace(one, "Z", "Z")); |
| assertEquals("A", map.get(one)); |
| } |
| |
| /** |
| * replace value succeeds when the given key mapped to expected value |
| */ |
| public void testReplaceValue2() { |
| ConcurrentHashMap map = map5(); |
| assertEquals("A", map.get(one)); |
| assertTrue(map.replace(one, "A", "Z")); |
| assertEquals("Z", map.get(one)); |
| } |
| |
| /** |
| * remove removes the correct key-value pair from the map |
| */ |
| public void testRemove() { |
| ConcurrentHashMap map = map5(); |
| map.remove(five); |
| assertEquals(4, map.size()); |
| assertFalse(map.containsKey(five)); |
| } |
| |
| /** |
| * remove(key,value) removes only if pair present |
| */ |
| public void testRemove2() { |
| ConcurrentHashMap map = map5(); |
| map.remove(five, "E"); |
| assertEquals(4, map.size()); |
| assertFalse(map.containsKey(five)); |
| map.remove(four, "A"); |
| assertEquals(4, map.size()); |
| assertTrue(map.containsKey(four)); |
| } |
| |
| /** |
| * size returns the correct values |
| */ |
| public void testSize() { |
| ConcurrentHashMap map = map5(); |
| ConcurrentHashMap empty = new ConcurrentHashMap(); |
| assertEquals(0, empty.size()); |
| assertEquals(5, map.size()); |
| } |
| |
| /** |
| * toString contains toString of elements |
| */ |
| public void testToString() { |
| ConcurrentHashMap map = map5(); |
| String s = map.toString(); |
| for (int i = 1; i <= 5; ++i) { |
| assertTrue(s.contains(String.valueOf(i))); |
| } |
| } |
| |
| // Exception tests |
| |
| /** |
| * Cannot create with only negative capacity |
| */ |
| public void testConstructor1() { |
| try { |
| new ConcurrentHashMap(-1); |
| shouldThrow(); |
| } catch (IllegalArgumentException success) {} |
| } |
| |
| /** |
| * Constructor (initialCapacity, loadFactor) throws |
| * IllegalArgumentException if either argument is negative |
| */ |
| public void testConstructor2() { |
| try { |
| new ConcurrentHashMap(-1, .75f); |
| shouldThrow(); |
| } catch (IllegalArgumentException success) {} |
| |
| try { |
| new ConcurrentHashMap(16, -1); |
| shouldThrow(); |
| } catch (IllegalArgumentException success) {} |
| } |
| |
| /** |
| * Constructor (initialCapacity, loadFactor, concurrencyLevel) |
| * throws IllegalArgumentException if any argument is negative |
| */ |
| public void testConstructor3() { |
| try { |
| new ConcurrentHashMap(-1, .75f, 1); |
| shouldThrow(); |
| } catch (IllegalArgumentException success) {} |
| |
| try { |
| new ConcurrentHashMap(16, -1, 1); |
| shouldThrow(); |
| } catch (IllegalArgumentException success) {} |
| |
| try { |
| new ConcurrentHashMap(16, .75f, -1); |
| shouldThrow(); |
| } catch (IllegalArgumentException success) {} |
| } |
| |
| /** |
| * ConcurrentHashMap(map) throws NullPointerException if the given |
| * map is null |
| */ |
| public void testConstructor4() { |
| try { |
| new ConcurrentHashMap(null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * ConcurrentHashMap(map) creates a new map with the same mappings |
| * as the given map |
| */ |
| public void testConstructor5() { |
| ConcurrentHashMap map1 = map5(); |
| ConcurrentHashMap map2 = new ConcurrentHashMap(map5()); |
| assertTrue(map2.equals(map1)); |
| map2.put(one, "F"); |
| assertFalse(map2.equals(map1)); |
| } |
| |
| /** |
| * get(null) throws NPE |
| */ |
| public void testGet_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.get(null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * containsKey(null) throws NPE |
| */ |
| public void testContainsKey_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.containsKey(null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * containsValue(null) throws NPE |
| */ |
| public void testContainsValue_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.containsValue(null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * contains(null) throws NPE |
| */ |
| public void testContains_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.contains(null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * put(null,x) throws NPE |
| */ |
| public void testPut1_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.put(null, "whatever"); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * put(x, null) throws NPE |
| */ |
| public void testPut2_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.put("whatever", null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * putIfAbsent(null, x) throws NPE |
| */ |
| public void testPutIfAbsent1_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.putIfAbsent(null, "whatever"); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * replace(null, x) throws NPE |
| */ |
| public void testReplace_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.replace(null, "whatever"); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * replace(null, x, y) throws NPE |
| */ |
| public void testReplaceValue_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.replace(null, one, "whatever"); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * putIfAbsent(x, null) throws NPE |
| */ |
| public void testPutIfAbsent2_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.putIfAbsent("whatever", null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * replace(x, null) throws NPE |
| */ |
| public void testReplace2_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.replace("whatever", null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * replace(x, null, y) throws NPE |
| */ |
| public void testReplaceValue2_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.replace("whatever", null, "A"); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * replace(x, y, null) throws NPE |
| */ |
| public void testReplaceValue3_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| try { |
| c.replace("whatever", one, null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * remove(null) throws NPE |
| */ |
| public void testRemove1_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| c.put("sadsdf", "asdads"); |
| try { |
| c.remove(null); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * remove(null, x) throws NPE |
| */ |
| public void testRemove2_NullPointerException() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| c.put("sadsdf", "asdads"); |
| try { |
| c.remove(null, "whatever"); |
| shouldThrow(); |
| } catch (NullPointerException success) {} |
| } |
| |
| /** |
| * remove(x, null) returns false |
| */ |
| public void testRemove3() { |
| ConcurrentHashMap c = new ConcurrentHashMap(5); |
| c.put("sadsdf", "asdads"); |
| assertFalse(c.remove("sadsdf", null)); |
| } |
| |
| /** |
| * A deserialized map equals original |
| */ |
| public void testSerialization() throws Exception { |
| Map x = map5(); |
| Map y = serialClone(x); |
| |
| assertNotSame(x, y); |
| assertEquals(x.size(), y.size()); |
| assertEquals(x, y); |
| assertEquals(y, x); |
| } |
| |
| /** |
| * SetValue of an EntrySet entry sets value in the map. |
| */ |
| public void testSetValueWriteThrough() { |
| // Adapted from a bug report by Eric Zoerner |
| ConcurrentHashMap map = new ConcurrentHashMap(2, 5.0f, 1); |
| assertTrue(map.isEmpty()); |
| for (int i = 0; i < 20; i++) |
| map.put(new Integer(i), new Integer(i)); |
| assertFalse(map.isEmpty()); |
| Map.Entry entry1 = (Map.Entry)map.entrySet().iterator().next(); |
| // Unless it happens to be first (in which case remainder of |
| // test is skipped), remove a possibly-colliding key from map |
| // which, under some implementations, may cause entry1 to be |
| // cloned in map |
| if (!entry1.getKey().equals(new Integer(16))) { |
| map.remove(new Integer(16)); |
| entry1.setValue("XYZ"); |
| assertTrue(map.containsValue("XYZ")); // fails if write-through broken |
| } |
| } |
| |
| } |