public void testSimpleHashMap() {
final WeakIdentityMap<String, String> map = WeakIdentityMap.newHashMap(random().nextBoolean());
// we keep strong references to the keys,
// so WeakIdentityMap will not forget about them:
String key1 = new String("foo");
String key2 = new String("foo");
String key3 = new String("foo");
assertNotSame(key1, key2);
assertEquals(key1, key2);
assertNotSame(key1, key3);
assertEquals(key1, key3);
assertNotSame(key2, key3);
assertEquals(key2, key3);
// try null key & check its iterator also return null:
map.put(null, "null");
{
Iterator<String> it = map.keyIterator();
assertTrue(it.hasNext());
assertNull(it.next());
assertFalse(it.hasNext());
assertFalse(it.hasNext());
}
// 2 more keys:
map.put(key1, "bar1");
map.put(key2, "bar2");
assertEquals(3, map.size());
assertEquals("bar1", map.get(key1));
assertEquals("bar2", map.get(key2));
assertEquals(null, map.get(key3));
assertEquals("null", map.get(null));
assertTrue(map.containsKey(key1));
assertTrue(map.containsKey(key2));
assertFalse(map.containsKey(key3));
assertTrue(map.containsKey(null));
// repeat and check that we have no double entries
map.put(key1, "bar1");
map.put(key2, "bar2");
map.put(null, "null");
assertEquals(3, map.size());
assertEquals("bar1", map.get(key1));
assertEquals("bar2", map.get(key2));
assertEquals(null, map.get(key3));
assertEquals("null", map.get(null));
assertTrue(map.containsKey(key1));
assertTrue(map.containsKey(key2));
assertFalse(map.containsKey(key3));
assertTrue(map.containsKey(null));
map.remove(null);
assertEquals(2, map.size());
map.remove(key1);
assertEquals(1, map.size());
map.put(key1, "bar1");
map.put(key2, "bar2");
map.put(key3, "bar3");
assertEquals(3, map.size());
int c = 0, keysAssigned = 0;
for (Iterator<String> it = map.keyIterator(); it.hasNext(); ) {
assertTrue(it.hasNext()); // try again, should return same result!
final String k = it.next();
assertTrue(k == key1 || k == key2 | k == key3);
keysAssigned += (k == key1) ? 1 : ((k == key2) ? 2 : 4);
c++;
}
assertEquals(3, c);
assertEquals("all keys must have been seen", 1 + 2 + 4, keysAssigned);
c = 0;
for (Iterator<String> it = map.valueIterator(); it.hasNext(); ) {
final String v = it.next();
assertTrue(v.startsWith("bar"));
c++;
}
assertEquals(3, c);
// clear strong refs
key1 = key2 = key3 = null;
// check that GC does not cause problems in reap() method, wait 1 second and let GC work:
int size = map.size();
for (int i = 0; size > 0 && i < 10; i++)
try {
System.runFinalization();
System.gc();
int newSize = map.size();
assertTrue("previousSize(" + size + ")>=newSize(" + newSize + ")", size >= newSize);
size = newSize;
Thread.sleep(100L);
c = 0;
for (Iterator<String> it = map.keyIterator(); it.hasNext(); ) {
assertNotNull(it.next());
c++;
}
newSize = map.size();
assertTrue("previousSize(" + size + ")>=iteratorSize(" + c + ")", size >= c);
assertTrue("iteratorSize(" + c + ")>=newSize(" + newSize + ")", c >= newSize);
size = newSize;
} catch (InterruptedException ie) {
}
map.clear();
assertEquals(0, map.size());
assertTrue(map.isEmpty());
Iterator<String> it = map.keyIterator();
assertFalse(it.hasNext());
try {
it.next();
fail("Should throw NoSuchElementException");
} catch (NoSuchElementException nse) {
}
key1 = new String("foo");
key2 = new String("foo");
map.put(key1, "bar1");
map.put(key2, "bar2");
assertEquals(2, map.size());
map.clear();
assertEquals(0, map.size());
assertTrue(map.isEmpty());
}
public void testConcurrentHashMap() throws Exception {
// don't make threadCount and keyCount random, otherwise easily OOMs or fails otherwise:
final int threadCount = 8, keyCount = 1024;
final ExecutorService exec =
Executors.newFixedThreadPool(threadCount, new NamedThreadFactory("testConcurrentHashMap"));
final WeakIdentityMap<Object, Integer> map =
WeakIdentityMap.newConcurrentHashMap(random().nextBoolean());
// we keep strong references to the keys,
// so WeakIdentityMap will not forget about them:
final AtomicReferenceArray<Object> keys = new AtomicReferenceArray<Object>(keyCount);
for (int j = 0; j < keyCount; j++) {
keys.set(j, new Object());
}
try {
for (int t = 0; t < threadCount; t++) {
final Random rnd = new Random(random().nextLong());
exec.execute(
new Runnable() {
@Override
public void run() {
final int count = atLeast(rnd, 10000);
for (int i = 0; i < count; i++) {
final int j = rnd.nextInt(keyCount);
switch (rnd.nextInt(5)) {
case 0:
map.put(keys.get(j), Integer.valueOf(j));
break;
case 1:
final Integer v = map.get(keys.get(j));
if (v != null) {
assertEquals(j, v.intValue());
}
break;
case 2:
map.remove(keys.get(j));
break;
case 3:
// renew key, the old one will be GCed at some time:
keys.set(j, new Object());
break;
case 4:
// check iterator still working
for (Iterator<Object> it = map.keyIterator(); it.hasNext(); ) {
assertNotNull(it.next());
}
break;
default:
fail("Should not get here.");
}
}
}
});
}
} finally {
exec.shutdown();
while (!exec.awaitTermination(1000L, TimeUnit.MILLISECONDS)) ;
}
// clear strong refs
for (int j = 0; j < keyCount; j++) {
keys.set(j, null);
}
// check that GC does not cause problems in reap() method:
int size = map.size();
for (int i = 0; size > 0 && i < 10; i++)
try {
System.runFinalization();
System.gc();
int newSize = map.size();
assertTrue("previousSize(" + size + ")>=newSize(" + newSize + ")", size >= newSize);
size = newSize;
Thread.sleep(100L);
int c = 0;
for (Iterator<Object> it = map.keyIterator(); it.hasNext(); ) {
assertNotNull(it.next());
c++;
}
newSize = map.size();
assertTrue("previousSize(" + size + ")>=iteratorSize(" + c + ")", size >= c);
assertTrue("iteratorSize(" + c + ")>=newSize(" + newSize + ")", c >= newSize);
size = newSize;
} catch (InterruptedException ie) {
}
}