/** Returns a new queue of given size containing consecutive PDelays 0 ... n. */
private DelayQueue<PDelay> populatedQueue(int n) {
DelayQueue<PDelay> q = new DelayQueue<PDelay>();
assertTrue(q.isEmpty());
for (int i = n - 1; i >= 0; i -= 2) assertTrue(q.offer(new PDelay(i)));
for (int i = (n & 1); i < n; i += 2) assertTrue(q.offer(new PDelay(i)));
assertFalse(q.isEmpty());
assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
assertEquals(n, q.size());
return q;
}
/** isEmpty is true before add, false after */
public void testEmpty() {
DelayQueue q = new DelayQueue();
assertTrue(q.isEmpty());
assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
q.add(new PDelay(1));
assertFalse(q.isEmpty());
q.add(new PDelay(2));
q.remove();
q.remove();
assertTrue(q.isEmpty());
}
/** clear removes all elements */
public void testClear() {
DelayQueue q = populatedQueue(SIZE);
q.clear();
assertTrue(q.isEmpty());
assertEquals(0, q.size());
assertEquals(Integer.MAX_VALUE, q.remainingCapacity());
PDelay x = new PDelay(1);
q.add(x);
assertFalse(q.isEmpty());
assertTrue(q.contains(x));
q.clear();
assertTrue(q.isEmpty());
}
/** peek returns next element, or null if empty */
public void testPeek() {
DelayQueue q = populatedQueue(SIZE);
for (int i = 0; i < SIZE; ++i) {
assertEquals(new PDelay(i), q.peek());
assertEquals(new PDelay(i), q.poll());
if (q.isEmpty()) assertNull(q.peek());
else assertFalse(new PDelay(i).equals(q.peek()));
}
assertNull(q.peek());
}
/** Delayed actions do not occur until their delay elapses */
public void testDelay() throws InterruptedException {
DelayQueue<NanoDelay> q = new DelayQueue<NanoDelay>();
for (int i = 0; i < SIZE; ++i) q.add(new NanoDelay(1000000L * (SIZE - i)));
long last = 0;
for (int i = 0; i < SIZE; ++i) {
NanoDelay e = q.take();
long tt = e.getTriggerTime();
assertTrue(System.nanoTime() - tt >= 0);
if (i != 0) assertTrue(tt >= last);
last = tt;
}
assertTrue(q.isEmpty());
}
/** drainTo(c) empties queue into another collection c */
public void testDrainTo() {
DelayQueue q = new DelayQueue();
PDelay[] elems = new PDelay[SIZE];
for (int i = 0; i < SIZE; ++i) {
elems[i] = new PDelay(i);
q.add(elems[i]);
}
ArrayList l = new ArrayList();
q.drainTo(l);
assertEquals(0, q.size());
for (int i = 0; i < SIZE; ++i) assertEquals(elems[i], l.get(i));
q.add(elems[0]);
q.add(elems[1]);
assertFalse(q.isEmpty());
assertTrue(q.contains(elems[0]));
assertTrue(q.contains(elems[1]));
l.clear();
q.drainTo(l);
assertEquals(0, q.size());
assertEquals(2, l.size());
for (int i = 0; i < 2; ++i) assertEquals(elems[i], l.get(i));
}