public void testReverse() {
PriorityQueue q = new MinHeap(N);
Item items[] = new Item[N];
for (int i = 0; i < N; i++) {
Item e = new Item(N - i - 1);
q.insert(e);
items[i] = e;
}
for (int i = 0; i < N; i++) {
q.changePriority(items[i], i);
}
int j = 0;
double pr_last = Double.NEGATIVE_INFINITY;
assertTrue("ascending size", q.size() == N);
while (q.size() > 0) {
assertTrue("ascending extract", j < N);
QueueElement e = q.extractMin();
assertTrue("ascending order", e.getPriority() > pr_last);
pr_last = e.getPriority();
assertEquals("ascending priority", items[j].getPriority(), e.getPriority());
assertEquals("ascending identity", items[j], e);
j++;
}
}
/**
* Insert the specified {@link QueueElement} element into the queue.
*
* @param queueElement the {@link QueueElement} element to add.
* @param ignoreSize if the queue is bound to a maximum size and the maximum size is reached, this
* parameter (if set to <tt>true</tt>) allows to ignore the maximum size and add the element
* to the queue.
* @return <tt>true</tt> if the element has been inserted, <tt>false</tt> if the element was not
* inserted (the queue has reached its maximum size).
* @throws NullPointerException if the specified element is null
*/
boolean offer(QueueElement<E> queueElement, boolean ignoreSize) {
if (queueElement == null) {
throw new NullPointerException("queueElement is NULL");
}
if (queueElement.getPriority() < 0 || queueElement.getPriority() >= priorities) {
throw new IllegalArgumentException("priority out of range: " + queueElement);
}
if (queueElement.inQueue) {
throw new IllegalStateException("queueElement already in a queue: " + queueElement);
}
if (!ignoreSize && currentSize != null && currentSize.get() >= maxSize) {
return false;
}
boolean accepted;
lock.lock();
try {
accepted = queues[queueElement.getPriority()].offer(queueElement);
debug(
"offer([{0}]), to P[{1}] delay[{2}ms] accepted[{3}]",
queueElement.getElement().toString(),
queueElement.getPriority(),
queueElement.getDelay(TimeUnit.MILLISECONDS),
accepted);
if (accepted) {
if (currentSize != null) {
currentSize.incrementAndGet();
}
queueElement.inQueue = true;
}
} finally {
lock.unlock();
}
return accepted;
}
public void testEqualKeys() {
PriorityQueue q = new MinHeap(N);
Item[] items = new Item[20];
int j = 0;
for (int i = 0; i < 5; i++) {
items[j] = new Item(5);
q.insert(items[j]);
j++;
}
for (int i = 0; i < 5; i++) {
items[j] = new Item(3);
q.insert(items[j]);
j++;
}
for (int i = 0; i < 5; i++) {
items[j] = new Item(4);
q.insert(items[j]);
j++;
}
for (int i = 0; i < 5; i++) {
items[j] = new Item(7);
q.insert(items[j]);
j++;
}
assertEquals(20, q.size());
for (int i = 0; i < items.length; i++) {
assertTrue(q.contains(items[i]));
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
assertTrue(q.contains(q.min()));
assertEquals(3.0, e.getPriority());
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
assertTrue(q.contains(q.min()));
assertEquals(4.0, e.getPriority());
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
assertTrue(q.contains(q.min()));
assertEquals(5.0, e.getPriority());
}
for (int i = 0; i < 5; i++) {
QueueElement e = q.extractMin();
if (q.size() > 0) assertTrue(q.contains(q.min()));
assertEquals(7.0, e.getPriority());
}
}
public void testDescending() {
PriorityQueue q = new MinHeap(N);
double p[] = new double[N];
for (int i = 0; i < N; i++) {
p[i] = i;
Item e = new Item(N - i - 1);
q.insert(e);
}
int j = 0;
double pr = Double.NEGATIVE_INFINITY;
assertTrue("descending size", q.size() == N);
while (q.size() > 0) {
assertTrue("descending extract", j < N);
QueueElement e = q.extractMin();
assertTrue("descending order", e.getPriority() > pr);
assertEquals("descending priority", e.getPriority(), p[j++], 1e-5);
pr = e.getPriority();
}
}
/**
* Retrieve, but does not remove, the head of this queue, or returns <tt>null</tt> if this queue
* is empty. Unlike <tt>poll</tt>, if no expired elements are available in the queue, this method
* returns the element that will expire next, if one exists.
*
* @return the head of this queue, or <tt>null</tt> if this queue is empty.
*/
@Override
public QueueElement<E> peek() {
lock.lock();
try {
antiStarvation();
QueueElement<E> e = null;
QueueElement<E>[] seeks = new QueueElement[priorities];
boolean foundElement = false;
for (int i = priorities - 1; i > -1; i--) {
e = queues[i].peek();
debug("peek(): considering [{0}] from P[{1}]", e, i);
seeks[priorities - i - 1] = e;
foundElement |= e != null;
}
if (foundElement) {
e = null;
for (int i = 0; e == null && i < priorities; i++) {
if (seeks[i] != null && seeks[i].getDelay(TimeUnit.MILLISECONDS) > 0) {
debug("peek, ignoring [{0}]", seeks[i]);
} else {
e = seeks[i];
}
}
if (e != null) {
debug("peek(): choosing [{0}]", e);
}
if (e == null) {
int first;
for (first = 0; e == null && first < priorities; first++) {
e = seeks[first];
}
if (e != null) {
debug("peek(): initial choosing [{0}]", e);
}
for (int i = first; i < priorities; i++) {
QueueElement<E> ee = seeks[i];
if (ee != null
&& ee.getDelay(TimeUnit.MILLISECONDS) < e.getDelay(TimeUnit.MILLISECONDS)) {
debug("peek(): choosing [{0}] over [{1}]", ee, e);
e = ee;
}
}
}
}
if (e != null) {
debug("peek(): [{0}], from P[{1}]", e.getElement().toString(), e.getPriority());
} else {
debug("peek(): NULL");
}
return e;
} finally {
lock.unlock();
}
}
public void testChangePriority() {
PriorityQueue q = new MinHeap(N);
Item items[] = new Item[N];
for (int i = 0; i < N; i++) {
Item e = new Item(N - i - 1);
q.insert(e);
items[i] = e;
}
q.changePriority(items[N - 1], -2);
q.changePriority(items[N / 2], -1);
q.changePriority(items[N / 2 + 1], N * 2);
int j = 0;
double pr_last = Double.NEGATIVE_INFINITY;
assertTrue("descending size", q.size() == N);
while (q.size() > 0) {
assertTrue("descending extract", j < N);
QueueElement e = q.extractMin();
assertTrue("descending order", e.getPriority() > pr_last);
pr_last = e.getPriority();
if (j == 0) assertTrue("lowest elt", e.getPriority() == -2);
if (j == 1) assertTrue("second-lowest elt", e.getPriority() == -1);
if (q.size() == 1) assertTrue("penultimate elt", e.getPriority() == N - 1);
if (q.size() == 0) assertTrue("final elt", e.getPriority() == N * 2);
j++;
}
}
