@Override
public void forEachRemaining(Consumer<? super R> action) {
while (left != null) {
accept(handleLeft(), action);
}
if (cur == none()) {
if (!source.tryAdvance(this)) {
accept(pushRight(none(), none()), action);
return;
}
}
acc = mapper.apply(cur);
source.forEachRemaining(
next -> {
if (!this.mergeable.test(cur, next)) {
action.accept(acc);
acc = mapper.apply(next);
} else {
acc = accumulator.apply(acc, next);
}
cur = next;
});
if (accept(pushRight(acc, cur), action)) {
if (right != null) {
action.accept(right.acc);
right = null;
}
}
}
@Override
public int characteristics() {
int c = NONNULL;
c |= spliterator.hasCharacteristics(ORDERED) ? ORDERED : 0;
c |= spliterator.hasCharacteristics(SIZED) ? SIZED : 0;
return c;
}
@Override
public boolean tryAdvance(Consumer<? super R> action) {
if (left != null) {
if (accept(handleLeft(), action)) {
return true;
}
}
if (cur == none()) { // start
if (!source.tryAdvance(this)) {
return accept(pushRight(none(), none()), action);
}
}
T first = cur;
R acc = mapper.apply(cur);
T last = first;
while (source.tryAdvance(this)) {
if (!this.mergeable.test(last, cur)) {
action.accept(acc);
return true;
}
last = cur;
acc = this.accumulator.apply(acc, last);
}
return accept(pushRight(acc, last), action);
}
@Test
public void splitsEventsBackward() {
final String stream = generateStreamName();
List<EventData> events = newTestEvents(40);
eventstore.appendToStream(stream, ExpectedVersion.NO_STREAM, events).join();
Spliterator<ResolvedEvent> spliterator =
new StreamEventsSpliterator(
StreamPosition.END, i -> eventstore.readStreamEventsBackward(stream, i, 8, false));
List<ResolvedEvent> result = new ArrayList<>();
range(0, 5)
.forEach(
i -> {
Spliterator<ResolvedEvent> s = spliterator.trySplit();
assertNotNull(s);
s.forEachRemaining(result::add);
});
assertEquals(40, result.size());
assertNull(spliterator.trySplit());
spliterator.forEachRemaining(e -> fail("Should be no more elements remaining"));
assertFalse(spliterator.tryAdvance(result::add));
assertEquals(40, result.size());
assertThat(recordedEventsFrom(result), containsInOrder(reverse(events)));
}
@Test
public void failsWhenActionIsNull() {
Spliterator<ResolvedEvent> spliterator =
new StreamEventsSpliterator(
StreamPosition.START, i -> eventstore.readStreamEventsForward("foo", i, 1, false));
try {
spliterator.tryAdvance(null);
fail("should fail with 'NullPointerException'");
} catch (Exception e) {
assertThat(e, instanceOf(NullPointerException.class));
}
try {
spliterator.forEachRemaining(null);
fail("should fail with 'NullPointerException'");
} catch (Exception e) {
assertThat(e, instanceOf(NullPointerException.class));
}
}
@Override
public Spliterator<R> trySplit() {
Spliterator<T> prefix = source.trySplit();
if (prefix == null) return null;
Connector<T, R> newBox = new Connector<>(null, none(), this);
synchronized (root) {
CollapseSpliterator<T, R> result = new CollapseSpliterator<>(root, prefix, left, newBox);
this.left = newBox;
return result;
}
}
@Test
public void splitsAndIteratesEventsBackward() {
final String stream = generateStreamName();
List<EventData> events = newTestEvents(40);
eventstore.appendToStream(stream, ExpectedVersion.NO_STREAM, events).join();
Spliterator<ResolvedEvent> spliterator =
new StreamEventsSpliterator(
StreamPosition.END, i -> eventstore.readStreamEventsBackward(stream, i, 8, false));
List<ResolvedEvent> result = new ArrayList<>();
Spliterator<ResolvedEvent> s1;
s1 = spliterator.trySplit();
assertNotNull(s1);
s1.forEachRemaining(result::add);
spliterator.forEachRemaining(result::add);
assertNull(spliterator.trySplit());
assertEquals(40, result.size());
assertThat(recordedEventsFrom(result), containsInOrder(reverse(events)));
}
/**
* Overrides AbstractTask version to include checks for early exits while splitting or computing.
*/
@Override
public void compute() {
Spliterator<P_IN> rs = spliterator, ls;
long sizeEstimate = rs.estimateSize();
long sizeThreshold = getTargetSize(sizeEstimate);
boolean forkRight = false;
@SuppressWarnings("unchecked")
K task = (K) this;
AtomicReference<R> sr = sharedResult;
R result;
while ((result = sr.get()) == null) {
if (task.taskCanceled()) {
result = task.getEmptyResult();
break;
}
if (sizeEstimate <= sizeThreshold || (ls = rs.trySplit()) == null) {
result = task.doLeaf();
break;
}
K leftChild, rightChild, taskToFork;
task.leftChild = leftChild = task.makeChild(ls);
task.rightChild = rightChild = task.makeChild(rs);
task.setPendingCount(1);
if (forkRight) {
forkRight = false;
rs = ls;
task = leftChild;
taskToFork = rightChild;
} else {
forkRight = true;
task = rightChild;
taskToFork = leftChild;
}
taskToFork.fork();
sizeEstimate = rs.estimateSize();
}
task.setLocalResult(result);
task.tryComplete();
}
@Test
public void iteratesAllRemainingEventsForwardWithoutTryAdvanceCall() {
final String stream = generateStreamName();
List<EventData> events = newTestEvents(19);
eventstore.appendToStream(stream, ExpectedVersion.NO_STREAM, events).join();
Spliterator<ResolvedEvent> spliterator =
new StreamEventsSpliterator(
StreamPosition.START, i -> eventstore.readStreamEventsForward(stream, i, 17, false));
List<ResolvedEvent> result = new ArrayList<>();
spliterator.forEachRemaining(result::add);
assertFalse(spliterator.tryAdvance(result::add));
spliterator.forEachRemaining(e -> fail("Should be no more elements remaining"));
assertNull(spliterator.trySplit());
assertEquals(19, result.size());
assertThat(recordedEventsFrom(result), containsInOrder(events));
}
@Override
public Void call() throws Exception {
String baseUrl = PropertyHandler.getInstance().getValue("baseUrl");
String urlPageSuffix = PropertyHandler.getInstance().getValue("urlPageSuffix");
String numberOfPages = PropertyHandler.getInstance().getValue("numberOfPages");
String tagToParse = PropertyHandler.getInstance().getValue("tagToParse");
assert (numberOfPages.matches("^-?\\d+$")); // make sure someone supplied only numbers
Elements headlines = null;
int goal = Integer.parseInt(numberOfPages);
try {
for (int i = 0; i < goal; i++) {
String url = baseUrl + urlPageSuffix + i;
headlines = fetchContent(url, tagToParse);
Spliterator<Element> elementSpliterator = headlines.spliterator().trySplit();
elementSpliterator.forEachRemaining(
headline -> {
try {
if (!headline.text().toLowerCase().contains("permalink")) {
logger.info("Produced: " + headline);
queue.put(headline);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
});
Thread.sleep(1000);
}
this.queue.continueProducing = Boolean.FALSE;
System.out.println("Producer finished its job; terminating.");
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
private R handleLeft() {
synchronized (root) {
Connector<T, R> l = left;
if (l == null) {
return none();
}
if (l.left == NONE && l.right == NONE && l.acc != NONE) {
return l.drain();
}
}
if (source.tryAdvance(this)) {
T first = this.cur;
T last = first;
R acc = this.mapper.apply(first);
while (source.tryAdvance(this)) {
if (!this.mergeable.test(last, cur)) return pushLeft(first, acc);
last = cur;
acc = this.accumulator.apply(acc, last);
}
cur = none();
return connectOne(first, acc, last);
}
return connectEmpty();
}
@Test
public void iteratesAndSplitsEventsForward() {
final String stream = generateStreamName();
List<EventData> events = newTestEvents(17);
eventstore.appendToStream(stream, ExpectedVersion.NO_STREAM, events).join();
Spliterator<ResolvedEvent> spliterator =
new StreamEventsSpliterator(
StreamPosition.START, i -> eventstore.readStreamEventsForward(stream, i, 5, false));
List<ResolvedEvent> result = new ArrayList<>();
Spliterator<ResolvedEvent> s1, s2, s3;
assertTrue(spliterator.tryAdvance(result::add));
s1 = spliterator.trySplit();
assertNotNull(s1);
assertTrue(s1.tryAdvance(result::add));
s2 = s1.trySplit();
assertNotNull(s2);
assertTrue(s2.tryAdvance(result::add));
s2.forEachRemaining(result::add);
assertTrue(s1.tryAdvance(result::add));
s1.forEachRemaining(result::add);
assertTrue(spliterator.tryAdvance(result::add));
s3 = spliterator.trySplit();
assertNotNull(s3);
assertTrue(s3.tryAdvance(result::add));
s3.forEachRemaining(result::add);
assertTrue(spliterator.tryAdvance(result::add));
spliterator.forEachRemaining(result::add);
assertNull(spliterator.trySplit());
assertEquals(17, result.size());
assertThat(recordedEventsFrom(result), containsInOrder(events));
}
@Override
public int characteristics() {
return source.characteristics() & (CONCURRENT | IMMUTABLE | ORDERED);
}
@Override
public long estimateSize() {
return source.estimateSize();
}