Java Utililty Methods Stream Operation

List of utility methods to do Stream Operation

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Description

The list of methods to do Stream Operation are organized into topic(s).

Method

booleancontainsOnly(Stream stream, long size)
Helper which lazily checks if a Stream contains the number specified WARNING: This consumes the stream rendering it unusable afterwards 
long count = 0L;
Iterator it = stream.iterator();
while (it.hasNext()) {
    it.next();
    if (++count > size)
        return false;
return size == count;
...
StreamcreateStream(final Iterator iterator)
Creates a stream based on the provided iterator. 
requireNonNull(iterator, "Iterator must not be null");
return StreamSupport.stream(Spliterators.spliterator(iterator, 0L, 0), false);
booleanendsWith(Stream stream, Iterable iterable)
ends With 
Iterator<T> it = iterable.iterator();
List<T> compare1 = new ArrayList<>();
while (it.hasNext()) {
    compare1.add(it.next());
LinkedList<T> list = new LinkedList<>();
stream.forEach(v -> {
    list.add(v);
...
StreamenumerationAsStream(Enumeration e)
enumeration As Stream 
return StreamSupport.stream(Spliterators.spliteratorUnknownSize(new Iterator<T>() {
    public T next() {
        return e.nextElement();
    public boolean hasNext() {
        return e.hasMoreElements();
}, Spliterator.ORDERED), false);
...
booleanequals(Stream first, Stream second)
equals 
Iterator<?> firstIterator = first.iterator();
Iterator<?> secondIterator = second.iterator();
while (firstIterator.hasNext() && secondIterator.hasNext()) {
    if (!Objects.equals(firstIterator.next(), secondIterator.next())) {
        return false;
return !firstIterator.hasNext() && !secondIterator.hasNext();
...
LongStreamfactorStream(long number)
factor Stream 
return LongStream.rangeClosed(2, (long) Math.sqrt(number)).filter(f -> number % f == 0)
        .flatMap(f -> LongStream.of(f, number / f)).sorted();
StreamfilterInstances(Stream stream, Class clazz)
filter Instances 
return stream.filter(clazz::isInstance);
StreamfilterType(Stream stream, Class type)
filter Type 
return (Stream<Sub>) stream.filter(it -> type.isInstance(it));
OptionalfindLast(Stream s)
find Last 
return Optional.ofNullable(s.reduce(null, (p, c) -> c));
OptionalfindLastOf(Stream stream)
Based on http://stackoverflow.com/questions/27547519/most-efficient-way-to-get-the-last-element-of-a-stream 
Spliterator<T> split = stream.spliterator();
if (split.hasCharacteristics(Spliterator.SIZED | Spliterator.SUBSIZED)) {
    while (true) {
        Spliterator<T> part = split.trySplit();
        if (part == null) {
            break;
        if (split.getExactSizeIfKnown() == 0) {
...