There’s no such function in the API as it supports both sequential and parallel processing and it’s really hard to provide an efficient parallel processing for sliding window function for arbitrary stream source (even efficient pairs parallel processing is quite hard, I implemented it, so I know). However if your source is the List with … Read more
In java 11 there is a new method Predicate::not. So you can filter out empty string : list.stream() .filter(Objects::nonNull) .filter(Predicate.not(String::isEmpty))
We all know or be told that creating a new thread is a heavy operation. But it seems okay to me after ran a few tests. For example: Here is the memory usage by run below simple test with 10_000 thread. It took about 2 or 3 seconds on my laptop and jvm usage is … Read more
If you want to implement equals and hashCode, the place to do it is inside the class Parent. Within that class add the methods like @Override public int hashCode() { return Objects.hash(getAttrib1(), getAttrib2(), getAttrib3(), // … getAttrib19(), getAttrib20()); } @Override public boolean equals(Object obj) { if(this==obj) return true; if(!(obj instanceof Parent)) return false; Parent p=(Parent) … Read more
The API documentation makes no such guarantee “that subsequent operations no longer operate on the backing collection”, hence, you should never rely on such a behavior of a particular implementation. Your example happens to do the desired thing by accident; there’s not even a guarantee that the List created by collect(Collectors.toList()) supports the remove operation. … Read more
There’s a subtle difference, because anyMatch family uses a predicate, while findAny family does not. Technically findAny() looks like anyMatch(x -> true) and anyMatch(pred) looks like filter(pred).findAny(). So here we have another issue. Consider we have a simple infinite stream: Stream<Integer> s = Stream.generate(() -> 1); So it’s true that applying findAny() to such stream … Read more
Stream.of(array).parallel() or Arrays.stream(array).parallel()
The mapToDouble call is not useless: it performs an implicit unboxing. Actually it’s the same as double totalevent = myList.stream().mapToDouble(f -> f.doubleValue()).sum(); Or double totalevent = myList.stream().mapToDouble(Double::doubleValue).sum(); Alternatively you can use summingDouble collector, but it’s not a big difference: double totalevent = myList.stream().collect(summingDouble(f -> f)); In my StreamEx library you can construct a DoubleStream directly … Read more
static <T> Stream<T> iteratorToFiniteStream(final Iterator<T> iterator) { return StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, 0), false); } static <T> Stream<T> iteratorToInfiniteStream(final Iterator<T> iterator) { return Stream.generate(iterator::next); }
ArrayNode implements Iterable. Iterable has a spliterator() method. You can create a sequential Stream from a Spliterator using ArrayNode arrayNode = (ArrayNode) json.get(“xyz”); StreamSupport.stream(arrayNode.spliterator(), false)