/*- | |
* ============LICENSE_START======================================================= | |
* OSAM | |
* ================================================================================ | |
* Copyright (C) 2018 AT&T | |
* ================================================================================ | |
* Licensed under the Apache License, Version 2.0 (the "License"); | |
* you may not use this file except in compliance with the License. | |
* You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
* ============LICENSE_END========================================================= | |
*/ | |
package org.onap.osam.utils; | |
import java.util.Iterator; | |
import java.util.Spliterator; | |
import java.util.Spliterators; | |
import java.util.function.Consumer; | |
import java.util.function.Predicate; | |
import java.util.stream.Stream; | |
import java.util.stream.StreamSupport; | |
public class Streams { | |
public static <R> Predicate<R> not(Predicate<R> predicate) { | |
return predicate.negate(); | |
} | |
public static <T> Stream<T> fromIterator(final Iterator<T> iterator) { | |
Iterable<T> iterable = () -> iterator; | |
return StreamSupport.<T>stream(iterable.spliterator(), false); | |
} | |
// https://stackoverflow.com/questions/20746429/limit-a-stream-by-a-predicate | |
private static <T> Spliterator<T> takeWhile( | |
Spliterator<T> splitr, Predicate<? super T> predicate) { | |
return new Spliterators.AbstractSpliterator<T>(splitr.estimateSize(), 0) { | |
boolean stillGoing = true; | |
@Override public boolean tryAdvance(Consumer<? super T> consumer) { | |
if (stillGoing) { | |
boolean hadNext = splitr.tryAdvance(elem -> { | |
if (predicate.test(elem)) { | |
consumer.accept(elem); | |
} else { | |
stillGoing = false; | |
} | |
}); | |
return hadNext && stillGoing; | |
} | |
return false; | |
} | |
}; | |
} | |
public static <T> Stream<T> takeWhile(Stream<T> stream, Predicate<? super T> predicate) { | |
return StreamSupport.stream(takeWhile(stream.spliterator(), predicate), false); | |
} | |
} |