/*
* Copyright 2016 Google Inc.
*
* 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.
*/
package java.util.stream;
import static javaemul.internal.InternalPreconditions.checkState;
import java.util.Arrays;
import java.util.Comparator;
import java.util.LongSummaryStatistics;
import java.util.OptionalDouble;
import java.util.OptionalLong;
import java.util.PrimitiveIterator;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.Spliterators.AbstractLongSpliterator;
import java.util.function.BiConsumer;
import java.util.function.LongBinaryOperator;
import java.util.function.LongConsumer;
import java.util.function.LongFunction;
import java.util.function.LongPredicate;
import java.util.function.LongSupplier;
import java.util.function.LongToDoubleFunction;
import java.util.function.LongToIntFunction;
import java.util.function.LongUnaryOperator;
import java.util.function.ObjLongConsumer;
import java.util.function.Supplier;
/**
* See <a href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/LongStream.html">
* the official Java API doc</a> for details.
*/
public interface LongStream extends BaseStream<Long, LongStream> {
/**
* See <a
* href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/LongStream.Builder.html">the
* official Java API doc</a> for details.
*/
interface Builder extends LongConsumer {
@Override
void accept(long t);
default LongStream.Builder add(long t) {
accept(t);
return this;
}
LongStream build();
}
static Builder builder() {
return new Builder() {
private long[] items = new long[0];
@Override
public void accept(long t) {
checkState(items != null, "Builder already built");
items[items.length] = t;
}
@Override
public LongStream build() {
checkState(items != null, "Builder already built");
LongStream stream = Arrays.stream(items);
items = null;
return stream;
}
};
}
static LongStream concat(LongStream a, LongStream b) {
// This is nearly the same as flatMap, but inlined, wrapped around a single spliterator of
// these two objects, and without close() called as the stream progresses. Instead, close is
// invoked as part of the resulting stream's own onClose, so that either can fail without
// affecting the other, and correctly collecting suppressed exceptions.
// TODO replace this flatMap-ish spliterator with one that directly combines the two root
// streams
Spliterator<? extends LongStream> spliteratorOfStreams = Arrays.asList(a, b).spliterator();
AbstractLongSpliterator spliterator =
new Spliterators.AbstractLongSpliterator(Long.MAX_VALUE, 0) {
Spliterator.OfLong next;
@Override
public boolean tryAdvance(LongConsumer action) {
// look for a new spliterator
while (advanceToNextSpliterator()) {
// if we have one, try to read and use it
if (next.tryAdvance(action)) {
return true;
} else {
// failed, null it out so we can find another
next = null;
}
}
return false;
}
private boolean advanceToNextSpliterator() {
while (next == null) {
if (!spliteratorOfStreams.tryAdvance(
n -> {
if (n != null) {
next = n.spliterator();
}
})) {
return false;
}
}
return true;
}
};
LongStream result = new LongStreamImpl(null, spliterator);
return result.onClose(a::close).onClose(b::close);
}
static LongStream empty() {
return new LongStreamImpl.Empty(null);
}
static LongStream generate(LongSupplier s) {
AbstractLongSpliterator spltierator =
new Spliterators.AbstractLongSpliterator(
Long.MAX_VALUE, Spliterator.IMMUTABLE | Spliterator.ORDERED) {
@Override
public boolean tryAdvance(LongConsumer action) {
action.accept(s.getAsLong());
return true;
}
};
return StreamSupport.longStream(spltierator, false);
}
static LongStream iterate(long seed, LongUnaryOperator f) {
AbstractLongSpliterator spliterator =
new Spliterators.AbstractLongSpliterator(
Long.MAX_VALUE, Spliterator.IMMUTABLE | Spliterator.ORDERED) {
private long next = seed;
@Override
public boolean tryAdvance(LongConsumer action) {
action.accept(next);
next = f.applyAsLong(next);
return true;
}
};
return StreamSupport.longStream(spliterator, false);
}
static LongStream of(long... values) {
return Arrays.stream(values);
}
static LongStream of(long t) {
// TODO consider a splittable that returns only a single value
return of(new long[] {t});
}
static LongStream range(long startInclusive, long endExclusive) {
if (startInclusive >= endExclusive) {
return empty();
}
return rangeClosed(startInclusive, endExclusive - 1);
}
static LongStream rangeClosed(long startInclusive, long endInclusive) {
if (startInclusive > endInclusive) {
return empty();
}
long count = endInclusive - startInclusive + 1;
AbstractLongSpliterator spliterator =
new Spliterators.AbstractLongSpliterator(
count,
Spliterator.IMMUTABLE
| Spliterator.SIZED
| Spliterator.SUBSIZED
| Spliterator.ORDERED
| Spliterator.SORTED
| Spliterator.DISTINCT) {
private long next = startInclusive;
@Override
public Comparator<? super Long> getComparator() {
return null;
}
@Override
public boolean tryAdvance(LongConsumer action) {
if (next <= endInclusive) {
action.accept(next++);
return true;
}
return false;
}
};
return StreamSupport.longStream(spliterator, false);
}
boolean allMatch(LongPredicate predicate);
boolean anyMatch(LongPredicate predicate);
DoubleStream asDoubleStream();
OptionalDouble average();
Stream<Long> boxed();
<R> R collect(Supplier<R> supplier, ObjLongConsumer<R> accumulator, BiConsumer<R, R> combiner);
long count();
LongStream distinct();
LongStream filter(LongPredicate predicate);
OptionalLong findAny();
OptionalLong findFirst();
LongStream flatMap(LongFunction<? extends LongStream> mapper);
void forEach(LongConsumer action);
void forEachOrdered(LongConsumer action);
@Override
PrimitiveIterator.OfLong iterator();
LongStream limit(long maxSize);
LongStream map(LongUnaryOperator mapper);
DoubleStream mapToDouble(LongToDoubleFunction mapper);
IntStream mapToInt(LongToIntFunction mapper);
<U> Stream<U> mapToObj(LongFunction<? extends U> mapper);
OptionalLong max();
OptionalLong min();
boolean noneMatch(LongPredicate predicate);
@Override
LongStream parallel();
LongStream peek(LongConsumer action);
OptionalLong reduce(LongBinaryOperator op);
long reduce(long identity, LongBinaryOperator op);
@Override
LongStream sequential();
LongStream skip(long n);
LongStream sorted();
@Override
Spliterator.OfLong spliterator();
long sum();
LongSummaryStatistics summaryStatistics();
long[] toArray();
}