com.google.common.collect.CollectSpliterators Maven / Gradle / Ivy
Go to download
This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including
all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and
Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright (C) 2015 The Guava Authors
*
* 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 com.google.common.collect;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.GwtCompatible;
import java.util.Comparator;
import java.util.Spliterator;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.IntConsumer;
import java.util.function.IntFunction;
import java.util.function.Predicate;
import java.util.stream.IntStream;
import org.checkerframework.checker.nullness.compatqual.NullableDecl;
/** Spliterator utilities for {@code common.collect} internals. */
@GwtCompatible
final class CollectSpliterators {
private CollectSpliterators() {}
static Spliterator indexed(int size, int extraCharacteristics, IntFunction function) {
return indexed(size, extraCharacteristics, function, null);
}
static Spliterator indexed(
int size,
int extraCharacteristics,
IntFunction function,
Comparator comparator) {
if (comparator != null) {
checkArgument((extraCharacteristics & (Spliterator.SORTED)) != 0);
}
class WithCharacteristics implements Spliterator {
private final Spliterator.OfInt delegate;
WithCharacteristics(Spliterator.OfInt delegate) {
this.delegate = delegate;
}
@Override
public boolean tryAdvance(Consumer action) {
return delegate.tryAdvance((IntConsumer) i -> action.accept(function.apply(i)));
}
@Override
public void forEachRemaining(Consumer action) {
delegate.forEachRemaining((IntConsumer) i -> action.accept(function.apply(i)));
}
@Override
@NullableDecl
public Spliterator trySplit() {
Spliterator.OfInt split = delegate.trySplit();
return (split == null) ? null : new WithCharacteristics(split);
}
@Override
public long estimateSize() {
return delegate.estimateSize();
}
@Override
public int characteristics() {
return Spliterator.ORDERED
| Spliterator.SIZED
| Spliterator.SUBSIZED
| extraCharacteristics;
}
@Override
public Comparator getComparator() {
if (hasCharacteristics(Spliterator.SORTED)) {
return comparator;
} else {
throw new IllegalStateException();
}
}
}
return new WithCharacteristics(IntStream.range(0, size).spliterator());
}
/**
* Returns a {@code Spliterator} over the elements of {@code fromSpliterator} mapped by {@code
* function}.
*/
static Spliterator map(
Spliterator fromSpliterator, Function function) {
checkNotNull(fromSpliterator);
checkNotNull(function);
return new Spliterator() {
@Override
public boolean tryAdvance(Consumer action) {
return fromSpliterator.tryAdvance(
fromElement -> action.accept(function.apply(fromElement)));
}
@Override
public void forEachRemaining(Consumer action) {
fromSpliterator.forEachRemaining(fromElement -> action.accept(function.apply(fromElement)));
}
@Override
public Spliterator trySplit() {
Spliterator fromSplit = fromSpliterator.trySplit();
return (fromSplit != null) ? map(fromSplit, function) : null;
}
@Override
public long estimateSize() {
return fromSpliterator.estimateSize();
}
@Override
public int characteristics() {
return fromSpliterator.characteristics()
& ~(Spliterator.DISTINCT | Spliterator.NONNULL | Spliterator.SORTED);
}
};
}
/** Returns a {@code Spliterator} filtered by the specified predicate. */
static Spliterator filter(Spliterator fromSpliterator, Predicate predicate) {
checkNotNull(fromSpliterator);
checkNotNull(predicate);
class Splitr implements Spliterator, Consumer {
T holder = null;
@Override
public void accept(T t) {
this.holder = t;
}
@Override
public boolean tryAdvance(Consumer action) {
while (fromSpliterator.tryAdvance(this)) {
try {
if (predicate.test(holder)) {
action.accept(holder);
return true;
}
} finally {
holder = null;
}
}
return false;
}
@Override
public Spliterator trySplit() {
Spliterator fromSplit = fromSpliterator.trySplit();
return (fromSplit == null) ? null : filter(fromSplit, predicate);
}
@Override
public long estimateSize() {
return fromSpliterator.estimateSize() / 2;
}
@Override
public Comparator getComparator() {
return fromSpliterator.getComparator();
}
@Override
public int characteristics() {
return fromSpliterator.characteristics()
& (Spliterator.DISTINCT
| Spliterator.NONNULL
| Spliterator.ORDERED
| Spliterator.SORTED);
}
}
return new Splitr();
}
/**
* Returns a {@code Spliterator} that iterates over the elements of the spliterators generated by
* applying {@code function} to the elements of {@code fromSpliterator}.
*/
static Spliterator flatMap(
Spliterator fromSpliterator,
Function> function,
int topCharacteristics,
long topSize) {
checkArgument(
(topCharacteristics & Spliterator.SUBSIZED) == 0,
"flatMap does not support SUBSIZED characteristic");
checkArgument(
(topCharacteristics & Spliterator.SORTED) == 0,
"flatMap does not support SORTED characteristic");
checkNotNull(fromSpliterator);
checkNotNull(function);
class FlatMapSpliterator implements Spliterator {
@NullableDecl Spliterator prefix;
final Spliterator from;
int characteristics;
long estimatedSize;
FlatMapSpliterator(
Spliterator prefix, Spliterator from, int characteristics, long estimatedSize) {
this.prefix = prefix;
this.from = from;
this.characteristics = characteristics;
this.estimatedSize = estimatedSize;
}
@Override
public boolean tryAdvance(Consumer action) {
while (true) {
if (prefix != null && prefix.tryAdvance(action)) {
if (estimatedSize != Long.MAX_VALUE) {
estimatedSize--;
}
return true;
} else {
prefix = null;
}
if (!from.tryAdvance(fromElement -> prefix = function.apply(fromElement))) {
return false;
}
}
}
@Override
public void forEachRemaining(Consumer action) {
if (prefix != null) {
prefix.forEachRemaining(action);
prefix = null;
}
from.forEachRemaining(fromElement -> function.apply(fromElement).forEachRemaining(action));
estimatedSize = 0;
}
@Override
public Spliterator trySplit() {
Spliterator fromSplit = from.trySplit();
if (fromSplit != null) {
int splitCharacteristics = characteristics & ~Spliterator.SIZED;
long estSplitSize = estimateSize();
if (estSplitSize < Long.MAX_VALUE) {
estSplitSize /= 2;
this.estimatedSize -= estSplitSize;
this.characteristics = splitCharacteristics;
}
Spliterator result =
new FlatMapSpliterator(this.prefix, fromSplit, splitCharacteristics, estSplitSize);
this.prefix = null;
return result;
} else if (prefix != null) {
Spliterator result = prefix;
this.prefix = null;
return result;
} else {
return null;
}
}
@Override
public long estimateSize() {
if (prefix != null) {
estimatedSize = Math.max(estimatedSize, prefix.estimateSize());
}
return Math.max(estimatedSize, 0);
}
@Override
public int characteristics() {
return characteristics;
}
}
return new FlatMapSpliterator(null, fromSpliterator, topCharacteristics, topSize);
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy