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A general programming library in Java
/*
* Copyright (C) 2016 HaiYang Li
*
* 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.landawn.abacus.util.stream;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Deque;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Set;
import com.landawn.abacus.util.ByteIterator;
import com.landawn.abacus.util.CharIterator;
import com.landawn.abacus.util.DoubleIterator;
import com.landawn.abacus.util.FloatIterator;
import com.landawn.abacus.util.Indexed;
import com.landawn.abacus.util.IntIterator;
import com.landawn.abacus.util.LongIterator;
import com.landawn.abacus.util.LongMultiset;
import com.landawn.abacus.util.Multimap;
import com.landawn.abacus.util.Multiset;
import com.landawn.abacus.util.N;
import com.landawn.abacus.util.NullabLe;
import com.landawn.abacus.util.ShortIterator;
import com.landawn.abacus.util.function.BiConsumer;
import com.landawn.abacus.util.function.BiFunction;
import com.landawn.abacus.util.function.BiPredicate;
import com.landawn.abacus.util.function.BinaryOperator;
import com.landawn.abacus.util.function.Consumer;
import com.landawn.abacus.util.function.Function;
import com.landawn.abacus.util.function.IntFunction;
import com.landawn.abacus.util.function.Predicate;
import com.landawn.abacus.util.function.Supplier;
import com.landawn.abacus.util.function.ToByteFunction;
import com.landawn.abacus.util.function.ToCharFunction;
import com.landawn.abacus.util.function.ToDoubleFunction;
import com.landawn.abacus.util.function.ToFloatFunction;
import com.landawn.abacus.util.function.ToIntFunction;
import com.landawn.abacus.util.function.ToLongFunction;
import com.landawn.abacus.util.function.ToShortFunction;
import com.landawn.abacus.util.function.TriConsumer;
import com.landawn.abacus.util.function.TriFunction;
import com.landawn.abacus.util.stream.ExIterator.QueuedIterator;
/**
* This class is a sequential, stateful and immutable stream implementation.
*
* @param
* @since 0.8
*
* @author Haiyang Li
*/
class IteratorStream extends AbstractStream {
final ExIterator elements;
NullabLe head;
Stream tail;
Stream head2;
NullabLe tail2;
IteratorStream(final Iterator values) {
this(values, null);
}
IteratorStream(final Iterator values, final Collection closeHandlers) {
this(values, closeHandlers, false, null);
}
IteratorStream(final Iterator values, final Collection closeHandlers, final boolean sorted, final Comparator comparator) {
super(closeHandlers, sorted, comparator);
N.requireNonNull(values);
ExIterator tmp = null;
if (values instanceof ExIterator) {
tmp = (ExIterator) values;
} else if (values instanceof SkippableIterator) {
tmp = new ExIterator() {
@Override
public boolean hasNext() {
return values.hasNext();
}
@Override
public T next() {
return values.next();
}
@Override
public void skip(long n) {
((SkippableIterator) values).skip(n);
}
@Override
public long count() {
return ((SkippableIterator) values).count();
}
};
} else {
tmp = new ExIterator() {
@Override
public boolean hasNext() {
return values.hasNext();
}
@Override
public T next() {
return values.next();
}
};
}
this.elements = tmp;
}
IteratorStream(final Stream stream, final Set closeHandlers, final boolean sorted, final Comparator comparator) {
this(stream.iterator(), mergeCloseHandlers(stream, closeHandlers), sorted, comparator);
}
@Override
public Stream filter(final Predicate predicate) {
return new IteratorStream<>(new ExIterator() {
private boolean hasNext = false;
private T next = null;
@Override
public boolean hasNext() {
if (hasNext == false) {
while (elements.hasNext()) {
next = elements.next();
if (predicate.test(next)) {
hasNext = true;
break;
}
}
}
return hasNext;
}
@Override
public T next() {
if (hasNext == false && hasNext() == false) {
throw new NoSuchElementException();
}
hasNext = false;
return next;
}
}, closeHandlers, sorted, cmp);
}
@Override
public Stream takeWhile(final Predicate predicate) {
return new IteratorStream<>(new ExIterator() {
private boolean hasMore = true;
private boolean hasNext = false;
private T next = null;
@Override
public boolean hasNext() {
if (hasNext == false && hasMore && elements.hasNext()) {
next = elements.next();
if (predicate.test(next)) {
hasNext = true;
} else {
hasMore = false;
}
}
return hasNext;
}
@Override
public T next() {
if (hasNext == false && hasNext() == false) {
throw new NoSuchElementException();
}
hasNext = false;
return next;
}
}, closeHandlers, sorted, cmp);
}
@Override
public Stream dropWhile(final Predicate predicate) {
return new IteratorStream<>(new ExIterator() {
private boolean hasNext = false;
private T next = null;
private boolean dropped = false;
@Override
public boolean hasNext() {
if (hasNext == false) {
if (dropped == false) {
while (elements.hasNext()) {
next = elements.next();
if (predicate.test(next) == false) {
hasNext = true;
break;
}
}
dropped = true;
} else if (elements.hasNext()) {
next = elements.next();
hasNext = true;
}
}
return hasNext;
}
@Override
public T next() {
if (hasNext == false && hasNext() == false) {
throw new NoSuchElementException();
}
hasNext = false;
return next;
}
}, closeHandlers, sorted, cmp);
}
@Override
public Stream map(final Function mapper) {
return new IteratorStream<>(new ExIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public R next() {
return mapper.apply(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
public Stream biMap(final BiFunction mapper, final boolean ignoreNotPaired) {
return new IteratorStream<>(new ExIterator() {
private T pre = (T) NONE;
@Override
public boolean hasNext() {
if (ignoreNotPaired && pre == NONE) {
if (elements.hasNext()) {
pre = elements.next();
} else {
return false;
}
}
return elements.hasNext();
}
@Override
public R next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
if (ignoreNotPaired) {
final R res = mapper.apply(pre, elements.next());
pre = (T) NONE;
return res;
} else {
return mapper.apply(elements.next(), elements.hasNext() ? elements.next() : null);
}
}
}, closeHandlers);
}
@Override
public Stream triMap(final TriFunction mapper, final boolean ignoreNotPaired) {
return new IteratorStream<>(new ExIterator() {
private T prepre = (T) NONE;
private T pre = (T) NONE;
@Override
public boolean hasNext() {
if (ignoreNotPaired && pre == NONE) {
if (elements.hasNext()) {
prepre = elements.next();
if (elements.hasNext()) {
pre = elements.next();
} else {
return false;
}
} else {
return false;
}
}
return elements.hasNext();
}
@Override
public R next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
if (ignoreNotPaired) {
final R res = mapper.apply(prepre, pre, elements.next());
prepre = (T) NONE;
pre = (T) NONE;
return res;
} else {
return mapper.apply(elements.next(), elements.hasNext() ? elements.next() : null, elements.hasNext() ? elements.next() : null);
}
}
}, closeHandlers);
}
@Override
public Stream mapFirst(final Function mapperForFirst) {
N.requireNonNull(mapperForFirst);
if (elements.hasNext()) {
T first = elements.next();
return prepend(Stream.of(first).map(mapperForFirst));
} else {
return this;
}
}
@Override
public Stream mapFirstOrElse(final Function mapperForFirst, final Function mapperForElse) {
N.requireNonNull(mapperForFirst);
N.requireNonNull(mapperForElse);
if (elements.hasNext()) {
final Function mapperForFirst2 = (Function) mapperForFirst;
final Function mapperForElse2 = (Function) mapperForElse;
final T first = elements.next();
return map(mapperForElse2).prepend(Stream.of(first).map(mapperForFirst2));
} else {
return (Stream) this;
}
}
@Override
public Stream mapLast(final Function mapperForLast) {
N.requireNonNull(mapperForLast);
return new IteratorStream<>(new ExIterator() {
private T last = (T) Stream.NONE;
@Override
public boolean hasNext() {
return last != Stream.NONE || elements.hasNext();
}
@Override
public T next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
if (last == Stream.NONE) {
last = elements.next();
}
final T next = last;
if (elements.hasNext()) {
last = elements.next();
return next;
} else {
last = (T) Stream.NONE;
return mapperForLast.apply(next);
}
}
}, closeHandlers);
}
@Override
public Stream mapLastOrElse(final Function mapperForLast, final Function mapperForElse) {
N.requireNonNull(mapperForLast);
N.requireNonNull(mapperForElse);
return new IteratorStream<>(new ExIterator() {
private T last = (T) Stream.NONE;
@Override
public boolean hasNext() {
return last != Stream.NONE || elements.hasNext();
}
@Override
public R next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
if (last == Stream.NONE) {
last = elements.next();
}
final T next = last;
if (elements.hasNext()) {
last = elements.next();
return mapperForElse.apply(next);
} else {
last = (T) Stream.NONE;
return mapperForLast.apply(next);
}
}
}, closeHandlers);
}
@Override
public CharStream mapToChar(final ToCharFunction mapper) {
return new IteratorCharStream(new ExCharIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public char nextChar() {
return mapper.applyAsChar(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
public ByteStream mapToByte(final ToByteFunction mapper) {
return new IteratorByteStream(new ExByteIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public byte nextByte() {
return mapper.applyAsByte(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
public ShortStream mapToShort(final ToShortFunction mapper) {
return new IteratorShortStream(new ExShortIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public short nextShort() {
return mapper.applyAsShort(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
public IntStream mapToInt(final ToIntFunction mapper) {
return new IteratorIntStream(new ExIntIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public int nextInt() {
return mapper.applyAsInt(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
public LongStream mapToLong(final ToLongFunction mapper) {
return new IteratorLongStream(new ExLongIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public long nextLong() {
return mapper.applyAsLong(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
public FloatStream mapToFloat(final ToFloatFunction mapper) {
return new IteratorFloatStream(new ExFloatIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public float nextFloat() {
return mapper.applyAsFloat(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
public DoubleStream mapToDouble(final ToDoubleFunction mapper) {
return new IteratorDoubleStream(new ExDoubleIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public double nextDouble() {
return mapper.applyAsDouble(elements.next());
}
@Override
public long count() {
return elements.count();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers);
}
@Override
Stream flatMap0(final Function> mapper) {
return new IteratorStream<>(new ExIterator() {
private Iterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public R next() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.next();
}
}, closeHandlers);
}
@Override
CharStream flatMapToChar0(final Function mapper) {
return new IteratorCharStream(new ExCharIterator() {
private CharIterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public char nextChar() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextChar();
}
}, closeHandlers);
}
@Override
ByteStream flatMapToByte0(final Function mapper) {
return new IteratorByteStream(new ExByteIterator() {
private ByteIterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public byte nextByte() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextByte();
}
}, closeHandlers);
}
@Override
ShortStream flatMapToShort0(final Function mapper) {
return new IteratorShortStream(new ExShortIterator() {
private ShortIterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public short nextShort() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextShort();
}
}, closeHandlers);
}
@Override
IntStream flatMapToInt0(final Function mapper) {
return new IteratorIntStream(new ExIntIterator() {
private IntIterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public int nextInt() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextInt();
}
}, closeHandlers);
}
@Override
LongStream flatMapToLong0(final Function mapper) {
return new IteratorLongStream(new ExLongIterator() {
private LongIterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public long nextLong() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextLong();
}
}, closeHandlers);
}
@Override
FloatStream flatMapToFloat0(final Function mapper) {
return new IteratorFloatStream(new ExFloatIterator() {
private FloatIterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public float nextFloat() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextFloat();
}
}, closeHandlers);
}
@Override
DoubleStream flatMapToDouble0(final Function mapper) {
return new IteratorDoubleStream(new ExDoubleIterator() {
private DoubleIterator cur = null;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && elements.hasNext()) {
cur = mapper.apply(elements.next());
}
return cur != null && cur.hasNext();
}
@Override
public double nextDouble() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextDouble();
}
}, closeHandlers);
}
@Override
public Stream slidingMap(final BiFunction mapper, final int increment) {
final int windowSize = 2;
N.checkArgument(windowSize > 0 && increment > 0, "'windowSize'=%s and 'increment'=%s must not be less than 1", windowSize, increment);
return new IteratorStream<>(new ExIterator() {
private T prev = (T) NONE;
@Override
public boolean hasNext() {
if (increment > windowSize && prev != NONE) {
int skipNum = increment - windowSize;
while (skipNum-- > 0 && elements.hasNext()) {
elements.next();
}
prev = (T) NONE;
}
return elements.hasNext();
}
@Override
public R next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
if (increment == 1) {
return mapper.apply(prev == NONE ? elements.next() : prev, (prev = (elements.hasNext() ? elements.next() : null)));
} else {
return mapper.apply(elements.next(), (prev = (elements.hasNext() ? elements.next() : null)));
}
}
}, closeHandlers);
}
@Override
public Stream slidingMap(final TriFunction mapper, final int increment) {
final int windowSize = 3;
N.checkArgument(windowSize > 0 && increment > 0, "'windowSize'=%s and 'increment'=%s must not be less than 1", windowSize, increment);
return new IteratorStream<>(new ExIterator() {
private T prev = (T) NONE;
private T prev2 = (T) NONE;
@Override
public boolean hasNext() {
if (increment > windowSize && prev != NONE) {
int skipNum = increment - windowSize;
while (skipNum-- > 0 && elements.hasNext()) {
elements.next();
}
prev = (T) NONE;
}
return elements.hasNext();
}
@Override
public R next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
if (increment == 1) {
return mapper.apply(prev2 == NONE ? elements.next() : prev2,
(prev2 = (prev == NONE ? (elements.hasNext() ? elements.next() : null) : prev)),
(prev = (elements.hasNext() ? elements.next() : null)));
} else if (increment == 2) {
return mapper.apply(prev == NONE ? elements.next() : prev, (prev2 = (elements.hasNext() ? elements.next() : null)),
(prev = (elements.hasNext() ? elements.next() : null)));
} else {
return mapper.apply(elements.next(), (prev2 = (elements.hasNext() ? elements.next() : null)),
(prev = (elements.hasNext() ? elements.next() : null)));
}
}
}, closeHandlers);
}
@Override
public Stream> splitToList(final int size) {
return new IteratorStream<>(new ExIterator>() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public List next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
final List result = new ArrayList<>(size);
int cnt = 0;
while (cnt < size && elements.hasNext()) {
result.add(elements.next());
cnt++;
}
return result;
}
}, closeHandlers);
}
@Override
public Stream> splitToSet(final int size) {
return new IteratorStream<>(new ExIterator>() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public Set next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
final Set result = new HashSet<>(N.min(9, size));
int cnt = 0;
while (cnt < size && elements.hasNext()) {
result.add(elements.next());
cnt++;
}
return result;
}
}, closeHandlers);
}
@Override
public Stream> splitToList(final Predicate predicate) {
return new IteratorStream<>(new ExIterator>() {
private T next = (T) NONE;
private boolean preCondition = false;
@Override
public boolean hasNext() {
return next != NONE || elements.hasNext();
}
@Override
public List next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
final List result = new ArrayList<>();
if (next == NONE) {
next = elements.next();
}
while (next != NONE) {
if (result.size() == 0) {
result.add(next);
preCondition = predicate.test(next);
next = elements.hasNext() ? elements.next() : (T) NONE;
} else if (predicate.test(next) == preCondition) {
result.add(next);
next = elements.hasNext() ? elements.next() : (T) NONE;
} else {
break;
}
}
return result;
}
}, closeHandlers);
}
@Override
public Stream> splitToList(final U identity, final BiFunction predicate,
final Consumer identityUpdate) {
return new IteratorStream<>(new ExIterator>() {
private T next = (T) NONE;
private boolean preCondition = false;
@Override
public boolean hasNext() {
return next != NONE || elements.hasNext();
}
@Override
public List next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
final List result = new ArrayList<>();
if (next == NONE) {
next = elements.next();
}
while (next != NONE) {
if (result.size() == 0) {
result.add(next);
preCondition = predicate.apply(next, identity);
next = elements.hasNext() ? elements.next() : (T) NONE;
} else if (predicate.apply(next, identity) == preCondition) {
result.add(next);
next = elements.hasNext() ? elements.next() : (T) NONE;
} else {
if (identityUpdate != null) {
identityUpdate.accept(identity);
}
break;
}
}
return result;
}
}, closeHandlers);
}
@Override
public Stream> splitToSet(final U identity, final BiFunction predicate,
final Consumer identityUpdate) {
return new IteratorStream<>(new ExIterator>() {
private T next = (T) NONE;
private boolean preCondition = false;
@Override
public boolean hasNext() {
return next != NONE || elements.hasNext();
}
@Override
public Set next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
final Set result = new HashSet<>();
if (next == NONE) {
next = elements.next();
}
while (next != NONE) {
if (result.size() == 0) {
result.add(next);
preCondition = predicate.apply(next, identity);
next = elements.hasNext() ? elements.next() : (T) NONE;
} else if (predicate.apply(next, identity) == preCondition) {
result.add(next);
next = elements.hasNext() ? elements.next() : (T) NONE;
} else {
if (identityUpdate != null) {
identityUpdate.accept(identity);
}
break;
}
}
return result;
}
}, closeHandlers);
}
@Override
public Stream> slidingToList(final int windowSize, final int increment) {
N.checkArgument(windowSize > 0 && increment > 0, "'windowSize'=%s and 'increment'=%s must not be less than 1", windowSize, increment);
return new IteratorStream<>(new ExIterator>() {
private List prev = null;
@Override
public boolean hasNext() {
if (prev != null && increment > windowSize) {
int skipNum = increment - windowSize;
while (skipNum-- > 0 && elements.hasNext()) {
elements.next();
}
prev = null;
}
return elements.hasNext();
}
@Override
public List next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
final List result = new ArrayList<>(windowSize);
int cnt = 0;
if (prev != null && increment < windowSize) {
cnt = windowSize - increment;
if (cnt <= 8) {
for (int i = windowSize - cnt; i < windowSize; i++) {
result.add(prev.get(i));
}
} else {
result.addAll(prev.subList(windowSize - cnt, windowSize));
}
}
while (cnt++ < windowSize && elements.hasNext()) {
result.add(elements.next());
}
return prev = result;
}
}, closeHandlers);
}
@Override
public Stream top(int n) {
return top(n, OBJECT_COMPARATOR);
}
@Override
public Stream top(final int n, final Comparator comparator) {
N.checkArgument(n > 0, "'n' must be bigger than 0");
return new IteratorStream<>(new ExIterator() {
T[] a = null;
int cursor = 0;
int toIndex;
@Override
public boolean hasNext() {
if (a == null) {
top();
}
return cursor < toIndex;
}
@Override
public T next() {
if (a == null) {
top();
}
if (cursor >= toIndex) {
throw new NoSuchElementException();
}
return a[cursor++];
}
@Override
public long count() {
if (a == null) {
top();
}
return toIndex - cursor;
}
@Override
public void skip(long n) {
if (a == null) {
top();
}
cursor = n < toIndex - cursor ? cursor + (int) n : toIndex;
}
@Override
public A[] toArray(A[] b) {
if (a == null) {
top();
}
b = b.length >= toIndex - cursor ? b : (A[]) N.newArray(b.getClass().getComponentType(), toIndex - cursor);
N.copy(a, cursor, b, 0, toIndex - cursor);
return b;
}
private void top() {
if (sorted && isSameComparator(comparator, cmp)) {
final LinkedList queue = new LinkedList<>();
while (elements.hasNext()) {
if (queue.size() >= n) {
queue.poll();
}
queue.offer(elements.next());
}
a = (T[]) queue.toArray();
} else {
final Comparator> pairCmp = new Comparator>() {
@Override
public int compare(final Indexed o1, final Indexed o2) {
return N.compare(o1.value(), o2.value(), comparator);
}
};
final Queue> heap = new PriorityQueue<>(n, pairCmp);
Indexed pair = null;
for (long i = 0; elements.hasNext(); i++) {
pair = Indexed.of(elements.next(), i);
if (heap.size() >= n) {
if (pairCmp.compare(pair, heap.peek()) > 0) {
heap.poll();
heap.offer(pair);
}
} else {
heap.offer(pair);
}
}
final Indexed[] arrayOfPair = heap.toArray(new Indexed[heap.size()]);
N.sort(arrayOfPair, new Comparator>() {
@Override
public int compare(final Indexed o1, final Indexed o2) {
return N.compare(o1.longIndex(), o2.longIndex());
}
});
a = (T[]) new Object[arrayOfPair.length];
for (int i = 0, len = arrayOfPair.length; i < len; i++) {
a[i] = arrayOfPair[i].value();
}
}
toIndex = a.length;
}
}, closeHandlers, sorted, cmp);
}
@Override
public Stream sorted() {
return sorted(OBJECT_COMPARATOR);
}
@Override
public Stream sorted(final Comparator comparator) {
if (sorted && isSameComparator(comparator, cmp)) {
return this;
}
return new IteratorStream<>(new ExIterator() {
T[] a = null;
int toIndex = 0;
int cursor = 0;
@Override
public boolean hasNext() {
if (a == null) {
sort();
}
return cursor < toIndex;
}
@Override
public T next() {
if (a == null) {
sort();
}
if (cursor >= toIndex) {
throw new NoSuchElementException();
}
return a[cursor++];
}
@Override
public long count() {
if (a == null) {
sort();
}
return toIndex - cursor;
}
@Override
public void skip(long n) {
if (a == null) {
sort();
}
cursor = n < toIndex - cursor ? cursor + (int) n : toIndex;
}
@Override
public A[] toArray(A[] b) {
if (a == null) {
sort();
}
if (b.getClass().equals(a.getClass()) && b.length < toIndex - cursor) {
if (cursor == 0) {
return (A[]) a;
} else {
return (A[]) N.copyOfRange(a, cursor, toIndex);
}
} else {
if (b.length < toIndex - cursor) {
b = N.newArray(b.getClass().getComponentType(), toIndex - cursor);
}
N.copy(a, cursor, b, 0, toIndex - cursor);
return b;
}
}
private void sort() {
a = (T[]) elements.toArray(N.EMPTY_OBJECT_ARRAY);
toIndex = a.length;
if (comparator == null) {
N.sort(a);
} else {
N.sort(a, comparator);
}
}
}, closeHandlers, true, comparator);
}
@Override
public Stream peek(final Consumer action) {
return new IteratorStream<>(new ExIterator() {
@Override
public boolean hasNext() {
return elements.hasNext();
}
@Override
public T next() {
final T next = elements.next();
action.accept(next);
return next;
}
}, closeHandlers, sorted, cmp);
}
@Override
public Stream limit(final long maxSize) {
if (maxSize < 0) {
throw new IllegalArgumentException("'maxSize' can't be negative: " + maxSize);
}
return new IteratorStream<>(new ExIterator() {
private long cnt = 0;
@Override
public boolean hasNext() {
return cnt < maxSize && elements.hasNext();
}
@Override
public T next() {
if (cnt >= maxSize) {
throw new NoSuchElementException();
}
cnt++;
return elements.next();
}
@Override
public void skip(long n) {
elements.skip(n);
}
}, closeHandlers, sorted, cmp);
}
@Override
public Stream skip(final long n) {
if (n < 0) {
throw new IllegalArgumentException("The skipped number can't be negative: " + n);
} else if (n == 0) {
return this;
}
return new IteratorStream<>(new ExIterator() {
private boolean skipped = false;
@Override
public boolean hasNext() {
if (skipped == false) {
elements.skip(n);
skipped = true;
}
return elements.hasNext();
}
@Override
public T next() {
if (skipped == false) {
elements.skip(n);
skipped = true;
}
return elements.next();
}
@Override
public long count() {
if (skipped == false) {
elements.skip(n);
skipped = true;
}
return elements.count();
}
@Override
public void skip(long n2) {
if (skipped == false) {
elements.skip(n);
skipped = true;
}
elements.skip(n2);
}
@Override
public A[] toArray(A[] a) {
if (skipped == false) {
elements.skip(n);
skipped = true;
}
return elements.toArray(a);
}
}, closeHandlers, sorted, cmp);
}
@Override
public void forEach(Consumer action) {
while (elements.hasNext()) {
action.accept(elements.next());
}
}
@Override
public R forEach(R seed, BiFunction accumulator, BiPredicate conditionToBreak) {
R result = seed;
T next = null;
while (elements.hasNext()) {
next = elements.next();
result = accumulator.apply(result, next);
if (conditionToBreak.test(result, next)) {
break;
}
}
return result;
}
@Override
public void forEachPair(final BiConsumer action, final int increment) {
final int windowSize = 2;
N.checkArgument(windowSize > 0 && increment > 0, "'windowSize'=%s and 'increment'=%s must not be less than 1", windowSize, increment);
T prev = (T) NONE;
while (elements.hasNext()) {
if (increment > windowSize && prev != NONE) {
int skipNum = increment - windowSize;
while (skipNum-- > 0 && elements.hasNext()) {
elements.next();
}
if (elements.hasNext() == false) {
break;
}
prev = (T) NONE;
}
if (increment == 1) {
action.accept(prev == NONE ? elements.next() : prev, (prev = (elements.hasNext() ? elements.next() : null)));
} else {
action.accept(elements.next(), (prev = (elements.hasNext() ? elements.next() : null)));
}
}
}
@Override
public void forEachTriple(final TriConsumer action, final int increment) {
final int windowSize = 3;
N.checkArgument(windowSize > 0 && increment > 0, "'windowSize'=%s and 'increment'=%s must not be less than 1", windowSize, increment);
T prev = (T) NONE;
T prev2 = (T) NONE;
while (elements.hasNext()) {
if (increment > windowSize && prev != NONE) {
int skipNum = increment - windowSize;
while (skipNum-- > 0 && elements.hasNext()) {
elements.next();
}
if (elements.hasNext() == false) {
break;
}
prev = (T) NONE;
}
if (increment == 1) {
action.accept(prev2 == NONE ? elements.next() : prev2, (prev2 = (prev == NONE ? (elements.hasNext() ? elements.next() : null) : prev)),
(prev = (elements.hasNext() ? elements.next() : null)));
} else if (increment == 2) {
action.accept(prev == NONE ? elements.next() : prev, (prev2 = (elements.hasNext() ? elements.next() : null)),
(prev = (elements.hasNext() ? elements.next() : null)));
} else {
action.accept(elements.next(), (prev2 = (elements.hasNext() ? elements.next() : null)), (prev = (elements.hasNext() ? elements.next() : null)));
}
}
}
@Override
public Object[] toArray() {
return toArray(N.EMPTY_OBJECT_ARRAY);
}
A[] toArray(A[] a) {
return elements.toArray(a);
}
@Override
public A[] toArray(IntFunction generator) {
return toArray(generator.apply(0));
}
@Override
public List toList() {
final List result = new ArrayList<>();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public > R toList(Supplier supplier) {
final R result = supplier.get();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public Set toSet() {
final Set result = new HashSet<>();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public > R toSet(Supplier supplier) {
final R result = supplier.get();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public Multiset toMultiset() {
final Multiset result = new Multiset<>();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public Multiset toMultiset(Supplier> supplier) {
final Multiset result = supplier.get();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public LongMultiset toLongMultiset() {
final LongMultiset result = new LongMultiset<>();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public LongMultiset toLongMultiset(Supplier> supplier) {
final LongMultiset result = supplier.get();
while (elements.hasNext()) {
result.add(elements.next());
}
return result;
}
@Override
public > M toMap(Function keyExtractor, Function valueMapper,
BinaryOperator mergeFunction, Supplier mapFactory) {
final M result = mapFactory.get();
T element = null;
while (elements.hasNext()) {
element = elements.next();
Collectors.merge(result, keyExtractor.apply(element), valueMapper.apply(element), mergeFunction);
}
return result;
}
@Override
public > M toMap(final Function classifier, final Collector downstream,
final Supplier mapFactory) {
final M result = mapFactory.get();
final Supplier downstreamSupplier = downstream.supplier();
final BiConsumer downstreamAccumulator = downstream.accumulator();
final Map intermediate = (Map) result;
K key = null;
A v = null;
T element = null;
while (elements.hasNext()) {
element = elements.next();
key = N.requireNonNull(classifier.apply(element), "element cannot be mapped to a null key");
if ((v = intermediate.get(key)) == null) {
if ((v = downstreamSupplier.get()) != null) {
intermediate.put(key, v);
}
}
downstreamAccumulator.accept(v, element);
}
final BiFunction function = new BiFunction() {
@Override
public A apply(K k, A v) {
return (A) downstream.finisher().apply(v);
}
};
Collectors.replaceAll(intermediate, function);
return result;
}
@Override
public > Multimap toMultimap(Function keyExtractor,
Function valueMapper, Supplier> mapFactory) {
final Multimap result = mapFactory.get();
T element = null;
while (elements.hasNext()) {
element = elements.next();
result.put(keyExtractor.apply(element), valueMapper.apply(element));
}
return result;
}
@Override
public T reduce(T identity, BinaryOperator accumulator) {
T result = identity;
while (elements.hasNext()) {
result = accumulator.apply(result, elements.next());
}
return result;
}
@Override
public NullabLe reduce(BinaryOperator accumulator) {
if (elements.hasNext() == false) {
NullabLe.empty();
}
T result = elements.next();
while (elements.hasNext()) {
result = accumulator.apply(result, elements.next());
}
return NullabLe.of(result);
}
@Override
public U reduce(U identity, BiFunction accumulator, BinaryOperator combiner) {
U result = identity;
while (elements.hasNext()) {
result = accumulator.apply(result, elements.next());
}
return result;
}
@Override
public R collect(Supplier supplier, BiConsumer accumulator, BiConsumer combiner) {
final R result = supplier.get();
while (elements.hasNext()) {
accumulator.accept(result, elements.next());
}
return result;
}
@Override
public R collect(Collector collector) {
final A container = collector.supplier().get();
final BiConsumer accumulator = collector.accumulator();
while (elements.hasNext()) {
accumulator.accept(container, elements.next());
}
return collector.finisher().apply(container);
}
@Override
public NullabLe head() {
if (head == null) {
head = elements.hasNext() ? NullabLe.of(elements.next()) : NullabLe. empty();
tail = new IteratorStream<>(elements, closeHandlers, sorted, cmp);
}
return head;
}
@Override
public Stream tail() {
if (tail == null) {
head = elements.hasNext() ? NullabLe.of(elements.next()) : NullabLe. empty();
tail = new IteratorStream<>(elements, closeHandlers, sorted, cmp);
}
return tail;
}
@Override
public Stream head2() {
if (head2 == null) {
final Object[] a = this.toArray();
head2 = new ArrayStream<>((T[]) a, 0, a.length == 0 ? 0 : a.length - 1, closeHandlers, sorted, cmp);
tail2 = a.length == 0 ? NullabLe. empty() : NullabLe.of((T) a[a.length - 1]);
}
return head2;
}
@Override
public NullabLe tail2() {
if (tail2 == null) {
final Object[] a = this.toArray();
head2 = new ArrayStream<>((T[]) a, 0, a.length == 0 ? 0 : a.length - 1, closeHandlers, sorted, cmp);
tail2 = a.length == 0 ? NullabLe. empty() : NullabLe.of((T) a[a.length - 1]);
}
return tail2;
}
@Override
public Stream last(final int n) {
N.checkArgument(n >= 0, "'n' can't be negative");
if (n == 0) {
return new IteratorStream<>(ExIterator.EMPTY, closeHandlers, sorted, cmp);
}
final Deque dqueue = n <= 1024 ? new ArrayDeque(n) : new LinkedList();
while (elements.hasNext()) {
if (dqueue.size() >= n) {
dqueue.pollFirst();
}
dqueue.offerLast(elements.next());
}
return new IteratorStream<>(dqueue.iterator(), closeHandlers, sorted, cmp);
}
@Override
public Stream skipLast(final int n) {
N.checkArgument(n >= 0, "'n' can't be negative");
if (n == 0) {
return this;
}
return new IteratorStream<>(new ExIterator() {
private Deque dqueue = null;
@Override
public boolean hasNext() {
if (dqueue == null) {
dqueue = n <= 1024 ? new ArrayDeque(n) : new LinkedList();
while (dqueue.size() < n && elements.hasNext()) {
dqueue.offerLast(elements.next());
}
}
return elements.hasNext();
}
@Override
public T next() {
if (hasNext() == false) {
throw new NoSuchElementException();
}
dqueue.offerLast(elements.next());
return dqueue.pollFirst();
}
}, closeHandlers, sorted, cmp);
}
@Override
public NullabLe min(Comparator comparator) {
if (elements.hasNext() == false) {
return NullabLe.empty();
} else if (sorted && isSameComparator(comparator, cmp)) {
return NullabLe.of(elements.next());
}
comparator = comparator == null ? OBJECT_COMPARATOR : comparator;
T candidate = elements.next();
T next = null;
while (elements.hasNext()) {
next = elements.next();
if (comparator.compare(next, candidate) < 0) {
candidate = next;
}
}
return NullabLe.of(candidate);
}
@Override
public NullabLe max(Comparator comparator) {
if (elements.hasNext() == false) {
return NullabLe.empty();
} else if (sorted && isSameComparator(comparator, cmp)) {
T next = null;
while (elements.hasNext()) {
next = elements.next();
}
return NullabLe.of(next);
}
comparator = comparator == null ? OBJECT_COMPARATOR : comparator;
T candidate = elements.next();
T next = null;
while (elements.hasNext()) {
next = elements.next();
if (comparator.compare(next, candidate) > 0) {
candidate = next;
}
}
return NullabLe.of(candidate);
}
@Override
public NullabLe kthLargest(int k, Comparator comparator) {
N.checkArgument(k > 0, "'k' must be bigger than 0");
if (elements.hasNext() == false) {
return NullabLe.empty();
} else if (sorted && isSameComparator(comparator, cmp)) {
final LinkedList queue = new LinkedList<>();
while (elements.hasNext()) {
if (queue.size() >= k) {
queue.poll();
}
queue.offer(elements.next());
}
return queue.size() < k ? (NullabLe) NullabLe.empty() : NullabLe.of(queue.peek());
}
comparator = comparator == null ? OBJECT_COMPARATOR : comparator;
final Queue queue = new PriorityQueue<>(k, comparator);
T e = null;
while (elements.hasNext()) {
e = elements.next();
if (queue.size() < k) {
queue.offer(e);
} else {
if (N.compare(e, queue.peek(), comparator) > 0) {
queue.poll();
queue.offer(e);
}
}
}
return queue.size() < k ? (NullabLe) NullabLe.empty() : NullabLe.of(queue.peek());
}
@Override
public long count() {
return elements.count();
}
@Override
public boolean anyMatch(Predicate predicate) {
while (elements.hasNext()) {
if (predicate.test(elements.next())) {
return true;
}
}
return false;
}
@Override
public boolean allMatch(Predicate predicate) {
while (elements.hasNext()) {
if (predicate.test(elements.next()) == false) {
return false;
}
}
return true;
}
@Override
public boolean noneMatch(Predicate predicate) {
while (elements.hasNext()) {
if (predicate.test(elements.next())) {
return false;
}
}
return true;
}
@Override
public NullabLe findFirst(Predicate predicate) {
while (elements.hasNext()) {
T e = elements.next();
if (predicate.test(e)) {
return NullabLe.of(e);
}
}
return (NullabLe) NullabLe.empty();
}
@Override
public NullabLe findLast(Predicate predicate) {
if (elements.hasNext() == false) {
return (NullabLe) NullabLe.empty();
}
boolean hasResult = false;
T e = null;
T result = null;
while (elements.hasNext()) {
e = elements.next();
if (predicate.test(e)) {
result = e;
hasResult = true;
}
}
return hasResult ? NullabLe.of(result) : (NullabLe) NullabLe.empty();
}
/**
* Returns a Stream with elements from a temporary queue which is filled by reading the elements from the specified iterator asynchronously.
*
* @param stream
* @param queueSize Default value is 8
* @return
*/
@Override
public Stream queued(int queueSize) {
final Iterator iter = iterator();
if (iter instanceof QueuedIterator && ((QueuedIterator) iter).max() >= queueSize) {
return this;
} else {
return new IteratorStream<>(Stream.parallelConcat(Arrays.asList(iter), queueSize, asyncExecutor), closeHandlers, sorted, cmp);
}
}
@Override
ExIterator exIterator() {
return elements;
}
@Override
public Stream parallel(int maxThreadNum, Splitor splitor) {
if (maxThreadNum < 1 || maxThreadNum > MAX_THREAD_NUM_PER_OPERATION) {
throw new IllegalArgumentException("'maxThreadNum' must not less than 1 or exceeded: " + MAX_THREAD_NUM_PER_OPERATION);
}
return new ParallelIteratorStream<>(elements, closeHandlers, sorted, cmp, maxThreadNum, splitor);
}
@Override
public Stream onClose(Runnable closeHandler) {
final Set newCloseHandlers = new LocalLinkedHashSet<>(N.isNullOrEmpty(this.closeHandlers) ? 1 : this.closeHandlers.size() + 1);
if (N.notNullOrEmpty(this.closeHandlers)) {
newCloseHandlers.addAll(this.closeHandlers);
}
newCloseHandlers.add(closeHandler);
return new IteratorStream<>(elements, newCloseHandlers, sorted, cmp);
}
}
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