com.landawn.abacus.util.stream.CharStream Maven / Gradle / Ivy
Show all versions of abacus-android Show documentation
/*
* Copyright (C) 2016, 2017, 2018, 2019 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.security.SecureRandom;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.Random;
import com.landawn.abacus.annotation.SequentialOnly;
import com.landawn.abacus.util.CharIterator;
import com.landawn.abacus.util.CharList;
import com.landawn.abacus.util.CharMatrix;
import com.landawn.abacus.util.CharSummaryStatistics;
import com.landawn.abacus.util.ContinuableFuture;
import com.landawn.abacus.util.Fn.Fnn;
import com.landawn.abacus.util.IOUtil;
import com.landawn.abacus.util.IndexedChar;
import com.landawn.abacus.util.MutableInt;
import com.landawn.abacus.util.N;
import com.landawn.abacus.util.Nth;
import com.landawn.abacus.util.Pair;
import com.landawn.abacus.util.Percentage;
import com.landawn.abacus.util.StringUtil;
import com.landawn.abacus.util.Try;
import com.landawn.abacus.util.u.Holder;
import com.landawn.abacus.util.u.Optional;
import com.landawn.abacus.util.u.OptionalChar;
import com.landawn.abacus.util.u.OptionalDouble;
import com.landawn.abacus.util.function.BiConsumer;
import com.landawn.abacus.util.function.BinaryOperator;
import com.landawn.abacus.util.function.BooleanSupplier;
import com.landawn.abacus.util.function.CharBiFunction;
import com.landawn.abacus.util.function.CharBiPredicate;
import com.landawn.abacus.util.function.CharBinaryOperator;
import com.landawn.abacus.util.function.CharConsumer;
import com.landawn.abacus.util.function.CharFunction;
import com.landawn.abacus.util.function.CharNFunction;
import com.landawn.abacus.util.function.CharPredicate;
import com.landawn.abacus.util.function.CharSupplier;
import com.landawn.abacus.util.function.CharTernaryOperator;
import com.landawn.abacus.util.function.CharToIntFunction;
import com.landawn.abacus.util.function.CharUnaryOperator;
import com.landawn.abacus.util.function.Function;
import com.landawn.abacus.util.function.ObjCharConsumer;
import com.landawn.abacus.util.function.Supplier;
import com.landawn.abacus.util.function.ToCharFunction;
/**
* The Stream will be automatically closed after execution(A terminal method is executed/triggered).
*
*
* @see Stream
*/
public abstract class CharStream
extends StreamBase {
static final Random RAND = new SecureRandom();
CharStream(final boolean sorted, final Collection closeHandlers) {
super(sorted, null, closeHandlers);
}
/**
* Returns a stream consisting of the results of applying the given
* function to the elements of this stream.
*
* This is an intermediate
* operation.
*
* @param mapper a non-interfering,
* stateless
* function to apply to each element
* @return the new stream
*/
public abstract CharStream map(CharUnaryOperator mapper);
/**
* Returns a {@code IntStream} consisting of the results of applying the
* given function to the elements of this stream.
*
*
This is an intermediate
* operation.
*
* @param mapper a non-interfering,
* stateless
* function to apply to each element
* @return the new stream
*/
public abstract IntStream mapToInt(CharToIntFunction mapper);
/**
* Returns an object-valued {@code Stream} consisting of the results of
* applying the given function to the elements of this stream.
*
*
This is an
* intermediate operation.
*
* @param the element type of the new stream
* @param mapper a non-interfering,
* stateless
* function to apply to each element
* @return the new stream
*/
public abstract Stream mapToObj(CharFunction mapper);
/**
* Returns a stream consisting of the results of replacing each element of
* this stream with the contents of a mapped stream produced by applying
* the provided mapping function to each element.
*
*
This is an intermediate
* operation.
*
* @param mapper a non-interfering,
* stateless
* function to apply to each element which produces an
* {@code CharStream} of new values
* @return the new stream
* @see Stream#flatMap(Function)
*/
public abstract CharStream flatMap(CharFunction mapper);
public abstract CharStream flattMap(CharFunction mapper);
public abstract IntStream flatMapToInt(CharFunction mapper);
public abstract Stream flatMapToObj(CharFunction> mapper);
public abstract Stream flattMapToObj(CharFunction> mapper);
public abstract Stream flatMappToObj(CharFunction mapper);
/**
* Note: copied from StreamEx: https://github.com/amaembo/streamex
*
*
*
* Returns a stream consisting of results of applying the given function to
* the ranges created from the source elements.
* This is a quasi-intermediate
* partial reduction operation.
*
* @param sameRange a non-interfering, stateless predicate to apply to
* the leftmost and next elements which returns true for elements
* which belong to the same range.
* @param mapper a non-interfering, stateless function to apply to the
* range borders and produce the resulting element. If value was
* not merged to the interval, then mapper will receive the same
* value twice, otherwise it will receive the leftmost and the
* rightmost values which were merged to the range.
* @return the new stream
* @see #collapse(CharBiPredicate, CharBinaryOperator)
* @see Stream#rangeMap(BiPredicate, BiFunction)
*/
@SequentialOnly
public abstract CharStream rangeMap(final CharBiPredicate sameRange, final CharBinaryOperator mapper);
/**
* Note: copied from StreamEx: https://github.com/amaembo/streamex
*
*
*
* Returns a stream consisting of results of applying the given function to
* the ranges created from the source elements.
* This is a quasi-intermediate
* partial reduction operation.
*
* @param sameRange a non-interfering, stateless predicate to apply to
* the leftmost and next elements which returns true for elements
* which belong to the same range.
* @param mapper a non-interfering, stateless function to apply to the
* range borders and produce the resulting element. If value was
* not merged to the interval, then mapper will receive the same
* value twice, otherwise it will receive the leftmost and the
* rightmost values which were merged to the range.
* @return the new stream
* @see Stream#rangeMap(BiPredicate, BiFunction)
*/
@SequentialOnly
public abstract Stream rangeMapp(final CharBiPredicate sameRange, final CharBiFunction mapper);
/**
* Merge series of adjacent elements which satisfy the given predicate using
* the merger function and return a new stream.
*
*
* This method only run sequentially, even in parallel stream.
*
* @param collapsible
* @return
*/
@SequentialOnly
public abstract Stream collapse(final CharBiPredicate collapsible);
/**
* Merge series of adjacent elements which satisfy the given predicate using
* the merger function and return a new stream.
*
*
* This method only run sequentially, even in parallel stream.
*
* @param collapsible
* @param mergeFunction
* @return
*/
@SequentialOnly
public abstract CharStream collapse(final CharBiPredicate collapsible, final CharBinaryOperator mergeFunction);
/**
* Returns a {@code Stream} produced by iterative application of a accumulation function
* to an initial element {@code init} and next element of the current stream.
* Produces a {@code Stream} consisting of {@code init}, {@code acc(init, value1)},
* {@code acc(acc(init, value1), value2)}, etc.
*
* This is an intermediate operation.
*
*
Example:
*
* accumulator: (a, b) -> a + b
* stream: [1, 2, 3, 4, 5]
* result: [1, 3, 6, 10, 15]
*
*
*
* This method only run sequentially, even in parallel stream.
*
* @param accumulator the accumulation function
* @return the new stream which has the extract same size as this stream.
*/
@SequentialOnly
public abstract CharStream scan(final CharBinaryOperator accumulator);
/**
* Returns a {@code Stream} produced by iterative application of a accumulation function
* to an initial element {@code init} and next element of the current stream.
* Produces a {@code Stream} consisting of {@code init}, {@code acc(init, value1)},
* {@code acc(acc(init, value1), value2)}, etc.
*
* This is an intermediate operation.
*
*
Example:
*
* init:10
* accumulator: (a, b) -> a + b
* stream: [1, 2, 3, 4, 5]
* result: [11, 13, 16, 20, 25]
*
*
*
* This method only run sequentially, even in parallel stream.
*
* @param init the initial value. it's only used once by accumulator to calculate the fist element in the returned stream.
* It will be ignored if this stream is empty and won't be the first element of the returned stream.
*
* @param accumulator the accumulation function
* @return the new stream which has the extract same size as this stream.
*/
@SequentialOnly
public abstract CharStream scan(final char init, final CharBinaryOperator accumulator);
/**
*
* @param init
* @param accumulator
* @param initIncluded
* @return
*/
@SequentialOnly
public abstract CharStream scan(final char init, final CharBinaryOperator accumulator, final boolean initIncluded);
public abstract CharList toCharList();
/**
*
* @param keyMapper
* @param valueMapper
* @return
* @see Collectors#toMap(Function, Function)
*/
public abstract Map toMap(CharFunction keyMapper, CharFunction valueMapper);
/**
*
* @param keyMapper
* @param valueMapper
* @param mapFactory
* @return
* @see Collectors#toMap(Function, Function, Supplier)
*/
public abstract > M toMap(CharFunction keyMapper, CharFunction valueMapper,
Supplier mapFactory);
/**
*
* @param keyMapper
* @param valueMapper
* @param mergeFunction
* @return
* @see Collectors#toMap(Function, Function, BinaryOperator)
*/
public abstract Map toMap(CharFunction keyMapper, CharFunction valueMapper, BinaryOperator mergeFunction);
/**
*
* @param keyMapper
* @param valueMapper
* @param mergeFunction
* @param mapFactory
* @return
* @see Collectors#toMap(Function, Function, BinaryOperator, Supplier)
*/
public abstract > M toMap(CharFunction keyMapper, CharFunction valueMapper,
BinaryOperator mergeFunction, Supplier mapFactory);
/**
*
* @param keyMapper
* @param downstream
* @return
* @see Collectors#groupingBy(Function, Collector)
*/
public abstract Map toMap(final CharFunction keyMapper, final Collector downstream);
/**
*
* @param keyMapper
* @param downstream
* @param mapFactory
* @return
* @see Collectors#groupingBy(Function, Collector, Supplier)
*/
public abstract > M toMap(final CharFunction keyMapper, final Collector downstream,
final Supplier mapFactory);
public abstract CharMatrix toMatrix();
/**
* Performs a reduction on the
* elements of this stream, using the provided identity value and an
* associative
* accumulation function, and returns the reduced value. This is equivalent
* to:
* {@code
* int result = identity;
* for (int element : this stream)
* result = accumulator.applyAsChar(result, element)
* return result;
* }
*
* but is not constrained to execute sequentially.
*
* The {@code identity} value must be an identity for the accumulator
* function. This means that for all {@code x},
* {@code accumulator.apply(identity, x)} is equal to {@code x}.
* The {@code accumulator} function must be an
* associative function.
*
*
This is a terminal
* operation.
*
* @apiNote Sum, min, max, and average are all special cases of reduction.
* Summing a stream of numbers can be expressed as:
*
*
{@code
* int sum = integers.reduce(0, (a, b) -> a+b);
* }
*
* or more compactly:
*
* {@code
* int sum = integers.reduce(0, Chareger::sum);
* }
*
* While this may seem a more roundabout way to perform an aggregation
* compared to simply mutating a running total in a loop, reduction
* operations parallelize more gracefully, without needing additional
* synchronization and with greatly reduced risk of data races.
*
* @param identity the identity value for the accumulating function
* @param op an associative,
* non-interfering,
* stateless
* function for combining two values
* @return the result of the reduction
* @see #sum()
* @see #min()
* @see #max()
* @see #average()
*/
public abstract char reduce(char identity, CharBinaryOperator op);
/**
* Performs a reduction on the
* elements of this stream, using an
* associative accumulation
* function, and returns an {@code OptionalChar} describing the reduced value,
* if any. This is equivalent to:
*
{@code
* boolean foundAny = false;
* int result = null;
* for (int element : this stream) {
* if (!foundAny) {
* foundAny = true;
* result = element;
* }
* else
* result = accumulator.applyAsChar(result, element);
* }
* return foundAny ? OptionalChar.of(result) : OptionalChar.empty();
* }
*
* but is not constrained to execute sequentially.
*
* The {@code accumulator} function must be an
* associative function.
*
*
This is a terminal
* operation.
*
* @param op an associative,
* non-interfering,
* stateless
* function for combining two values
* @return the result of the reduction
* @see #reduce(int, CharBinaryOperator)
*/
public abstract OptionalChar reduce(CharBinaryOperator op);
/**
* Performs a mutable
* reduction operation on the elements of this stream. A mutable
* reduction is one in which the reduced value is a mutable result container,
* such as an {@code ArrayList}, and elements are incorporated by updating
* the state of the result rather than by replacing the result. This
* produces a result equivalent to:
*
{@code
* R result = supplier.get();
* for (int element : this stream)
* accumulator.accept(result, element);
* return result;
* }
*
* Like {@link #reduce(int, CharBinaryOperator)}, {@code collect} operations
* can be parallelized without requiring additional synchronization.
*
*
This is a terminal
* operation.
*
* @param type of the result
* @param supplier a function that creates a new result container. For a
* parallel execution, this function may be called
* multiple times and must return a fresh value each time.
* @param accumulator an associative,
* non-interfering,
* stateless
* function for incorporating an additional element into a result
* @param combiner an associative,
* non-interfering,
* stateless
* function for combining two values, which must be
* compatible with the accumulator function
* @return the result of the reduction
* @see Stream#collect(Supplier, BiConsumer, BiConsumer)
*/
public abstract R collect(Supplier supplier, ObjCharConsumer accumulator, BiConsumer combiner);
/**
*
* @param supplier
* @param accumulator
* @return
*/
public abstract R collect(Supplier supplier, ObjCharConsumer accumulator);
public abstract void forEach(final Try.CharConsumer action) throws E;
public abstract boolean anyMatch(final Try.CharPredicate predicate) throws E;
public abstract boolean allMatch(final Try.CharPredicate predicate) throws E;
public abstract boolean noneMatch(final Try.CharPredicate predicate) throws E;
public abstract OptionalChar findFirst(final Try.CharPredicate predicate) throws E;
public abstract OptionalChar findLast(final Try.CharPredicate predicate) throws E;
public abstract OptionalChar findFirstOrLast(Try.CharPredicate predicateForFirst,
Try.CharPredicate predicateForLast) throws E, E2;
public abstract OptionalChar findAny(final Try.CharPredicate predicate) throws E;
/**
* Returns an {@code OptionalChar} describing the minimum element of this
* stream, or an empty optional if this stream is empty. This is a special
* case of a reduction
* and is equivalent to:
* {@code
* return reduce(Chareger::min);
* }
*
* This is a terminal operation.
*
* @return an {@code OptionalChar} containing the minimum element of this
* stream, or an empty {@code OptionalChar} if the stream is empty
*/
public abstract OptionalChar min();
/**
* Returns an {@code OptionalChar} describing the maximum element of this
* stream, or an empty optional if this stream is empty. This is a special
* case of a reduction
* and is equivalent to:
*
{@code
* return reduce(Chareger::max);
* }
*
* This is a terminal
* operation.
*
* @return an {@code OptionalChar} containing the maximum element of this
* stream, or an empty {@code OptionalChar} if the stream is empty
*/
public abstract OptionalChar max();
/**
*
* @param k
* @return OptionalByte.empty() if there is no element or count less than k, otherwise the kth largest element.
*/
public abstract OptionalChar kthLargest(int k);
public abstract int sum();
public abstract OptionalDouble average();
public abstract CharSummaryStatistics summarize();
public abstract Pair>> summarizeAndPercentiles();
/**
*
* @param b
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public abstract CharStream merge(final CharStream b, final CharBiFunction nextSelector);
public abstract CharStream zipWith(CharStream b, CharBinaryOperator zipFunction);
public abstract CharStream zipWith(CharStream b, CharStream c, CharTernaryOperator zipFunction);
public abstract CharStream zipWith(CharStream b, char valueForNoneA, char valueForNoneB, CharBinaryOperator zipFunction);
public abstract CharStream zipWith(CharStream b, CharStream c, char valueForNoneA, char valueForNoneB, char valueForNoneC, CharTernaryOperator zipFunction);
/**
* Returns a {@code LongStream} consisting of the elements of this stream,
* converted to {@code long}.
*
* This is an intermediate
* operation.
*
* @return a {@code LongStream} consisting of the elements of this stream,
* converted to {@code long}
*/
public abstract IntStream asIntStream();
/**
* Returns a {@code Stream} consisting of the elements of this stream,
* each boxed to an {@code Chareger}.
*
*
This is an intermediate
* operation.
*
* @return a {@code Stream} consistent of the elements of this stream,
* each boxed to an {@code Chareger}
*/
public abstract Stream boxed();
/**
* Remember to close this Stream after the iteration is done, if required.
*
* @return
*/
@SequentialOnly
@Override
public CharIterator iterator() {
return iteratorEx();
}
abstract CharIteratorEx iteratorEx();
@Override
public R __(Function transfer) {
return transfer.apply(this);
}
public static CharStream empty() {
return new ArrayCharStream(N.EMPTY_CHAR_ARRAY, true, null);
}
@SafeVarargs
public static CharStream of(final char... a) {
return N.isNullOrEmpty(a) ? empty() : new ArrayCharStream(a);
}
public static CharStream of(final char[] a, final int startIndex, final int endIndex) {
return N.isNullOrEmpty(a) && (startIndex == 0 && endIndex == 0) ? empty() : new ArrayCharStream(a, startIndex, endIndex);
}
/**
* Takes the chars in the specified String as the elements of the Stream
*
* @param str
* @return
*/
public static CharStream of(final CharSequence str) {
return N.isNullOrEmpty(str) ? empty() : of(str, 0, str.length());
}
/**
* Takes the chars in the specified String as the elements of the Stream
*
* @param str
* @param startIndex
* @param endIndex
* @return
*/
@SuppressWarnings("deprecation")
public static CharStream of(final CharSequence str, final int startIndex, final int endIndex) {
N.checkFromToIndex(startIndex, endIndex, N.len(str));
if (N.isNullOrEmpty(str)) {
return empty();
}
if (str instanceof String) {
return of(StringUtil.getCharsForReadOnly((String) str), startIndex, endIndex);
}
final CharIteratorEx iter = new CharIteratorEx() {
private int cursor = startIndex;
@Override
public boolean hasNext() {
return cursor < endIndex;
}
@Override
public char nextChar() {
return str.charAt(cursor++);
}
@Override
public long count() {
return endIndex - cursor;
}
};
return new IteratorCharStream(iter);
}
public static CharStream of(final Character[] a) {
return Stream.of(a).mapToChar(Fnn.unboxC());
}
public static CharStream of(final Character[] a, final int startIndex, final int endIndex) {
return Stream.of(a, startIndex, endIndex).mapToChar(Fnn.unboxC());
}
public static CharStream of(final Collection c) {
return Stream.of(c).mapToChar(Fnn.unboxC());
}
public static CharStream of(final CharIterator iterator) {
return iterator == null ? empty() : new IteratorCharStream(iterator);
}
/**
* Lazy evaluation.
* @param supplier
* @return
*/
public static CharStream of(final Supplier supplier) {
final CharIterator iter = new CharIteratorEx() {
private CharIterator iterator = null;
@Override
public boolean hasNext() {
if (iterator == null) {
init();
}
return iterator.hasNext();
}
@Override
public char nextChar() {
if (iterator == null) {
init();
}
return iterator.nextChar();
}
private void init() {
final CharList c = supplier.get();
if (N.isNullOrEmpty(c)) {
iterator = CharIterator.empty();
} else {
iterator = c.iterator();
}
}
};
return of(iter);
}
private static final Function flatMapper = new Function() {
@Override
public CharStream apply(char[] t) {
return CharStream.of(t);
}
};
private static final Function flatMappper = new Function() {
@Override
public CharStream apply(char[][] t) {
return CharStream.flat(t);
}
};
public static CharStream flat(final char[][] a) {
return N.isNullOrEmpty(a) ? empty() : Stream.of(a).flatMapToChar(flatMapper);
}
public static CharStream flat(final char[][] a, final boolean vertically) {
if (N.isNullOrEmpty(a)) {
return empty();
} else if (a.length == 1) {
return of(a[0]);
} else if (vertically == false) {
return Stream.of(a).flatMapToChar(flatMapper);
}
long n = 0;
for (char[] e : a) {
n += N.len(e);
}
if (n == 0) {
return empty();
}
final int rows = N.len(a);
final long count = n;
final CharIterator iter = new CharIteratorEx() {
private int rowNum = 0;
private int colNum = 0;
private long cnt = 0;
@Override
public boolean hasNext() {
return cnt < count;
}
@Override
public char nextChar() {
if (cnt++ >= count) {
throw new NoSuchElementException();
}
if (rowNum == rows) {
rowNum = 0;
colNum++;
}
while (a[rowNum] == null || colNum >= a[rowNum].length) {
if (rowNum < rows - 1) {
rowNum++;
} else {
rowNum = 0;
colNum++;
}
}
return a[rowNum++][colNum];
}
};
return of(iter);
}
public static CharStream flat(final char[][] a, final char valueForNone, final boolean vertically) {
if (N.isNullOrEmpty(a)) {
return empty();
} else if (a.length == 1) {
return of(a[0]);
}
long n = 0;
int maxLen = 0;
for (char[] e : a) {
n += N.len(e);
maxLen = N.max(maxLen, N.len(e));
}
if (n == 0) {
return empty();
}
final int rows = N.len(a);
final int cols = maxLen;
final long count = rows * cols;
CharIterator iter = null;
if (vertically) {
iter = new CharIteratorEx() {
private int rowNum = 0;
private int colNum = 0;
private long cnt = 0;
@Override
public boolean hasNext() {
return cnt < count;
}
@Override
public char nextChar() {
if (cnt++ >= count) {
throw new NoSuchElementException();
}
if (rowNum == rows) {
rowNum = 0;
colNum++;
}
if (a[rowNum] == null || colNum >= a[rowNum].length) {
rowNum++;
return valueForNone;
} else {
return a[rowNum++][colNum];
}
}
};
} else {
iter = new CharIteratorEx() {
private int rowNum = 0;
private int colNum = 0;
private long cnt = 0;
@Override
public boolean hasNext() {
return cnt < count;
}
@Override
public char nextChar() {
if (cnt++ >= count) {
throw new NoSuchElementException();
}
if (colNum >= cols) {
colNum = 0;
rowNum++;
}
if (a[rowNum] == null || colNum >= a[rowNum].length) {
colNum++;
return valueForNone;
} else {
return a[rowNum][colNum++];
}
}
};
}
return of(iter);
}
public static CharStream flat(final char[][][] a) {
return N.isNullOrEmpty(a) ? empty() : Stream.of(a).flatMapToChar(flatMappper);
}
public static CharStream range(final char startInclusive, final char endExclusive) {
if (startInclusive >= endExclusive) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private char next = startInclusive;
private int cnt = endExclusive * 1 - startInclusive;
@Override
public boolean hasNext() {
return cnt > 0;
}
@Override
public char nextChar() {
if (cnt-- <= 0) {
throw new NoSuchElementException();
}
return next++;
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
cnt = n >= cnt ? 0 : cnt - (int) n;
next += n;
}
@Override
public long count() {
return cnt;
}
@Override
public char[] toArray() {
final char[] result = new char[cnt];
for (int i = 0; i < cnt; i++) {
result[i] = next++;
}
cnt = 0;
return result;
}
});
}
public static CharStream range(final char startInclusive, final char endExclusive, final int by) {
if (by == 0) {
throw new IllegalArgumentException("'by' can't be zero");
}
if (endExclusive == startInclusive || endExclusive > startInclusive != by > 0) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private char next = startInclusive;
private int cnt = (endExclusive * 1 - startInclusive) / by + ((endExclusive * 1 - startInclusive) % by == 0 ? 0 : 1);
@Override
public boolean hasNext() {
return cnt > 0;
}
@Override
public char nextChar() {
if (cnt-- <= 0) {
throw new NoSuchElementException();
}
char result = next;
next += by;
return result;
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
cnt = n >= cnt ? 0 : cnt - (int) n;
next += n * by;
}
@Override
public long count() {
return cnt;
}
@Override
public char[] toArray() {
final char[] result = new char[cnt];
for (int i = 0; i < cnt; i++, next += by) {
result[i] = next;
}
cnt = 0;
return result;
}
});
}
public static CharStream rangeClosed(final char startInclusive, final char endInclusive) {
if (startInclusive > endInclusive) {
return empty();
} else if (startInclusive == endInclusive) {
return of(startInclusive);
}
return new IteratorCharStream(new CharIteratorEx() {
private char next = startInclusive;
private int cnt = endInclusive * 1 - startInclusive + 1;
@Override
public boolean hasNext() {
return cnt > 0;
}
@Override
public char nextChar() {
if (cnt-- <= 0) {
throw new NoSuchElementException();
}
return next++;
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
cnt = n >= cnt ? 0 : cnt - (int) n;
next += n;
}
@Override
public long count() {
return cnt;
}
@Override
public char[] toArray() {
final char[] result = new char[cnt];
for (int i = 0; i < cnt; i++) {
result[i] = next++;
}
cnt = 0;
return result;
}
});
}
public static CharStream rangeClosed(final char startInclusive, final char endInclusive, final int by) {
if (by == 0) {
throw new IllegalArgumentException("'by' can't be zero");
}
if (endInclusive == startInclusive) {
return of(startInclusive);
} else if (endInclusive > startInclusive != by > 0) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private char next = startInclusive;
private int cnt = (endInclusive * 1 - startInclusive) / by + 1;
@Override
public boolean hasNext() {
return cnt > 0;
}
@Override
public char nextChar() {
if (cnt-- <= 0) {
throw new NoSuchElementException();
}
char result = next;
next += by;
return result;
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
cnt = n >= cnt ? 0 : cnt - (int) n;
next += n * by;
}
@Override
public long count() {
return cnt;
}
@Override
public char[] toArray() {
final char[] result = new char[cnt];
for (int i = 0; i < cnt; i++, next += by) {
result[i] = next;
}
cnt = 0;
return result;
}
});
}
public static CharStream repeat(final char element, final long n) {
N.checkArgNotNegative(n, "n");
if (n == 0) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private long cnt = n;
@Override
public boolean hasNext() {
return cnt > 0;
}
@Override
public char nextChar() {
if (cnt-- <= 0) {
throw new NoSuchElementException();
}
return element;
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
cnt = n >= cnt ? 0 : cnt - (int) n;
}
@Override
public long count() {
return cnt;
}
@Override
public char[] toArray() {
final char[] result = new char[(int) cnt];
for (int i = 0; i < cnt; i++) {
result[i] = element;
}
cnt = 0;
return result;
}
});
}
public static CharStream random() {
final int mod = Character.MAX_VALUE + 1;
return generate(new CharSupplier() {
@Override
public char getAsChar() {
return (char) RAND.nextInt(mod);
}
});
}
public static CharStream random(final char startInclusive, final char endExclusive) {
if (startInclusive >= endExclusive) {
throw new IllegalArgumentException("'startInclusive' must be less than 'endExclusive'");
}
final int mod = endExclusive - startInclusive;
return generate(new CharSupplier() {
@Override
public char getAsChar() {
return (char) (RAND.nextInt(mod) + startInclusive);
}
});
}
public static CharStream random(final char[] candicates) {
if (N.isNullOrEmpty(candicates)) {
return empty();
} else if (candicates.length >= Integer.MAX_VALUE) {
throw new IllegalArgumentException();
}
final int n = candicates.length;
return generate(new CharSupplier() {
@Override
public char getAsChar() {
return candicates[RAND.nextInt(n)];
}
});
}
public static CharStream iterate(final BooleanSupplier hasNext, final CharSupplier next) {
N.checkArgNotNull(hasNext);
N.checkArgNotNull(next);
return new IteratorCharStream(new CharIteratorEx() {
private boolean hasNextVal = false;
@Override
public boolean hasNext() {
if (hasNextVal == false) {
hasNextVal = hasNext.getAsBoolean();
}
return hasNextVal;
}
@Override
public char nextChar() {
if (hasNextVal == false && hasNext() == false) {
throw new NoSuchElementException();
}
hasNextVal = false;
return next.getAsChar();
}
});
}
public static CharStream iterate(final char init, final BooleanSupplier hasNext, final CharUnaryOperator f) {
N.checkArgNotNull(hasNext);
N.checkArgNotNull(f);
return new IteratorCharStream(new CharIteratorEx() {
private char t = 0;
private boolean isFirst = true;
private boolean hasNextVal = false;
@Override
public boolean hasNext() {
if (hasNextVal == false) {
hasNextVal = hasNext.getAsBoolean();
}
return hasNextVal;
}
@Override
public char nextChar() {
if (hasNextVal == false && hasNext() == false) {
throw new NoSuchElementException();
}
hasNextVal = false;
if (isFirst) {
isFirst = false;
t = init;
} else {
t = f.applyAsChar(t);
}
return t;
}
});
}
/**
*
* @param init
* @param hasNext test if has next by hasNext.test(init) for first time and hasNext.test(f.apply(previous)) for remaining.
* @param f
* @return
*/
public static CharStream iterate(final char init, final CharPredicate hasNext, final CharUnaryOperator f) {
N.checkArgNotNull(hasNext);
N.checkArgNotNull(f);
return new IteratorCharStream(new CharIteratorEx() {
private char t = 0;
private char cur = 0;
private boolean isFirst = true;
private boolean hasMore = true;
private boolean hasNextVal = false;
@Override
public boolean hasNext() {
if (hasNextVal == false && hasMore) {
if (isFirst) {
isFirst = false;
hasNextVal = hasNext.test(cur = init);
} else {
hasNextVal = hasNext.test(cur = f.applyAsChar(t));
}
if (hasNextVal == false) {
hasMore = false;
}
}
return hasNextVal;
}
@Override
public char nextChar() {
if (hasNextVal == false && hasNext() == false) {
throw new NoSuchElementException();
}
t = cur;
hasNextVal = false;
return t;
}
});
}
public static CharStream iterate(final char init, final CharUnaryOperator f) {
N.checkArgNotNull(f);
return new IteratorCharStream(new CharIteratorEx() {
private char t = 0;
private boolean isFirst = true;
@Override
public boolean hasNext() {
return true;
}
@Override
public char nextChar() {
if (isFirst) {
isFirst = false;
t = init;
} else {
t = f.applyAsChar(t);
}
return t;
}
});
}
public static CharStream generate(final CharSupplier s) {
N.checkArgNotNull(s);
return new IteratorCharStream(new CharIteratorEx() {
@Override
public boolean hasNext() {
return true;
}
@Override
public char nextChar() {
return s.getAsChar();
}
});
}
@SafeVarargs
public static CharStream concat(final char[]... a) {
return N.isNullOrEmpty(a) ? empty() : new IteratorCharStream(new CharIteratorEx() {
private final Iterator iter = N.asList(a).iterator();
private CharIterator cur;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && iter.hasNext()) {
cur = CharIteratorEx.of(iter.next());
}
return cur != null && cur.hasNext();
}
@Override
public char nextChar() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextChar();
}
});
}
@SafeVarargs
public static CharStream concat(final CharIterator... a) {
return N.isNullOrEmpty(a) ? empty() : new IteratorCharStream(new CharIteratorEx() {
private final Iterator iter = N.asList(a).iterator();
private CharIterator cur;
@Override
public boolean hasNext() {
while ((cur == null || cur.hasNext() == false) && iter.hasNext()) {
cur = iter.next();
}
return cur != null && cur.hasNext();
}
@Override
public char nextChar() {
if ((cur == null || cur.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return cur.nextChar();
}
});
}
@SafeVarargs
public static CharStream concat(final CharStream... a) {
return N.isNullOrEmpty(a) ? empty() : concat(N.asList(a));
}
public static CharStream concat(final Collection c) {
return N.isNullOrEmpty(c) ? empty() : new IteratorCharStream(new CharIteratorEx() {
private final Iterator iterators = c.iterator();
private CharStream cur;
private CharIterator iter;
@Override
public boolean hasNext() {
while ((iter == null || iter.hasNext() == false) && iterators.hasNext()) {
if (cur != null) {
cur.close();
}
cur = iterators.next();
iter = cur.iterator();
}
return iter != null && iter.hasNext();
}
@Override
public char nextChar() {
if ((iter == null || iter.hasNext() == false) && hasNext() == false) {
throw new NoSuchElementException();
}
return iter.nextChar();
}
}).onClose(newCloseHandler(c));
}
/**
* Zip together the "a" and "b" arrays until one of them runs out of values.
* Each pair of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @return
*/
public static CharStream zip(final char[] a, final char[] b, final CharBinaryOperator zipFunction) {
if (N.isNullOrEmpty(a) || N.isNullOrEmpty(b)) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private final int len = N.min(N.len(a), N.len(b));
private int cursor = 0;
@Override
public boolean hasNext() {
return cursor < len;
}
@Override
public char nextChar() {
if (cursor >= len) {
throw new NoSuchElementException();
}
return zipFunction.applyAsChar(a[cursor], b[cursor++]);
}
});
}
/**
* Zip together the "a", "b" and "c" arrays until one of them runs out of values.
* Each triple of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @param c
* @return
*/
public static CharStream zip(final char[] a, final char[] b, final char[] c, final CharTernaryOperator zipFunction) {
if (N.isNullOrEmpty(a) || N.isNullOrEmpty(b) || N.isNullOrEmpty(c)) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private final int len = N.min(N.len(a), N.len(b), N.len(c));
private int cursor = 0;
@Override
public boolean hasNext() {
return cursor < len;
}
@Override
public char nextChar() {
if (cursor >= len) {
throw new NoSuchElementException();
}
return zipFunction.applyAsChar(a[cursor], b[cursor], c[cursor++]);
}
});
}
/**
* Zip together the "a" and "b" iterators until one of them runs out of values.
* Each pair of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @return
*/
public static CharStream zip(final CharIterator a, final CharIterator b, final CharBinaryOperator zipFunction) {
return new IteratorCharStream(new CharIteratorEx() {
@Override
public boolean hasNext() {
return a.hasNext() && b.hasNext();
}
@Override
public char nextChar() {
return zipFunction.applyAsChar(a.nextChar(), b.nextChar());
}
});
}
/**
* Zip together the "a", "b" and "c" iterators until one of them runs out of values.
* Each triple of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @return
*/
public static CharStream zip(final CharIterator a, final CharIterator b, final CharIterator c, final CharTernaryOperator zipFunction) {
return new IteratorCharStream(new CharIteratorEx() {
@Override
public boolean hasNext() {
return a.hasNext() && b.hasNext() && c.hasNext();
}
@Override
public char nextChar() {
return zipFunction.applyAsChar(a.nextChar(), b.nextChar(), c.nextChar());
}
});
}
/**
* Zip together the "a" and "b" streams until one of them runs out of values.
* Each pair of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @return
*/
public static CharStream zip(final CharStream a, final CharStream b, final CharBinaryOperator zipFunction) {
return zip(a.iteratorEx(), b.iteratorEx(), zipFunction).onClose(newCloseHandler(N.asList(a, b)));
}
/**
* Zip together the "a", "b" and "c" streams until one of them runs out of values.
* Each triple of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @return
*/
public static CharStream zip(final CharStream a, final CharStream b, final CharStream c, final CharTernaryOperator zipFunction) {
return zip(a.iteratorEx(), b.iteratorEx(), c.iteratorEx(), zipFunction).onClose(newCloseHandler(N.asList(a, b, c)));
}
/**
* Zip together the iterators until one of them runs out of values.
* Each array of values is combined into a single value using the supplied zipFunction function.
*
* @param c
* @param zipFunction
* @return
*/
public static CharStream zip(final Collection c, final CharNFunction zipFunction) {
return Stream.zip(c, zipFunction).mapToChar(ToCharFunction.UNBOX);
}
/**
* Zip together the "a" and "b" iterators until all of them runs out of values.
* Each pair of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @param valueForNoneA value to fill if "a" runs out of values first.
* @param valueForNoneB value to fill if "b" runs out of values first.
* @param zipFunction
* @return
*/
public static CharStream zip(final char[] a, final char[] b, final char valueForNoneA, final char valueForNoneB, final CharBinaryOperator zipFunction) {
if (N.isNullOrEmpty(a) && N.isNullOrEmpty(b)) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private final int aLen = N.len(a), bLen = N.len(b), len = N.max(aLen, bLen);
private int cursor = 0;
private char ret = 0;
@Override
public boolean hasNext() {
return cursor < len;
}
@Override
public char nextChar() {
if (cursor >= len) {
throw new NoSuchElementException();
}
ret = zipFunction.applyAsChar(cursor < aLen ? a[cursor] : valueForNoneA, cursor < bLen ? b[cursor] : valueForNoneB);
cursor++;
return ret;
}
});
}
/**
* Zip together the "a", "b" and "c" iterators until all of them runs out of values.
* Each triple of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @param c
* @param valueForNoneA value to fill if "a" runs out of values.
* @param valueForNoneB value to fill if "b" runs out of values.
* @param valueForNoneC value to fill if "c" runs out of values.
* @param zipFunction
* @return
*/
public static CharStream zip(final char[] a, final char[] b, final char[] c, final char valueForNoneA, final char valueForNoneB, final char valueForNoneC,
final CharTernaryOperator zipFunction) {
if (N.isNullOrEmpty(a) && N.isNullOrEmpty(b) && N.isNullOrEmpty(c)) {
return empty();
}
return new IteratorCharStream(new CharIteratorEx() {
private final int aLen = N.len(a), bLen = N.len(b), cLen = N.len(c), len = N.max(aLen, bLen, cLen);
private int cursor = 0;
private char ret = 0;
@Override
public boolean hasNext() {
return cursor < len;
}
@Override
public char nextChar() {
if (cursor >= len) {
throw new NoSuchElementException();
}
ret = zipFunction.applyAsChar(cursor < aLen ? a[cursor] : valueForNoneA, cursor < bLen ? b[cursor] : valueForNoneB,
cursor < cLen ? c[cursor] : valueForNoneC);
cursor++;
return ret;
}
});
}
/**
* Zip together the "a" and "b" iterators until all of them runs out of values.
* Each pair of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @param valueForNoneA value to fill if "a" runs out of values first.
* @param valueForNoneB value to fill if "b" runs out of values first.
* @param zipFunction
* @return
*/
public static CharStream zip(final CharIterator a, final CharIterator b, final char valueForNoneA, final char valueForNoneB,
final CharBinaryOperator zipFunction) {
return new IteratorCharStream(new CharIteratorEx() {
@Override
public boolean hasNext() {
return a.hasNext() || b.hasNext();
}
@Override
public char nextChar() {
if (a.hasNext()) {
return zipFunction.applyAsChar(a.nextChar(), b.hasNext() ? b.nextChar() : valueForNoneB);
} else {
return zipFunction.applyAsChar(valueForNoneA, b.nextChar());
}
}
});
}
/**
* Zip together the "a", "b" and "c" iterators until all of them runs out of values.
* Each triple of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @param c
* @param valueForNoneA value to fill if "a" runs out of values.
* @param valueForNoneB value to fill if "b" runs out of values.
* @param valueForNoneC value to fill if "c" runs out of values.
* @param zipFunction
* @return
*/
public static CharStream zip(final CharIterator a, final CharIterator b, final CharIterator c, final char valueForNoneA, final char valueForNoneB,
final char valueForNoneC, final CharTernaryOperator zipFunction) {
return new IteratorCharStream(new CharIteratorEx() {
@Override
public boolean hasNext() {
return a.hasNext() || b.hasNext() || c.hasNext();
}
@Override
public char nextChar() {
if (a.hasNext()) {
return zipFunction.applyAsChar(a.nextChar(), b.hasNext() ? b.nextChar() : valueForNoneB, c.hasNext() ? c.nextChar() : valueForNoneC);
} else if (b.hasNext()) {
return zipFunction.applyAsChar(valueForNoneA, b.nextChar(), c.hasNext() ? c.nextChar() : valueForNoneC);
} else {
return zipFunction.applyAsChar(valueForNoneA, valueForNoneB, c.nextChar());
}
}
});
}
/**
* Zip together the "a" and "b" iterators until all of them runs out of values.
* Each pair of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @param valueForNoneA value to fill if "a" runs out of values first.
* @param valueForNoneB value to fill if "b" runs out of values first.
* @param zipFunction
* @return
*/
public static CharStream zip(final CharStream a, final CharStream b, final char valueForNoneA, final char valueForNoneB,
final CharBinaryOperator zipFunction) {
return zip(a.iteratorEx(), b.iteratorEx(), valueForNoneA, valueForNoneB, zipFunction).onClose(newCloseHandler(N.asList(a, b)));
}
/**
* Zip together the "a", "b" and "c" iterators until all of them runs out of values.
* Each triple of values is combined into a single value using the supplied zipFunction function.
*
* @param a
* @param b
* @param c
* @param valueForNoneA value to fill if "a" runs out of values.
* @param valueForNoneB value to fill if "b" runs out of values.
* @param valueForNoneC value to fill if "c" runs out of values.
* @param zipFunction
* @return
*/
public static CharStream zip(final CharStream a, final CharStream b, final CharStream c, final char valueForNoneA, final char valueForNoneB,
final char valueForNoneC, final CharTernaryOperator zipFunction) {
return zip(a.iteratorEx(), b.iteratorEx(), c.iteratorEx(), valueForNoneA, valueForNoneB, valueForNoneC, zipFunction)
.onClose(newCloseHandler(N.asList(a, b, c)));
}
/**
* Zip together the iterators until all of them runs out of values.
* Each array of values is combined into a single value using the supplied zipFunction function.
*
* @param c
* @param valuesForNone value to fill for any iterator runs out of values.
* @param zipFunction
* @return
*/
public static CharStream zip(final Collection c, final char[] valuesForNone, final CharNFunction zipFunction) {
return Stream.zip(c, valuesForNone, zipFunction).mapToChar(ToCharFunction.UNBOX);
}
/**
*
* @param a
* @param b
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream merge(final char[] a, final char[] b, final CharBiFunction nextSelector) {
if (N.isNullOrEmpty(a)) {
return of(b);
} else if (N.isNullOrEmpty(b)) {
return of(a);
}
return new IteratorCharStream(new CharIteratorEx() {
private final int lenA = a.length;
private final int lenB = b.length;
private int cursorA = 0;
private int cursorB = 0;
@Override
public boolean hasNext() {
return cursorA < lenA || cursorB < lenB;
}
@Override
public char nextChar() {
if (cursorA < lenA) {
if (cursorB < lenB) {
if (nextSelector.apply(a[cursorA], b[cursorB]) == Nth.FIRST) {
return a[cursorA++];
} else {
return b[cursorB++];
}
} else {
return a[cursorA++];
}
} else if (cursorB < lenB) {
return b[cursorB++];
} else {
throw new NoSuchElementException();
}
}
});
}
/**
*
* @param a
* @param b
* @param c
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream merge(final char[] a, final char[] b, final char[] c, final CharBiFunction nextSelector) {
return merge(merge(a, b, nextSelector).iteratorEx(), CharStream.of(c).iteratorEx(), nextSelector);
}
/**
*
* @param a
* @param b
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream merge(final CharIterator a, final CharIterator b, final CharBiFunction nextSelector) {
return new IteratorCharStream(new CharIteratorEx() {
private char nextA = 0;
private char nextB = 0;
private boolean hasNextA = false;
private boolean hasNextB = false;
@Override
public boolean hasNext() {
return a.hasNext() || b.hasNext() || hasNextA || hasNextB;
}
@Override
public char nextChar() {
if (hasNextA) {
if (b.hasNext()) {
if (nextSelector.apply(nextA, (nextB = b.nextChar())) == Nth.FIRST) {
hasNextA = false;
hasNextB = true;
return nextA;
} else {
return nextB;
}
} else {
hasNextA = false;
return nextA;
}
} else if (hasNextB) {
if (a.hasNext()) {
if (nextSelector.apply((nextA = a.nextChar()), nextB) == Nth.FIRST) {
return nextA;
} else {
hasNextA = true;
hasNextB = false;
return nextB;
}
} else {
hasNextB = false;
return nextB;
}
} else if (a.hasNext()) {
if (b.hasNext()) {
if (nextSelector.apply((nextA = a.nextChar()), (nextB = b.nextChar())) == Nth.FIRST) {
hasNextB = true;
return nextA;
} else {
hasNextA = true;
return nextB;
}
} else {
return a.nextChar();
}
} else if (b.hasNext()) {
return b.nextChar();
} else {
throw new NoSuchElementException();
}
}
});
}
/**
*
* @param a
* @param b
* @param c
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream merge(final CharIterator a, final CharIterator b, final CharIterator c, final CharBiFunction nextSelector) {
return merge(merge(a, b, nextSelector).iteratorEx(), c, nextSelector);
}
/**
*
* @param a
* @param b
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream merge(final CharStream a, final CharStream b, final CharBiFunction nextSelector) {
return merge(a.iteratorEx(), b.iteratorEx(), nextSelector).onClose(newCloseHandler(N.asList(a, b)));
}
/**
*
* @param a
* @param b
* @param c
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream merge(final CharStream a, final CharStream b, final CharStream c, final CharBiFunction nextSelector) {
return merge(merge(a, b, nextSelector), c, nextSelector);
}
/**
*
* @param c
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream merge(final Collection c, final CharBiFunction nextSelector) {
if (N.isNullOrEmpty(c)) {
return empty();
} else if (c.size() == 1) {
return c.iterator().next();
} else if (c.size() == 2) {
final Iterator iter = c.iterator();
return merge(iter.next(), iter.next(), nextSelector);
}
final Iterator iter = c.iterator();
CharStream result = merge(iter.next(), iter.next(), nextSelector);
while (iter.hasNext()) {
result = merge(result, iter.next(), nextSelector);
}
return result;
}
/**
*
* @param c
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @return
*/
public static CharStream parallelMerge(final Collection c, final CharBiFunction nextSelector) {
return parallelMerge(c, nextSelector, DEFAULT_MAX_THREAD_NUM);
}
/**
*
* @param c
* @param nextSelector first parameter is selected if Nth.FIRST is returned, otherwise the second parameter is selected.
* @param maxThreadNum
* @return
*/
public static CharStream parallelMerge(final Collection c, final CharBiFunction nextSelector, final int maxThreadNum) {
N.checkArgument(maxThreadNum > 0, "'maxThreadNum' must not less than 1");
if (maxThreadNum <= 1) {
return merge(c, nextSelector);
} else if (N.isNullOrEmpty(c)) {
return empty();
} else if (c.size() == 1) {
return c.iterator().next();
} else if (c.size() == 2) {
final Iterator iter = c.iterator();
return merge(iter.next(), iter.next(), nextSelector);
} else if (c.size() == 3) {
final Iterator iter = c.iterator();
return merge(iter.next(), iter.next(), iter.next(), nextSelector);
}
final Queue queue = N.newLinkedList();
for (CharStream e : c) {
queue.add(e);
}
final Holder eHolder = new Holder<>();
final MutableInt cnt = MutableInt.of(c.size());
final List> futureList = new ArrayList<>(c.size() - 1);
for (int i = 0, n = N.min(maxThreadNum, c.size() / 2 + 1); i < n; i++) {
futureList.add(DEFAULT_ASYNC_EXECUTOR.execute(new Try.Runnable() {
@Override
public void run() {
CharStream a = null;
CharStream b = null;
CharStream c = null;
try {
while (eHolder.value() == null) {
synchronized (queue) {
if (cnt.intValue() > 2 && queue.size() > 1) {
a = queue.poll();
b = queue.poll();
cnt.decrement();
} else {
break;
}
}
c = CharStream.of(merge(a, b, nextSelector).toArray());
synchronized (queue) {
queue.offer(c);
}
}
} catch (Exception e) {
setError(eHolder, e);
}
}
}));
}
try {
complete(futureList, eHolder);
} finally {
if (eHolder.value() != null) {
IOUtil.closeAllQuietly(c);
}
}
return merge(queue.poll(), queue.poll(), nextSelector);
}
}