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package com.annimon.stream;
import com.annimon.stream.function.*;
import java.util.Arrays;
import java.util.Comparator;
import java.util.NoSuchElementException;
/**
* A sequence of primitive int-valued elements supporting sequential operations. This is the {@code int}
* primitive specialization of {@link Stream}.
*/
@SuppressWarnings("WeakerAccess")
public final class IntStream {
/**
* Single instance for empty stream. It is safe for multi-thread environment because it has no content.
*/
private static final IntStream EMPTY = new IntStream(new PrimitiveIterator.OfInt() {
@Override
public int nextInt() {
return 0;
}
@Override
public boolean hasNext() {
return false;
}
});
/**
* Returns an empty stream.
*
* @return the empty stream
*/
public static IntStream empty() {
return EMPTY;
}
/**
* Creates a {@code IntStream} from {@code PrimitiveIterator.OfInt}.
*
* @param iterator the iterator with elements to be passed to stream
* @return the new {@code IntStream}
* @throws NullPointerException if {@code iterator} is null
*/
public static IntStream of(PrimitiveIterator.OfInt iterator) {
Objects.requireNonNull(iterator);
return new IntStream(iterator);
}
/**
* Returns stream whose elements are the specified values.
*
* @param values the elements of the new stream
* @return the new stream
* @throws NullPointerException if {@code values} is null
*/
public static IntStream of(final int... values) {
Objects.requireNonNull(values);
return new IntStream(new PrimitiveIterator.OfInt() {
private int index = 0;
@Override
public int nextInt() {
return values[index++];
}
@Override
public boolean hasNext() {
return index < values.length;
}
});
}
/**
* Returns stream which contains single element passed as param
*
* @param t element of the stream
* @return the new stream
*/
public static IntStream of(final int t) {
return new IntStream(new PrimitiveIterator.OfInt() {
private int index = 0;
@Override
public int nextInt() {
index++;
return t;
}
@Override
public boolean hasNext() {
return index == 0;
}
});
}
/**
* Returns a sequential ordered {@code IntStream} from {@code startInclusive}
* (inclusive) to {@code endExclusive} (exclusive) by an incremental step of
* {@code 1}.
*
* @param startInclusive the (inclusive) initial value
* @param endExclusive the exclusive upper bound
* @return a sequential {@code IntStream} for the range of {@code int}
* elements
*/
public static IntStream range(final int startInclusive, final int endExclusive) {
if (startInclusive >= endExclusive) {
return empty();
}
return rangeClosed(startInclusive, endExclusive - 1);
}
/**
* Returns a sequential ordered {@code IntStream} from {@code startInclusive}
* (inclusive) to {@code endInclusive} (inclusive) by an incremental step of
* {@code 1}.
*
* @param startInclusive the (inclusive) initial value
* @param endInclusive the inclusive upper bound
* @return a sequential {@code IntStream} for the range of {@code int}
* elements
*/
public static IntStream rangeClosed(final int startInclusive, final int endInclusive) {
if (startInclusive > endInclusive) {
return empty();
} else if (startInclusive == endInclusive) {
return of(startInclusive);
} else return new IntStream(new PrimitiveIterator.OfInt() {
private int current = startInclusive;
private boolean hasNext = current <= endInclusive;
@Override
public boolean hasNext() {
return hasNext;
}
@Override
public int nextInt() {
if (current >= endInclusive) {
hasNext = false;
return endInclusive;
}
return current++;
}
});
}
/**
* Returns an infinite sequential unordered stream where each element is
* generated by the provided {@code IntSupplier}. This is suitable for
* generating constant streams, streams of random elements, etc.
*
* @param s the {@code IntSupplier} for generated elements
* @return a new infinite sequential {@code IntStream}
* @throws NullPointerException if {@code s} is null
*/
public static IntStream generate(final IntSupplier s) {
Objects.requireNonNull(s);
return new IntStream(new PrimitiveIterator.OfInt() {
@Override
public int nextInt() {
return s.getAsInt();
}
@Override
public boolean hasNext() {
return true;
}
});
}
/**
* Returns an infinite sequential ordered {@code IntStream} produced by iterative
* application of a function {@code f} to an initial element {@code seed},
* producing a {@code Stream} consisting of {@code seed}, {@code f(seed)},
* {@code f(f(seed))}, etc.
*
* The first element (position {@code 0}) in the {@code IntStream} will be
* the provided {@code seed}. For {@code n > 0}, the element at position
* {@code n}, will be the result of applying the function {@code f} to the
* element at position {@code n - 1}.
*
*
Example:
*
* seed: 1
* f: (a) -> a + 5
* result: [1, 6, 11, 16, ...]
*
*
* @param seed the initial element
* @param f a function to be applied to the previous element to produce
* a new element
* @return a new sequential {@code IntStream}
* @throws NullPointerException if {@code f} is null
*/
public static IntStream iterate(final int seed, final IntUnaryOperator f) {
Objects.requireNonNull(f);
return new IntStream(new PrimitiveIterator.OfInt() {
private int current = seed;
@Override
public int nextInt() {
int old = current;
current = f.applyAsInt(current);
return old;
}
@Override
public boolean hasNext() {
return true;
}
});
}
/**
* Creates an {@code IntStream} by iterative application {@code IntUnaryOperator} function
* to an initial element {@code seed}, conditioned on satisfying the supplied predicate.
*
* Example:
*
* seed: 0
* predicate: (a) -> a < 20
* f: (a) -> a + 5
* result: [0, 5, 10, 15]
*
*
* @param seed the initial value
* @param predicate a predicate to determine when the stream must terminate
* @param op operator to produce new element by previous one
* @return the new stream
* @throws NullPointerException if {@code op} is null
* @since 1.1.5
*/
public static IntStream iterate(final int seed,
final IntPredicate predicate, final IntUnaryOperator op) {
Objects.requireNonNull(predicate);
return iterate(seed, op).takeWhile(predicate);
}
/**
* Creates a lazily concatenated stream whose elements are all the
* elements of the first stream followed by all the elements of the
* second stream.
*
* Example:
*
* stream a: [1, 2, 3, 4]
* stream b: [5, 6]
* result: [1, 2, 3, 4, 5, 6]
*
*
* @param a the first stream
* @param b the second stream
* @return the concatenation of the two input streams
* @throws NullPointerException if {@code a} or {@code b} is null
*/
public static IntStream concat(final IntStream a, final IntStream b) {
Objects.requireNonNull(a);
Objects.requireNonNull(b);
return new IntStream(new PrimitiveIterator.OfInt() {
private boolean firstStreamIsCurrent = true;
@Override
public int nextInt() {
return firstStreamIsCurrent ? a.iterator.nextInt() : b.iterator.nextInt();
}
@Override
public boolean hasNext() {
if(firstStreamIsCurrent) {
if(a.iterator.hasNext())
return true;
firstStreamIsCurrent = false;
}
return b.iterator.hasNext();
}
});
}
private final PrimitiveIterator.OfInt iterator;
private IntStream(PrimitiveIterator.OfInt iterator) {
this.iterator = iterator;
}
/**
* Returns internal {@code IntStream} iterator.
*
* @return internal {@code IntStream} iterator.
*/
public PrimitiveIterator.OfInt iterator() {
return iterator;
}
/**
* Applies custom operator on stream.
*
* Transforming function can return {@code IntStream} for intermediate operations,
* or any value for terminal operation.
*
* Operator examples:
*
* // Intermediate operator
* public class Zip<T> implements Function<IntStream, IntStream> {
* @Override
* public IntStream apply(IntStream firstStream) {
* final PrimitiveIterator.OfInt it1 = firstStream.iterator();
* final PrimitiveIterator.OfInt it2 = secondStream.iterator();
* return IntStream.of(new PrimitiveIterator.OfInt() {
* @Override
* public boolean hasNext() {
* return it1.hasNext() && it2.hasNext();
* }
*
* @Override
* public int nextInt() {
* return combiner.applyAsInt(it1.nextInt(), it2.nextInt());
* }
* });
* }
* }
*
* // Intermediate operator based on existing stream operators
* public class SkipAndLimit implements UnaryOperator<IntStream> {
*
* private final int skip, limit;
*
* public SkipAndLimit(int skip, int limit) {
* this.skip = skip;
* this.limit = limit;
* }
*
* @Override
* public IntStream apply(IntStream stream) {
* return stream.skip(skip).limit(limit);
* }
* }
*
* // Terminal operator
* public class Average implements Function<IntStream, Double> {
* long count = 0, sum = 0;
*
* @Override
* public Double apply(IntStream stream) {
* final PrimitiveIterator.OfInt it = stream.iterator();
* while (it.hasNext()) {
* count++;
* sum += it.nextInt();
* }
* return (count == 0) ? 0 : sum / (double) count;
* }
* }
*
*
* @param the type of the result
* @param function a transforming function
* @return a result of the transforming function
* @see Stream#custom(com.annimon.stream.function.Function)
* @throws NullPointerException if {@code function} is null
*/
public R custom(final Function function) {
Objects.requireNonNull(function);
return function.apply(this);
}
/**
* Returns a {@code Stream} consisting of the elements of this stream,
* each boxed to an {@code Integer}.
*
* This is an lazy intermediate operation.
*
* @return a {@code Stream} consistent of the elements of this stream,
* each boxed to an {@code Integer}
*/
public Stream boxed() {
return Stream.of(iterator);
}
/**
* Returns a stream consisting of the elements of this stream that match
* the given predicate.
*
* This is an intermediate operation.
*
*
Example:
*
* predicate: (a) -> a > 2
* stream: [1, 2, 3, 4, -8, 0, 11]
* result: [3, 4, 11]
*
*
* @param predicate non-interfering, stateless predicate to apply to each
* element to determine if it should be included
* @return the new stream
*/
public IntStream filter(final IntPredicate predicate) {
return new IntStream(new PrimitiveIterator.OfInt() {
private int next;
@Override
public int nextInt() {
return next;
}
@Override
public boolean hasNext() {
while(iterator.hasNext()) {
next = iterator.next();
if(predicate.test(next)) {
return true;
}
}
return false;
}
});
}
/**
* Returns a stream consisting of the elements of this stream that don't
* match the given predicate.
*
* This is an intermediate operation.
*
* @param predicate non-interfering, stateless predicate to apply to each
* element to determine if it should not be included
* @return the new stream
*/
public IntStream filterNot(final IntPredicate predicate) {
return filter(IntPredicate.Util.negate(predicate));
}
/**
* Returns an {@code IntStream} consisting of the results of applying the given
* function to the elements of this stream.
*
*
This is an intermediate operation.
*
*
Example:
*
* mapper: (a) -> a + 5
* stream: [1, 2, 3, 4]
* result: [6, 7, 8, 9]
*
*
* @param mapper a non-interfering stateless function to apply to
* each element
* @return the new {@code IntStream}
*/
public IntStream map(final IntUnaryOperator mapper) {
return new IntStream(new PrimitiveIterator.OfInt() {
@Override
public int nextInt() {
return mapper.applyAsInt(iterator.nextInt());
}
@Override
public boolean hasNext() {
return iterator.hasNext();
}
});
}
/**
* Returns a {@code Stream} consisting of the results of applying the given
* function to the elements of this stream.
*
* This is an intermediate operation.
*
* @param the type result
* @param mapper the mapper function used to apply to each element
* @return the new {@code Stream}
*/
public Stream mapToObj(final IntFunction mapper) {
return Stream.of(new LsaIterator() {
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public R nextIteration() {
return mapper.apply(iterator.nextInt());
}
});
}
/**
* Returns a {@code LongStream} consisting of the results of applying the given
* function to the elements of this stream.
*
* This is an intermediate operation.
*
* @param mapper the mapper function used to apply to each element
* @return the new {@code LongStream}
* @since 1.1.4
* @see #flatMap(com.annimon.stream.function.IntFunction)
*/
public LongStream mapToLong(final IntToLongFunction mapper) {
return LongStream.of(new PrimitiveIterator.OfLong() {
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public long nextLong() {
return mapper.applyAsLong(iterator.nextInt());
}
});
}
/**
* Returns a {@code DoubleStream} consisting of the results of applying the given
* function to the elements of this stream.
*
*
This is an intermediate operation.
*
* @param mapper the mapper function used to apply to each element
* @return the new {@code DoubleStream}
* @since 1.1.4
* @see #flatMap(com.annimon.stream.function.IntFunction)
*/
public DoubleStream mapToDouble(final IntToDoubleFunction mapper) {
return DoubleStream.of(new PrimitiveIterator.OfDouble() {
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public double nextDouble() {
return mapper.applyAsDouble(iterator.nextInt());
}
});
}
/**
* 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.
*
*
Example:
*
* mapper: (a) -> [a, a + 5]
* stream: [1, 2, 3, 4]
* result: [1, 6, 2, 7, 3, 8, 4, 9]
*
*
* @param mapper a non-interfering stateless function to apply to each
* element which produces an {@code IntStream} of new values
* @return the new stream
* @see Stream#flatMap(Function)
*/
public IntStream flatMap(final IntFunction mapper) {
return new IntStream(new PrimitiveIterator.OfInt() {
private PrimitiveIterator.OfInt inner;
@Override
public int nextInt() {
if (inner == null) {
throw new NoSuchElementException();
}
return inner.nextInt();
}
@Override
public boolean hasNext() {
if (inner != null && inner.hasNext()) {
return true;
}
while (iterator.hasNext()) {
final int arg = iterator.next();
final IntStream result = mapper.apply(arg);
if (result == null) {
continue;
}
if (result.iterator.hasNext()) {
inner = result.iterator;
return true;
}
}
return false;
}
});
}
/**
* Returns a stream consisting of the distinct elements of this stream.
*
* This is a stateful intermediate operation.
*
*
Example:
*
* stream: [1, 4, 2, 3, 3, 4, 1]
* result: [1, 4, 2, 3]
*
*
* @return the new stream
*/
public IntStream distinct() {
// While functional and quick to implement, this approach is not very efficient.
// An efficient version requires an int-specific map/set implementation.
return boxed().distinct().mapToInt(UNBOX_FUNCTION);
}
/**
* Returns a stream consisting of the elements of this stream in sorted
* order.
*
* This is a stateful intermediate operation.
*
*
Example:
*
* stream: [3, 4, 1, 2]
* result: [1, 2, 3, 4]
*
*
* @return the new stream
*/
public IntStream sorted() {
return new IntStream(new PrimitiveExtIterator.OfInt() {
private int index = 0;
private int[] array;
@Override
protected void nextIteration() {
if (!isInit) {
array = toArray();
Arrays.sort(array);
}
hasNext = index < array.length;
if (hasNext) {
next = array[index++];
}
}
});
}
/**
* Returns {@code IntStream} with sorted elements (as determinated by provided {@code Comparator}).
*
* This is a stateful intermediate operation.
*
*
Example:
*
* comparator: (a, b) -> -a.compareTo(b)
* stream: [1, 2, 3, 4]
* result: [4, 3, 2, 1]
*
*
* @param comparator the {@code Comparator} to compare elements
* @return the new {@code IntStream}
*/
public IntStream sorted(Comparator comparator) {
return boxed().sorted(comparator).mapToInt(UNBOX_FUNCTION);
}
/**
* Samples the {@code IntStream} by emitting every n-th element.
*
* This is an intermediate operation.
*
*
Example:
*
* stepWidth: 3
* stream: [1, 2, 3, 4, 5, 6, 7, 8]
* result: [1, 4, 7]
*
*
* @param stepWidth step width
* @return the new {@code IntStream}
* @throws IllegalArgumentException if {@code stepWidth} is zero or negative
* @see Stream#sample(int)
*/
public IntStream sample(final int stepWidth) {
if (stepWidth <= 0) throw new IllegalArgumentException("stepWidth cannot be zero or negative");
if (stepWidth == 1) return this;
return new IntStream(new PrimitiveIterator.OfInt() {
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public int nextInt() {
final int result = iterator.nextInt();
int skip = 1;
while (skip < stepWidth && iterator.hasNext()) {
iterator.nextInt();
skip++;
}
return result;
}
});
}
/**
* Returns a stream consisting of the elements of this stream, additionally
* performing the provided action on each element as elements are consumed
* from the resulting stream. Handy method for debugging purposes.
*
* This is an intermediate operation.
*
* @param action the action to be performed on each element
* @return the new stream
*/
public IntStream peek(final IntConsumer action) {
return new IntStream(new PrimitiveIterator.OfInt() {
@Override
public int nextInt() {
int value = iterator.nextInt();
action.accept(value);
return value;
}
@Override
public boolean hasNext() {
return iterator.hasNext();
}
});
}
/**
* Takes elements while the predicate is true.
*
*
This is an intermediate operation.
*
*
Example:
*
* predicate: (a) -> a < 3
* stream: [1, 2, 3, 4, 1, 2, 3, 4]
* result: [1, 2]
*
*
* @param predicate the predicate used to take elements
* @return the new {@code IntStream}
*/
public IntStream takeWhile(final IntPredicate predicate) {
return new IntStream(new PrimitiveExtIterator.OfInt() {
@Override
protected void nextIteration() {
hasNext = iterator.hasNext() && predicate.test(next = iterator.next());
}
});
}
/**
* Drops elements while the predicate is true and returns the rest.
*
* This is an intermediate operation.
*
*
Example:
*
* predicate: (a) -> a < 3
* stream: [1, 2, 3, 4, 1, 2, 3, 4]
* result: [3, 4, 1, 2, 3, 4]
*
*
* @param predicate the predicate used to drop elements
* @return the new {@code IntStream}
*/
public IntStream dropWhile(final IntPredicate predicate) {
return new IntStream(new PrimitiveExtIterator.OfInt() {
@Override
protected void nextIteration() {
if (!isInit) {
// Skip first time
while (hasNext = iterator.hasNext()) {
next = iterator.next();
if (!predicate.test(next)) {
return;
}
}
}
hasNext = hasNext && iterator.hasNext();
if (!hasNext) return;
next = iterator.next();
}
});
}
/**
* Returns a stream consisting of the elements of this stream, truncated
* to be no longer than {@code maxSize} in length.
*
* This is a short-circuiting stateful intermediate operation.
*
*
Example:
*
* maxSize: 3
* stream: [1, 2, 3, 4, 5]
* result: [1, 2, 3]
*
* maxSize: 10
* stream: [1, 2]
* result: [1, 2]
*
*
* @param maxSize the number of elements the stream should be limited to
* @return the new stream
* @throws IllegalArgumentException if {@code maxSize} is negative
*/
public IntStream limit(final long maxSize) {
if (maxSize < 0) {
throw new IllegalArgumentException("maxSize cannot be negative");
}
if (maxSize == 0) {
return IntStream.empty();
}
return new IntStream(new PrimitiveIterator.OfInt() {
private long index = 0;
@Override
public int nextInt() {
index++;
return iterator.nextInt();
}
@Override
public boolean hasNext() {
return (index < maxSize) && iterator.hasNext();
}
});
}
/**
* Returns a stream consisting of the remaining elements of this stream
* after discarding the first {@code n} elements of the stream.
* If this stream contains fewer than {@code n} elements then an
* empty stream will be returned.
*
* This is a stateful intermediate operation.
*
*
Example:
*
* n: 3
* stream: [1, 2, 3, 4, 5]
* result: [4, 5]
*
* n: 10
* stream: [1, 2]
* result: []
*
*
* @param n the number of leading elements to skip
* @return the new stream
* @throws IllegalArgumentException if {@code n} is negative
*/
public IntStream skip(final long n) {
if(n < 0)
throw new IllegalArgumentException("n cannot be negative");
if(n == 0)
return this;
else
return new IntStream(new PrimitiveIterator.OfInt() {
long skipped = 0;
@Override
public int nextInt() {
return iterator.nextInt();
}
@Override
public boolean hasNext() {
while(iterator.hasNext()) {
if(skipped == n) break;
skipped++;
iterator.nextInt();
}
return iterator.hasNext();
}
});
}
/**
* Performs an action for each element of this stream.
*
* This is a terminal operation.
*
* @param action a non-interfering action to perform on the elements
*/
public void forEach(IntConsumer action) {
while(iterator.hasNext()) {
action.accept(iterator.nextInt());
}
}
/**
* Performs a reduction on the elements of this stream, using the provided
* identity value and an associative accumulation function, and returns the
* reduced value.
*
*
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.
*
*
Example:
*
* identity: 0
* accumulator: (a, b) -> a + b
* stream: [1, 2, 3, 4, 5]
* result: 15
*
*
* @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()
*/
public int reduce(int identity, IntBinaryOperator op) {
int result = identity;
while(iterator.hasNext()) {
int value = iterator.nextInt();
result = op.applyAsInt(result, value);
}
return result;
}
/**
* Performs a reduction on the elements of this stream, using an
* associative accumulation function, and returns an {@code OptionalInt}
* describing the reduced value, if any.
*
* The {@code op} 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, IntBinaryOperator)
*/
public OptionalInt reduce(IntBinaryOperator op) {
boolean foundAny = false;
int result = 0;
while(iterator.hasNext()) {
int value = iterator.nextInt();
if(!foundAny) {
foundAny = true;
result = value;
} else {
result = op.applyAsInt(result, value);
}
}
return foundAny ? OptionalInt.of(result) : OptionalInt.empty();
}
/**
* Returns an array containing the elements of this stream.
*
*
This is a terminal operation.
*
* @return an array containing the elements of this stream
*/
public int[] toArray() {
SpinedBuffer.OfInt b = new SpinedBuffer.OfInt();
forEach(b);
return b.asPrimitiveArray();
}
/**
* Collects elements to {@code supplier} provided container by applying the given accumulation function.
*
*
This is a terminal operation.
*
* @param the type of the result
* @param supplier the supplier function that provides container
* @param accumulator the accumulation function
* @return the result of collect elements
* @see Stream#collect(com.annimon.stream.function.Supplier, com.annimon.stream.function.BiConsumer)
*/
public R collect(Supplier supplier, ObjIntConsumer accumulator) {
R result = supplier.get();
while (iterator.hasNext()) {
final int value = iterator.nextInt();
accumulator.accept(result, value);
}
return result;
}
/**
* Returns the sum of elements in this stream.
*
* @return the sum of elements in this stream
*/
public int sum() {
int sum = 0;
while(iterator.hasNext()) {
sum += iterator.nextInt();
}
return sum;
}
/**
* Returns an {@code OptionalInt} describing the minimum element of this
* stream, or an empty optional if this stream is empty.
*
* This is a terminal operation.
*
* @return an {@code OptionalInt} containing the minimum element of this
* stream, or an empty {@code OptionalInt} if the stream is empty
*/
public OptionalInt min() {
return reduce(new IntBinaryOperator() {
@Override
public int applyAsInt(int left, int right) {
return left < right ? left : right;
}
});
}
/**
* Returns an {@code OptionalInt} describing the maximum element of this
* stream, or an empty optional if this stream is empty.
*
*
This is a terminal operation.
*
* @return an {@code OptionalInt} containing the maximum element of this
* stream, or an empty {@code OptionalInt} if the stream is empty
*/
public OptionalInt max() {
return reduce(new IntBinaryOperator() {
@Override
public int applyAsInt(int left, int right) {
return left > right ? left : right;
}
});
}
/**
* Returns the count of elements in this stream.
*
*
This is a terminal operation.
*
* @return the count of elements in this stream
*/
public long count() {
long count = 0;
while(iterator.hasNext()) {
iterator.nextInt();
count++;
}
return count;
}
/**
* Returns whether any elements of this stream match the provided
* predicate. May not evaluate the predicate on all elements if not
* necessary for determining the result. If the stream is empty then
* {@code false} is returned and the predicate is not evaluated.
*
*
This is a short-circuiting terminal operation.
*
*
Example:
*
* predicate: (a) -> a == 5
* stream: [1, 2, 3, 4, 5]
* result: true
*
* predicate: (a) -> a == 5
* stream: [5, 5, 5]
* result: true
*
*
* @param predicate a non-interfering stateless predicate to apply
* to elements of this stream
* @return {@code true} if any elements of the stream match the provided
* predicate, otherwise {@code false}
*/
public boolean anyMatch(IntPredicate predicate) {
while(iterator.hasNext()) {
if(predicate.test(iterator.nextInt()))
return true;
}
return false;
}
/**
* Returns whether all elements of this stream match the provided predicate.
* May not evaluate the predicate on all elements if not necessary for
* determining the result. If the stream is empty then {@code true} is
* returned and the predicate is not evaluated.
*
* This is a short-circuiting terminal operation.
*
*
Example:
*
* predicate: (a) -> a == 5
* stream: [1, 2, 3, 4, 5]
* result: false
*
* predicate: (a) -> a == 5
* stream: [5, 5, 5]
* result: true
*
*
* @param predicate a non-interfering stateless predicate to apply to
* elements of this stream
* @return {@code true} if either all elements of the stream match the
* provided predicate or the stream is empty, otherwise {@code false}
*/
public boolean allMatch(IntPredicate predicate) {
while(iterator.hasNext()) {
if(!predicate.test(iterator.nextInt()))
return false;
}
return true;
}
/**
* Returns whether no elements of this stream match the provided predicate.
* May not evaluate the predicate on all elements if not necessary for
* determining the result. If the stream is empty then {@code true} is
* returned and the predicate is not evaluated.
*
* This is a short-circuiting terminal operation.
*
*
Example:
*
* predicate: (a) -> a == 5
* stream: [1, 2, 3, 4, 5]
* result: false
*
* predicate: (a) -> a == 5
* stream: [1, 2, 3]
* result: true
*
*
* @param predicate a non-interfering stateless predicate to apply to
* elements of this stream
* @return {@code true} if either no elements of the stream match the
* provided predicate or the stream is empty, otherwise {@code false}
*/
public boolean noneMatch(IntPredicate predicate) {
while (iterator.hasNext()) {
if (predicate.test(iterator.nextInt()))
return false;
}
return true;
}
/**
* Returns an {@link OptionalInt} describing the first element of this
* stream, or an empty {@code OptionalInt} if the stream is empty.
*
* This is a short-circuiting terminal operation.
*
* @return an {@code OptionalInt} describing the first element of this stream,
* or an empty {@code OptionalInt} if the stream is empty
*/
public OptionalInt findFirst() {
if(iterator.hasNext()) {
return OptionalInt.of(iterator.nextInt());
} else {
return OptionalInt.empty();
}
}
/**
* Returns the single element of stream.
* If stream is empty, throws {@code NoSuchElementException}.
* If stream contains more than one element, throws {@code IllegalStateException}.
*
*
This is a short-circuiting terminal operation.
*
*
Example:
*
* stream: []
* result: NoSuchElementException
*
* stream: [1]
* result: 1
*
* stream: [1, 2, 3]
* result: IllegalStateException
*
*
* @return single element of stream
* @throws NoSuchElementException if stream is empty
* @throws IllegalStateException if stream contains more than one element
* @since 1.1.3
*/
public int single() {
if (iterator.hasNext()) {
int singleCandidate = iterator.next();
if (iterator.hasNext()) {
throw new IllegalStateException("IntStream contains more than one element");
} else {
return singleCandidate;
}
} else {
throw new NoSuchElementException("IntStream contains no element");
}
}
/**
* Returns the single element wrapped by {@code OptionalInt} class.
* If stream is empty, returns {@code OptionalInt.empty()}.
* If stream contains more than one element, throws {@code IllegalStateException}.
*
* This is a short-circuiting terminal operation.
*
*
Example:
*
* stream: []
* result: OptionalInt.empty()
*
* stream: [1]
* result: OptionalInt.of(1)
*
* stream: [1, 2, 3]
* result: IllegalStateException
*
*
* @return an {@code OptionalInt} with single element or {@code OptionalInt.empty()} if stream is empty
* @throws IllegalStateException if stream contains more than one element
* @since 1.1.3
*/
public OptionalInt findSingle() {
if (iterator.hasNext()) {
int singleCandidate = iterator.next();
if (iterator.hasNext()) {
throw new IllegalStateException("IntStream contains more than one element");
} else {
return OptionalInt.of(singleCandidate);
}
} else {
return OptionalInt.empty();
}
}
private static final ToIntFunction UNBOX_FUNCTION = new ToIntFunction() {
@Override
public int applyAsInt(Integer t) {
return t;
}
};
}