com.annimon.stream.LongStream Maven / Gradle / Ivy
package com.annimon.stream;
import java.io.Closeable;
import java.math.BigInteger;
import java.util.Comparator;
import java.util.NoSuchElementException;
import com.annimon.stream.internal.Compose;
import com.annimon.stream.internal.Operators;
import com.annimon.stream.internal.Params;
import com.annimon.stream.iterator.PrimitiveIterator;
import com.annimon.stream.iterator.PrimitiveIterator.OfLong;
import com.annimon.stream.operator.LongArray;
import com.annimon.stream.operator.LongConcat;
import com.annimon.stream.operator.LongDropWhile;
import com.annimon.stream.operator.LongFilter;
import com.annimon.stream.operator.LongFlatMap;
import com.annimon.stream.operator.LongGenerate;
import com.annimon.stream.operator.LongIterate;
import com.annimon.stream.operator.LongLimit;
import com.annimon.stream.operator.LongMap;
import com.annimon.stream.operator.LongMapToDouble;
import com.annimon.stream.operator.LongMapToInt;
import com.annimon.stream.operator.LongMapToObj;
import com.annimon.stream.operator.LongPeek;
import com.annimon.stream.operator.LongRangeClosed;
import com.annimon.stream.operator.LongScan;
import com.annimon.stream.operator.LongScanIdentity;
import com.annimon.stream.operator.LongSkip;
import com.annimon.stream.operator.LongSorted;
import com.annimon.stream.operator.LongTakeUntil;
import com.annimon.stream.operator.LongTakeWhile;
import com.landawn.abacus.util.N;
import com.landawn.abacus.util.OptionalDouble;
import com.landawn.abacus.util.OptionalLong;
import com.landawn.abacus.util.function.Function;
import com.landawn.abacus.util.function.LongBinaryOperator;
import com.landawn.abacus.util.function.LongConsumer;
import com.landawn.abacus.util.function.LongFunction;
import com.landawn.abacus.util.function.LongPredicate;
import com.landawn.abacus.util.function.LongSupplier;
import com.landawn.abacus.util.function.LongToDoubleFunction;
import com.landawn.abacus.util.function.LongToIntFunction;
import com.landawn.abacus.util.function.LongUnaryOperator;
import com.landawn.abacus.util.function.ObjLongConsumer;
import com.landawn.abacus.util.function.Supplier;
import com.landawn.abacus.util.function.ToLongFunction;
/**
* A sequence of {@code long}-valued elements supporting aggregate operations.
*
* @since 1.1.4
* @see Stream
*/
public final class LongStream implements Closeable {
/**
* Single instance for empty stream. It is safe for multi-thread environment because it has no content.
*/
private static final LongStream EMPTY = new LongStream(new PrimitiveIterator.OfLong() {
@Override
public boolean hasNext() {
return false;
}
@Override
public long nextLong() {
return 0L;
}
});
/**
* Returns an empty stream.
*
* @return the empty stream
*/
public static LongStream empty() {
return EMPTY;
}
/**
* Creates a {@code LongStream} from the specified values.
*
* @param values the elements of the new stream
* @return the new stream
* @throws NullPointerException if {@code values} is null
*/
public static LongStream of(final long... values) {
if (values == null || values.length == 0) {
return LongStream.empty();
}
return new LongStream(new LongArray(values));
}
/**
* Creates a {@code LongStream} from {@code PrimitiveIterator.OfLong}.
*
* @param iterator the iterator with elements to be passed to stream
* @return the new {@code LongStream}
* @throws NullPointerException if {@code iterator} is null
*/
public static LongStream of(PrimitiveIterator.OfLong iterator) {
N.requireNonNull(iterator);
return new LongStream(iterator);
}
/**
* Returns a sequential ordered {@code LongStream} 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 LongStream} for the range of {@code long}
* elements
*/
public static LongStream range(final long startInclusive, final long endExclusive) {
if (startInclusive >= endExclusive) {
return empty();
}
return rangeClosed(startInclusive, endExclusive - 1);
}
public static LongStream range(final long startInclusive, final long endExclusive, final long by) {
if (by == 0) {
throw new IllegalArgumentException("'by' can't be zero");
}
if (endExclusive == startInclusive || endExclusive > startInclusive != by > 0) {
return empty();
}
if ((by > 0 && endExclusive - startInclusive < 0) || (by < 0 && startInclusive - endExclusive < 0)) {
long m = BigInteger.valueOf(endExclusive).subtract(BigInteger.valueOf(startInclusive)).divide(BigInteger.valueOf(3)).longValue();
if ((by > 0 && by > m) || (by < 0 && by < m)) {
return concat(range(startInclusive, startInclusive + by), range(startInclusive + by, endExclusive));
} else {
m = m > 0 ? m - m % by : m + m % by;
return concat(concat(range(startInclusive, startInclusive + m, by), range(startInclusive + m, (startInclusive + m) + m, by)),
range((startInclusive + m) + m, endExclusive, by));
}
}
return of(new PrimitiveIterator.OfLong() {
private long next = startInclusive;
private long cnt = (endExclusive - startInclusive) / by + ((endExclusive - startInclusive) % by == 0 ? 0 : 1);
@Override
public boolean hasNext() {
return cnt > 0;
}
@Override
public long nextLong() {
if (cnt-- <= 0) {
throw new NoSuchElementException();
}
long result = next;
next += by;
return result;
}
});
}
/**
* Returns a sequential ordered {@code LongStream} 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 LongStream} for the range of {@code long}
* elements
*/
public static LongStream rangeClosed(final long startInclusive, final long endInclusive) {
if (startInclusive > endInclusive) {
return empty();
} else if (startInclusive == endInclusive) {
return of(startInclusive);
} else
return new LongStream(new LongRangeClosed(startInclusive, endInclusive));
}
public static LongStream rangeClosed(final long startInclusive, final long endInclusive, final long 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();
}
if ((by > 0 && endInclusive - startInclusive < 0) || (by < 0 && startInclusive - endInclusive < 0) || ((endInclusive - startInclusive) / by + 1 <= 0)) {
long m = BigInteger.valueOf(endInclusive).subtract(BigInteger.valueOf(startInclusive)).divide(BigInteger.valueOf(3)).longValue();
if ((by > 0 && by > m) || (by < 0 && by < m)) {
return concat(range(startInclusive, startInclusive + by), rangeClosed(startInclusive + by, endInclusive));
} else {
m = m > 0 ? m - m % by : m + m % by;
return concat(concat(range(startInclusive, startInclusive + m, by), range(startInclusive + m, (startInclusive + m) + m, by)),
rangeClosed((startInclusive + m) + m, endInclusive, by));
}
}
return of(new PrimitiveIterator.OfLong() {
private long next = startInclusive;
private long cnt = (endInclusive - startInclusive) / by + 1;
@Override
public boolean hasNext() {
return cnt > 0;
}
@Override
public long nextLong() {
if (cnt-- <= 0) {
throw new NoSuchElementException();
}
long result = next;
next += by;
return result;
}
});
}
/**
* Creates a {@code LongStream} by elements that generated by {@code LongSupplier}.
*
* @param s the {@code LongSupplier} for generated elements
* @return a new infinite sequential {@code LongStream}
* @throws NullPointerException if {@code s} is null
*/
public static LongStream generate(final LongSupplier s) {
N.requireNonNull(s);
return new LongStream(new LongGenerate(s));
}
/**
* Creates a {@code LongStream} by iterative application {@code LongUnaryOperator} function
* to an initial element {@code seed}. Produces {@code LongStream} consisting of
* {@code seed}, {@code f(seed)}, {@code f(f(seed))}, etc.
*
* The first element (position {@code 0}) in the {@code LongStream} 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 LongStream}
* @throws NullPointerException if {@code f} is null
*/
public static LongStream iterate(final long seed, final LongUnaryOperator f) {
N.requireNonNull(f);
return new LongStream(new LongIterate(seed, f));
}
/**
* Creates an {@code LongStream} by iterative application {@code LongUnaryOperator} 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 LongStream iterate(final long seed, final LongPredicate predicate, final LongUnaryOperator op) {
N.requireNonNull(predicate);
return iterate(seed, op).takeWhile(predicate);
}
/**
* Concatenates two streams.
*
* 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 new concatenated stream
* @throws NullPointerException if {@code a} or {@code b} is null
*/
public static LongStream concat(final LongStream a, final LongStream b) {
N.requireNonNull(a);
N.requireNonNull(b);
@SuppressWarnings("resource")
LongStream result = new LongStream(new LongConcat(a.iterator, b.iterator));
return result.onClose(Compose.closeables(a, b));
}
public static LongStream concat(final long[] a, final long[] b) {
return new LongStream(new LongConcat(OfLong.of(a), OfLong.of(b)));
}
private final PrimitiveIterator.OfLong iterator;
private final Params params;
private LongStream(PrimitiveIterator.OfLong iterator) {
this(null, iterator);
}
LongStream(Params params, PrimitiveIterator.OfLong iterator) {
this.params = params;
this.iterator = iterator;
}
/**
* Returns internal {@code LongStream} iterator.
*
* @return internal {@code LongStream} iterator.
*/
public PrimitiveIterator.OfLong iterator() {
return iterator;
}
/**
* Returns a {@code Stream} consisting of the elements of this stream,
* each boxed to an {@code Long}.
*
* This is an lazy intermediate operation.
*
* @return a {@code Stream} consistent of the elements of this stream,
* each boxed to an {@code Long}
*/
public Stream boxed() {
return new Stream<>(params, iterator);
}
/**
* Returns {@code LongStream} with elements that satisfy 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 the predicate used to filter elements
* @return the new stream
*/
public LongStream filter(final LongPredicate predicate) {
return new LongStream(params, new LongFilter(iterator, predicate));
}
/**
* Returns an {@code LongStream} 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 the mapper function used to apply to each element
* @return the new stream
* @see Stream#map(com.landawn.abacus.util.function.Function)
*/
public LongStream map(final LongUnaryOperator mapper) {
return new LongStream(params, new LongMap(iterator, mapper));
}
/**
* 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 LongFunction mapper) {
return new Stream<>(params, new LongMapToObj<>(iterator, mapper));
}
/**
* Returns an {@code IntStream} 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 IntStream}
*/
public IntStream mapToInt(final LongToIntFunction mapper) {
return new IntStream(params, new LongMapToInt(iterator, mapper));
}
/**
* Returns an {@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}
*/
public DoubleStream mapToDouble(final LongToDoubleFunction mapper) {
return new DoubleStream(params, new LongMapToDouble(iterator, 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.
*
*
Example:
*
* mapper: (a) -> [a, a + 5]
* stream: [1, 2, 3, 4]
* result: [1, 6, 2, 7, 3, 8, 4, 9]
*
*
* @param mapper the mapper function used to apply to each element
* @return the new stream
* @see Stream#flatMap(com.landawn.abacus.util.function.Function)
*/
public LongStream flatMap(final LongFunction mapper) {
return new LongStream(params, new LongFlatMap(iterator, mapper));
}
/**
* 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 LongStream distinct() {
return boxed().distinct().mapToLong(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 LongStream sorted() {
return new LongStream(params, new LongSorted(iterator));
}
/**
* Returns a stream consisting of the elements of this stream
* in sorted order 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 LongStream}
*/
public LongStream sorted(Comparator comparator) {
return boxed().sorted(comparator).mapToLong(UNBOX_FUNCTION);
}
/**
* Performs provided action on each element.
*
* This is an intermediate operation.
*
* @param action the action to be performed on each element
* @return the new stream
*/
public LongStream peek(final LongConsumer action) {
return new LongStream(params, new LongPeek(iterator, action));
}
/**
* Returns a {@code LongStream} produced by iterative application of a accumulation function
* to reduction value and next element of the current stream.
* Produces a {@code LongStream} consisting of {@code value1}, {@code acc(value1, value2)},
* {@code acc(acc(value1, value2), value3)}, etc.
*
*
This is an intermediate operation.
*
*
Example:
*
* accumulator: (a, b) -> a + b
* stream: [1, 2, 3, 4, 5]
* result: [1, 3, 6, 10, 15]
*
*
* @param accumulator the accumulation function
* @return the new stream
* @throws NullPointerException if {@code accumulator} is null
* @since 1.1.6
*/
public LongStream scan(final LongBinaryOperator accumulator) {
N.requireNonNull(accumulator);
return new LongStream(params, new LongScan(iterator, accumulator));
}
/**
* Returns a {@code LongStream} produced by iterative application of a accumulation function
* to an initial element {@code identity} and next element of the current stream.
* Produces a {@code LongStream} consisting of {@code identity}, {@code acc(identity, value1)},
* {@code acc(acc(identity, value1), value2)}, etc.
*
* This is an intermediate operation.
*
*
Example:
*
* identity: 0
* accumulator: (a, b) -> a + b
* stream: [1, 2, 3, 4, 5]
* result: [0, 1, 3, 6, 10, 15]
*
*
* @param identity the initial value
* @param accumulator the accumulation function
* @return the new stream
* @throws NullPointerException if {@code accumulator} is null
* @since 1.1.6
*/
public LongStream scan(final long identity, final LongBinaryOperator accumulator) {
N.requireNonNull(accumulator);
return new LongStream(params, new LongScanIdentity(iterator, identity, accumulator));
}
/**
* Takes elements while the predicate returns {@code 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 LongStream}
*/
public LongStream takeWhile(final LongPredicate predicate) {
return new LongStream(params, new LongTakeWhile(iterator, predicate));
}
/**
* Takes elements while the predicate returns {@code false}.
* Once predicate condition is satisfied by an element, the stream
* finishes with this element.
*
* This is an intermediate operation.
*
*
Example:
*
* stopPredicate: (a) -> a > 2
* stream: [1, 2, 3, 4, 1, 2, 3, 4]
* result: [1, 2, 3]
*
*
* @param stopPredicate the predicate used to take elements
* @return the new {@code LongStream}
* @since 1.1.6
*/
public LongStream takeUntil(final LongPredicate stopPredicate) {
return new LongStream(params, new LongTakeUntil(iterator, stopPredicate));
}
/**
* 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 LongStream}
*/
public LongStream dropWhile(final LongPredicate predicate) {
return new LongStream(params, new LongDropWhile(iterator, predicate));
}
/**
* 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 LongStream limit(final long maxSize) {
if (maxSize < 0)
throw new IllegalArgumentException("maxSize cannot be negative");
if (maxSize == 0)
return LongStream.empty();
return new LongStream(params, new LongLimit(iterator, maxSize));
}
/**
* Skips first {@code n} elements and returns {@code LongStream} with remaining elements.
* 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 elements to skip
* @return the new stream
* @throws IllegalArgumentException if {@code n} is negative
*/
public LongStream skip(final long n) {
if (n < 0)
throw new IllegalArgumentException("n cannot be negative");
if (n == 0)
return this;
return new LongStream(params, new LongSkip(iterator, n));
}
/**
* Performs an action for each element of this stream.
*
* This is a terminal operation.
*
* @param action the action to be performed on each element
*/
public void forEach(LongConsumer action) {
while (iterator.hasNext()) {
action.accept(iterator.nextLong());
}
}
/**
* 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 accumulator the accumulation function
* @return the result of the reduction
* @see #sum()
* @see #min()
* @see #max()
*/
public long reduce(long identity, LongBinaryOperator accumulator) {
long result = identity;
while (iterator.hasNext()) {
final long value = iterator.nextLong();
result = accumulator.applyAsLong(result, value);
}
return result;
}
/**
* Performs a reduction on the elements of this stream, using an
* associative accumulation function, and returns an {@code OptionalLong}
* describing the reduced value, if any.
*
* The {@code accumulator} function must be an associative function.
*
*
This is a terminal operation.
*
* @param accumulator the accumulation function
* @return the result of the reduction
* @see #reduce(com.landawn.abacus.util.function.LongBinaryOperator)
*/
public OptionalLong reduce(LongBinaryOperator accumulator) {
boolean foundAny = false;
long result = 0;
while (iterator.hasNext()) {
final long value = iterator.nextLong();
if (!foundAny) {
foundAny = true;
result = value;
} else {
result = accumulator.applyAsLong(result, value);
}
}
return foundAny ? OptionalLong.of(result) : OptionalLong.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 long[] toArray() {
return Operators.toLongArray(iterator);
}
/**
* 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.landawn.abacus.util.function.Supplier, com.landawn.abacus.util.function.BiConsumer)
*/
public R collect(Supplier supplier, ObjLongConsumer accumulator) {
final R result = supplier.get();
while (iterator.hasNext()) {
final long value = iterator.nextLong();
accumulator.accept(result, value);
}
return result;
}
/**
* Returns the sum of elements in this stream.
*
* @return the sum of elements in this stream
*/
public long sum() {
long sum = 0;
while (iterator.hasNext()) {
sum += iterator.nextLong();
}
return sum;
}
/**
* Returns an {@code OptionalLong} describing the minimum element of this
* stream, or an empty optional if this stream is empty.
*
* This is a terminal operation.
*
* @return the minimum element
*/
public OptionalLong min() {
return reduce(new LongBinaryOperator() {
@Override
public long applyAsLong(long left, long right) {
return Math.min(left, right);
}
});
}
/**
* Returns an {@code OptionalLong} describing the maximum element of this
* stream, or an empty optional if this stream is empty.
*
*
This is a terminal operation.
*
* @return the maximum element
*/
public OptionalLong max() {
return reduce(new LongBinaryOperator() {
@Override
public long applyAsLong(long left, long right) {
return Math.max(left, right);
}
});
}
/**
* Returns the count of elements in this stream.
*
*
This is a terminal operation.
*
* @return the count of elements in this stream
*/
public int count() {
int count = 0;
while (iterator.hasNext()) {
iterator.nextLong();
count++;
}
return count;
}
/**
* Returns the average of elements in this stream.
*
*
This is a terminal operation.
*
* @return the average of elements in this stream
*/
public OptionalDouble average() {
long count = 0;
long sum = 0;
while (iterator.hasNext()) {
sum += iterator.nextLong();
count++;
}
if (count == 0)
return OptionalDouble.empty();
return OptionalDouble.of(((double) sum) / count);
}
/**
* Tests whether all elements match the given 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 the predicate used to match elements
* @return {@code true} if any elements of the stream match the provided
* predicate, otherwise {@code false}
*/
public boolean anyMatch(LongPredicate predicate) {
while (iterator.hasNext()) {
if (predicate.test(iterator.nextLong()))
return true;
}
return false;
}
/**
* Tests whether all elements match the given 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 the predicate used to match elements
* @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(LongPredicate predicate) {
while (iterator.hasNext()) {
if (!predicate.test(iterator.nextLong()))
return false;
}
return true;
}
/**
* Tests whether no elements match the given 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 the predicate used to match elements
* @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(LongPredicate predicate) {
while (iterator.hasNext()) {
if (predicate.test(iterator.nextLong()))
return false;
}
return true;
}
/**
* Returns the first element wrapped by {@code OptionalLong} class.
* If stream is empty, returns {@code OptionalLong.empty()}.
*
* This is a short-circuiting terminal operation.
*
* @return an {@code OptionalLong} with first element
* or {@code OptionalLong.empty()} if stream is empty
*/
public OptionalLong findFirst() {
if (iterator.hasNext()) {
return OptionalLong.of(iterator.nextLong());
}
return OptionalLong.empty();
}
/**
* Returns the last element wrapped by {@code OptionalLong} class.
* If stream is empty, returns {@code OptionalLong.empty()}.
*
*
This is a short-circuiting terminal operation.
*
* @return an {@code OptionalLong} with the last element
* or {@code OptionalLong.empty()} if the stream is empty
* @since 1.1.8
*/
public OptionalLong findLast() {
return reduce(new LongBinaryOperator() {
@Override
public long applyAsLong(long left, long right) {
return right;
}
});
}
/**
* Applies custom operator on stream.
*
* Transforming function can return {@code LongStream} for intermediate operations,
* or any value for terminal operation.
*
*
Operator examples:
*
* // Intermediate operator
* public class Zip implements Function<LongStream, LongStream> {
*
* private final LongStream secondStream;
* private final LongBinaryOperator combiner;
*
* public Zip(LongStream secondStream, LongBinaryOperator combiner) {
* this.secondStream = secondStream;
* this.combiner = combiner;
* }
*
* @Override
* public LongStream apply(LongStream firstStream) {
* final PrimitiveIterator.OfLong it1 = firstStream.iterator();
* final PrimitiveIterator.OfLong it2 = secondStream.iterator();
* return LongStream.of(new PrimitiveIterator.OfLong() {
* @Override
* public boolean hasNext() {
* return it1.hasNext() && it2.hasNext();
* }
*
* @Override
* public long nextLong() {
* return combiner.applyAsLong(it1.nextLong(), it2.nextLong());
* }
* });
* }
* }
*
* // Intermediate operator based on existing stream operators
* public class SkipAndLimit implements UnaryOperator<LongStream> {
*
* private final int skip, limit;
*
* public SkipAndLimit(int skip, int limit) {
* this.skip = skip;
* this.limit = limit;
* }
*
* @Override
* public LongStream apply(LongStream stream) {
* return stream.skip(skip).limit(limit);
* }
* }
*
* // Terminal operator
* public class LongSummaryStatistics implements Function<LongStream, long[]> {
* @Override
* public long[] apply(LongStream stream) {
* long count = 0;
* long sum = 0;
* final PrimitiveIterator.OfLong it = stream.iterator();
* while (it.hasNext()) {
* count++;
* sum += it.nextLong();
* }
* return new long[] {count, sum};
* }
* }
*
*
* @param the type of the result
* @param function a transforming function
* @return a result of the transforming function
* @see Stream#chain(com.landawn.abacus.util.function.Function)
* @throws NullPointerException if {@code function} is null
*/
public R __(Function transfer) {
return transfer.apply(this);
}
public void println() {
boxed().println();
}
/**
* Adds close handler to the current stream.
*
* This is an intermediate operation.
*
* @param closeHandler an action to execute when the stream is closed
* @return the new stream with the close handler
* @since 1.1.8
*/
public LongStream onClose(final Runnable closeHandler) {
N.requireNonNull(closeHandler);
final Params newParams;
if (params == null) {
newParams = new Params();
newParams.closeHandler = closeHandler;
} else {
newParams = params;
final Runnable firstHandler = newParams.closeHandler;
newParams.closeHandler = Compose.runnables(firstHandler, closeHandler);
}
return new LongStream(newParams, iterator);
}
/**
* Causes close handler to be invoked if it exists.
* Since most of the stream providers are lists or arrays,
* it is not necessary to close the stream.
*
* @since 1.1.8
*/
@Override
public void close() {
if (params != null && params.closeHandler != null) {
params.closeHandler.run();
params.closeHandler = null;
}
}
private static final ToLongFunction UNBOX_FUNCTION = new ToLongFunction() {
@Override
public long applyAsLong(Long t) {
return t;
}
};
}