Package: StreamUtils$1

StreamUtils$1

name	instruction	branch	complexity	line	method
tryAdvance(Consumer)	M: 0 C: 23 100%	M: 0 C: 4 100%	M: 0 C: 3 100%	M: 0 C: 4 100%	M: 0 C: 1 100%
{...}	M: 0 C: 14 100%	M: 0 C: 0 100%	M: 0 C: 1 100%	M: 0 C: 1 100%	M: 0 C: 1 100%

Coverage

1: /*
2: * *************************************************************************************************************************************************************
3: *
4: * TheseFoolishThings: Miscellaneous utilities
5: * http://tidalwave.it/projects/thesefoolishthings
6: *
7: * Copyright (C) 2009 - 2024 by Tidalwave s.a.s. (http://tidalwave.it)
8: *
9: * *************************************************************************************************************************************************************
10: *
11: * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
12: * You may obtain a copy of the License at
13: *
14: * http://www.apache.org/licenses/LICENSE-2.0
15: *
16: * 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
17: * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
18: *
19: * *************************************************************************************************************************************************************
20: *
21: * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
22: * git clone https://github.com/tidalwave-it/thesefoolishthings-src
23: *
24: * *************************************************************************************************************************************************************
25: */
26: package it.tidalwave.util;
27:
28: import javax.annotation.Nonnull;
29: import java.time.Instant;
30: import java.time.LocalDateTime;
31: import java.time.ZoneId;
32: import java.time.ZoneOffset;
33: import java.util.Random;
34: import java.util.Spliterator;
35: import java.util.Spliterators;
36: import java.util.function.BiFunction;
37: import java.util.function.Consumer;
38: import java.util.stream.Stream;
39: import java.util.stream.StreamSupport;
40: import lombok.AccessLevel;
41: import lombok.NoArgsConstructor;
42:
43: /***************************************************************************************************************************************************************
44: *
45: * A collection of operations on {@link Stream}s.
46: *
47: * @author Fabrizio Giudici
48: * @since 3.2-ALPHA-12
49: * @it.tidalwave.javadoc.draft
50: *
51: **************************************************************************************************************************************************************/
52: @NoArgsConstructor(access = AccessLevel.PRIVATE)
53: public final class StreamUtils
54: {
55: /***********************************************************************************************************************************************************
56: * Zips two streams.
57: *
58: * @param streamA the first {@link Stream}
59: * @param streamB the second {@link Stream}
60: * @param <A> the type of elements of the first {@link Stream}
61: * @param <B> the type of elements of the second {@link Stream}
62: * @return the zipped {@link Stream} of {@link Pair}s
63: * @see #zip(Stream, Stream, BiFunction)
64: * @since 3.2-ALPHA-20
65: **********************************************************************************************************************************************************/
66: @Nonnull
67: public static <A, B> Stream<Pair<A, B>> zip (@Nonnull final Stream<? extends A> streamA,
68: @Nonnull final Stream<? extends B> streamB)
69: {
70: return zip(streamA, streamB, Pair::of);
71: }
72:
73: /***********************************************************************************************************************************************************
74: * Zips two streams.
75: *
76: * @param streamA the first {@link Stream}
77: * @param streamB the second {@link Stream}
78: * @param zipper the zipping function
79: * @param <A> the type of elements of the first {@link Stream}
80: * @param <B> the type of elements of the second {@link Stream}
81: * @param <R> the type of elements of the zipped {@link Stream}
82: * @return the zipped {@link Stream}
83: * @see #zip(Stream, Stream)
84: * @since 3.2-ALPHA-12
85: **********************************************************************************************************************************************************/
86: @Nonnull
87: public static <A, B, R> Stream<R> zip (@Nonnull final Stream<? extends A> streamA,
88: @Nonnull final Stream<? extends B> streamB,
89: @Nonnull final BiFunction<? super A, ? super B, ? extends R> zipper)
90: {
91: final var parallel = streamA.isParallel() || streamB.isParallel();
92: final var sa = streamA.spliterator();
93: final var sb = streamB.spliterator();
94: final var characteristics =
95: sa.characteristics() & sb.characteristics() & (Spliterator.SIZED | Spliterator.ORDERED);
96: final var a = Spliterators.iterator(sa);
97: final var b = Spliterators.iterator(sb);
98: final var estSize = Math.min(sa.estimateSize(), sb.estimateSize());
99: return StreamSupport.stream(new Spliterators.AbstractSpliterator<R>(estSize, characteristics)
100: {
101: @Override
102: public boolean tryAdvance (@Nonnull final Consumer<? super R> action)
103: {
104:• if (a.hasNext() && b.hasNext())
105: {
106: action.accept(zipper.apply(a.next(), b.next()));
107: return true;
108: }
109:
110: return false;
111: }
112: },
113: parallel)
114: .onClose(streamA::close)
115: .onClose(streamB::close);
116: }
117:
118: /***********************************************************************************************************************************************************
119: * Returns a {@code Stream} of random {@link LocalDateTime}s, in the given range.
120: *
121: * @param seed the random seed
122: * @param from the lower bound of the range (included)
123: * @param to the upper bound of the range (excluded)
124: * @return the stream
125: * @since 3.2-ALPHA-19
126: **********************************************************************************************************************************************************/
127: @Nonnull
128: public static Stream<LocalDateTime> randomLocalDateTimeStream (final long seed,
129: @Nonnull final LocalDateTime from,
130: @Nonnull final LocalDateTime to)
131: {
132: final var zo = ZoneOffset.UTC;
133: return new Random(seed)
134: .longs(from.toEpochSecond(zo), to.toEpochSecond(zo))
135: .mapToObj(l -> LocalDateTime.ofInstant(Instant.ofEpochSecond(l), ZoneId.of(zo.getId())));
136: }
137: }