Class ParallelStreamUtil

java.lang.Object
cloud.opencode.base.core.stream.ParallelStreamUtil
public final class ParallelStreamUtil extends Object
Parallel Stream Utility - Smart parallel/sequential stream selection 并行流工具类 - 智能选择并行/顺序流

Provides utilities for intelligent parallel stream usage based on collection size.

提供基于集合大小智能选择并行流使用的工具。

Features | 主要功能:

  • Smart parallel/sequential selection by threshold - 按阈值智能选择并行/顺序流
  • CPU-aware threshold calculation - CPU 感知的阈值计算
  • Force parallel/sequential methods - 强制并行/顺序流方法
  • Parallelism recommendations - 并行推荐

Usage Examples | 使用示例:

// Smart stream selection - 智能流选择
Stream<String> stream = ParallelStreamUtil.stream(list);

// Check if parallel recommended - 检查是否推荐并行
boolean parallel = ParallelStreamUtil.isParallelRecommended(list.size());

// Force parallel - 强制并行
Stream<String> parallel = ParallelStreamUtil.parallelStream(list);

Security | 安全性:

  • Thread-safe: Yes (stateless) - 线程安全: 是 (无状态)
  • Null-safe: Yes (returns empty stream on null) - 空值安全: 是

Performance | 性能特性:

  • Time complexity: O(n/p) where n = elements, p = parallelism - O(n/p), n为元素数, p为并行度
  • Space complexity: O(n) for stream pipeline - 流管道 O(n)
Since:
JDK 25, opencode-base-core V1.0.0
Author:
Leon Soo www.LeonSoo.com
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    static int
    getAvailableProcessors()
    Gets the available processor count 获取可用处理器数量
    static int
    getParallelism()
    Gets the ForkJoinPool parallelism 获取 ForkJoinPool 并行度
    static int
    getRecommendedThreshold()
    Gets the recommended parallel threshold 获取推荐的并行阈值
    static boolean
    isParallelRecommended(int size)
    Checks if parallel stream is recommended 检查是否推荐使用并行流
    static boolean
    isParallelRecommended(int size, int threshold)
    Checks if parallel stream is recommended (custom threshold) 检查是否推荐使用并行流（自定义阈值）
    static <T> Stream<T>
    parallelStream(Collection<T> collection)
    Forces a parallel stream 强制使用并行流
    static <T> Stream<T>
    sequentialStream(Collection<T> collection)
    Forces a sequential stream 强制使用顺序流
    static <T> Stream<T>
    stream(Collection<T> collection)
    Selects sequential or parallel stream based on collection size 根据集合大小智能选择顺序/并行流
    static <T> Stream<T>
    stream(Collection<T> collection, int threshold)
    Selects sequential or parallel stream based on collection size (custom threshold) 根据集合大小智能选择顺序/并行流（自定义阈值）
    static <T> Stream<T>
    toParallelIf(Stream<T> stream, boolean condition)
    Converts the stream to parallel if the condition is met 将流转为并行流（如果条件满足）
    static <T> Stream<T>
    toSequential(Stream<T> stream)
    Converts the stream to sequential 将流转为顺序流

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • getRecommendedThreshold

      public static int getRecommendedThreshold()
      Gets the recommended parallel threshold 获取推荐的并行阈值

      基于 CPU 核心数计算，通常为每核心 1000 个元素

    • stream

      public static <T> Stream<T> stream(Collection<T> collection)
      Selects sequential or parallel stream based on collection size 根据集合大小智能选择顺序/并行流

    • stream

      public static <T> Stream<T> stream(Collection<T> collection, int threshold)
      Selects sequential or parallel stream based on collection size (custom threshold) 根据集合大小智能选择顺序/并行流（自定义阈值）

    • isParallelRecommended

      public static boolean isParallelRecommended(int size)
      Checks if parallel stream is recommended 检查是否推荐使用并行流

    • isParallelRecommended

      public static boolean isParallelRecommended(int size, int threshold)
      Checks if parallel stream is recommended (custom threshold) 检查是否推荐使用并行流（自定义阈值）

    • getAvailableProcessors

      public static int getAvailableProcessors()
      Gets the available processor count 获取可用处理器数量

    • getParallelism

      public static int getParallelism()
      Gets the ForkJoinPool parallelism 获取 ForkJoinPool 并行度

    • sequentialStream

      public static <T> Stream<T> sequentialStream(Collection<T> collection)
      Forces a sequential stream 强制使用顺序流

    • parallelStream

      public static <T> Stream<T> parallelStream(Collection<T> collection)
      Forces a parallel stream 强制使用并行流

    • toParallelIf

      public static <T> Stream<T> toParallelIf(Stream<T> stream, boolean condition)
      Converts the stream to parallel if the condition is met 将流转为并行流（如果条件满足）

    • toSequential

      public static <T> Stream<T> toSequential(Stream<T> stream)
      Converts the stream to sequential 将流转为顺序流