Java实现FIFO任务调度队列策略

Z时代
2024-01-10
分类：IT

前言

在工作中，很多高并发的场景中，我们会用到队列来实现大量的任务请求。当任务需要某些特殊资源的时候，我们还需要合理的分配资源，让队列中的任务高效且有序完成任务。熟悉分布式的话，应该了解yarn的任务调度算法。本文主要用java实现一个FIFO（先进先出调度器），这也是常见的一种调度方式。

FIFO任务调度器架构

主要实现的逻辑可以归纳为：

1、任务队列主要是单队列，所有任务按照顺序进入队列后，也会按照顺序执行。

2、如果任务无法获得资源，则将任务塞回队列原位置。

示例代码

Maven依赖如下：


      	<dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
                <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.5.2</version>
        </dependency>

具体的原理就不细说了，通过代码我们看看FIFO任务调度策略是什么玩的吧。下面的代码也可以作为参考。我们会使用到一个双向阻塞队列LinkedBlockingDeque。后面的代码说明会提到。


package ai.guiji.csdn.dispatch;
import cn.hutool.core.thread.ThreadUtil;
import lombok.Builder;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.concurrent.CustomizableThreadFactory;
import java.util.Random;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.IntStream;
/**
 * @Program: csdn @ClassName: FIFODemo @Author: 剑客阿良_ALiang @Date: 2021-12-24 21:21 @Description:
 * fifo队列 @Version: V1.0
 */
@Slf4j
public class FIFODemo {
  private static final LinkedBlockingDeque<Task> TASK_QUEUE = new LinkedBlockingDeque<>();
  private static final ConcurrentHashMap<Integer, LinkedBlockingQueue<Resource>> RESOURCE_MAP =
      new ConcurrentHashMap<>();
  private static final ExecutorService TASK_POOL =
      new ThreadPoolExecutor(
          8,
          16,
          0L,
          TimeUnit.MILLISECONDS,
          new LinkedBlockingQueue<>(),
          new CustomizableThreadFactory("TASK-THREAD-"),
          new ThreadPoolExecutor.AbortPolicy());
  private static final ScheduledExecutorService ENGINE_POOL =
      Executors.newSingleThreadScheduledExecutor(new CustomizableThreadFactory("ENGINE-"));
  private static final AtomicInteger CODE_BUILDER = new AtomicInteger(0);
  @Data
  @Builder
  private static class Resource {
    private Integer rId;
    private Type type;
  }
  @Data
  @Builder
  private static class Task implements Runnable {
    private Integer tId;
    private Runnable work;
    private Type type;
    private Resource resource;
    @Override
    public void run() {
      log.info("[{}]任务，使用资源编号:[{}]", tId, resource.getRId());
      try {
        work.run();
      } catch (Exception exception) {
        exception.printStackTrace();
      } finally {
        log.info("[{}]任务结束，回归资源", tId);
        returnResource(resource);
      }
    }
  }
  private enum Type {
    /** 资源类型 */
    A("A资源", 1),
    B("B资源", 2),
    C("C资源", 3);
    private final String desc;
    private final Integer code;
    Type(String desc, Integer code) {
      this.desc = desc;
      this.code = code;
    }
    public String getDesc() {
      return desc;
    }
    public Integer getCode() {
      return code;
    }
  }
  public static void initResource() {
    Random random = new Random();
    int aCount = random.nextInt(10) + 1;
    int bCount = random.nextInt(10) + 1;
    int cCount = random.nextInt(10) + 1;
    RESOURCE_MAP.put(Type.A.getCode(), new LinkedBlockingQueue<>());
    RESOURCE_MAP.put(Type.B.getCode(), new LinkedBlockingQueue<>());
    RESOURCE_MAP.put(Type.C.getCode(), new LinkedBlockingQueue<>());
    IntStream.rangeClosed(1, aCount)
        .forEach(
            a ->
                RESOURCE_MAP
                    .get(Type.A.getCode())
                    .add(Resource.builder().rId(a).type(Type.A).build()));
    IntStream.rangeClosed(1, bCount)
        .forEach(
            a ->
                RESOURCE_MAP
                    .get(Type.B.getCode())
                    .add(Resource.builder().rId(a).type(Type.B).build()));
    IntStream.rangeClosed(1, cCount)
        .forEach(
            a ->
                RESOURCE_MAP
                    .get(Type.C.getCode())
                    .add(Resource.builder().rId(a).type(Type.C).build()));
    log.info("初始化资源A数量:{},资源B数量:{},资源C数量:{}", aCount, bCount, cCount);
  }
  public static Resource extractResource(Type type) {
    return RESOURCE_MAP.get(type.getCode()).poll();
  }
  public static void returnResource(Resource resource) {
    log.info("开始归还资源，rId:{},资源类型:{}", resource.getRId(), resource.getType().getDesc());
    RESOURCE_MAP.get(resource.getType().code).add(resource);
    log.info("归还资源完成，rId:{},资源类型:{}", resource.getRId(), resource.getType().getDesc());
  }
  public static void enginDo() {
    ENGINE_POOL.scheduleAtFixedRate(
        () -> {
          Task task = TASK_QUEUE.poll();
          if (task == null) {
            log.info("任务队列为空，无需要执行的任务");
          } else {
            Resource resource = extractResource(task.getType());
            if (resource == null) {
              log.info("[{}]任务无法获取[{}]，返回队列", task.getTId(), task.getType().getDesc());
              TASK_QUEUE.addFirst(task);
            } else {
              task.setResource(resource);
              TASK_POOL.submit(task);
            }
          }
        },
        0,
        1,
        TimeUnit.SECONDS);
  }
  public static void addTask(Runnable runnable, Type type) {
    Integer tId = CODE_BUILDER.incrementAndGet();
    Task task = Task.builder().tId(tId).type(type).work(runnable).build();
    log.info("提交任务[{}]到任务队列", tId);
    TASK_QUEUE.add(task);
  }
  public static void main(String[] args) {
    initResource();
    enginDo();
    Random random = new Random();
    ThreadUtil.sleep(5000);
    IntStream.range(0, 10)
        .forEach(
            a -> addTask(() -> ThreadUtil.sleep(random.nextInt(10) + 1, TimeUnit.SECONDS), Type.A));
    IntStream.range(0, 10)
        .forEach(
            a -> addTask(() -> ThreadUtil.sleep(random.nextInt(10) + 1, TimeUnit.SECONDS), Type.B));
    IntStream.range(0, 10)
        .forEach(
            a -> addTask(() -> ThreadUtil.sleep(random.nextInt(10) + 1, TimeUnit.SECONDS), Type.C));
  }
}