Java 自定义多线程:限制要并行执行的某些类型的任务数量,而不限制其他类型的任务
我有三种类型的任务:Java 自定义多线程:限制要并行执行的某些类型的任务数量,而不限制其他类型的任务,java,multithreading,concurrency,threadpool,Java,Multithreading,Concurrency,Threadpool,我有三种类型的任务:A、B、C 我想在N个线程中并行运行这些任务。假设任务列表如下所示: A, B, C, B, C, A, B, C 当然,我可以使用ExecutorService实现多线程执行,但问题是我一次最多需要执行一个C类型的任务。其他C类型的任务必须顺序执行,但与a和/或B任务并行执行 例如,3线程执行器可能处于以下任何状态: A B C A A A A C B B B C B B B B C A C A B C ... (允许一次执行多个A或B类任务,但一次最多只能执
A、B、C
我想在N个线程中并行运行这些任务。假设任务列表如下所示:
A, B, C, B, C, A, B, C
当然,我可以使用ExecutorService
实现多线程执行,但问题是我一次最多需要执行一个C
类型的任务。其他C
类型的任务必须顺序执行,但与a
和/或B
任务并行执行
例如,3线程执行器可能处于以下任何状态:
A B C
A A A
A C B
B B C
B B B
B C
A C
A B
C
...
(允许一次执行多个A或B类任务,但一次最多只能执行一个C类任务)
有什么方法可以在Java中实现这一点吗
更新
这就是我想到的方法这是正确的吗
在这里,我通过ExecutorService
执行所有任务,在执行过程中,我将检查是否有任何其他C任务正在运行。如果没有,我将执行其他任务,我将把它添加到一个队列中,该队列将在成功完成任何其他任务时退出队列,并且我将检查任何C任务是否正在运行
public class Test {
public void startExecution() {
Queue<String> runQ = new LinkedList<>();
ThreadPool exec = (ThreadPool) Executors.newFixedThreadPool(RunSettings.getRunSettings().getThreadCount());
while (!runQ.isEmpty() && !SystemDefaults.stopExecution.get()) {
String TaskName = runQ.remove();
Task t = new Task(TaskName);
exec.execute(t, TaskName);
}
exec.shutdown();
if (exec.awaitTermination(RunSettings.getRunSettings().getExecutionTimeOut(), TimeUnit.MINUTES)) {
System.out.println("[CONTROL: ALL TEST TASKS COMPLETED SUCCESSFULLY.]");
} else {
System.out.println("[CONTROL: ALL THE TEST TASKS DID NOT COMPLETE SUCCESSFULLY IN STIPULATED TIME. FORCEFULLY FINALIZING.]");
exec.shutdownNow();
}
}
}
公共类测试{
公共无效开始执行(){
队列runQ=newlinkedlist();
ThreadPool exec=(ThreadPool)Executors.newFixedThreadPool(RunSettings.getRunSettings().getThreadCount());
而(!runQ.isEmpty()&&!SystemDefaults.stopExecution.get()){
字符串TaskName=runQ.remove();
任务t=新任务(任务名称);
exec.execute(t,任务名);
}
exec.shutdown();
if(exec.waittermination(RunSettings.getRunSettings().getExecutionTimeOut(),TimeUnit.MINUTES)){
System.out.println(“[控制:所有测试任务成功完成]”;
}否则{
System.out.println(“[控制:所有测试任务未在规定时间内成功完成。强制完成]”;
exec.shutdownNow();
}
}
}
我创建的线程池
public class ThreadPool extends ThreadPoolExecutor {
public ThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
}
final String CTask = "TaskC";
Map<Runnable, String> TaskPool = new HashMap<>();
Queue<Runnable> TaskCList = new LinkedList<>();
@Override
protected void afterExecute(Runnable r, Throwable t) {
super.afterExecute(r, t);
if (TaskPool.containsKey(r)) {
TaskPool.remove(r);
}
if (!TaskPool.containsValue(CTask) && !TaskCList.isEmpty()) {
Runnable ieRun = TaskCList.remove();
super.execute(ieRun);
TaskPool.put(ieRun, CTask);
}
}
public void execute(Runnable command, String TaskType) {
if (TaskPool.containsValue(TaskType)
&& TaskType.equalsIgnoreCase(CTask)) {
System.out.println("Another Instance of " + CTask + " Running");
TaskCList.add(command);
} else {
super.execute(command);
TaskPool.put(command, TaskType);
}
}
}
公共类ThreadPool扩展ThreadPoolExecutor{
公共线程池(int corePoolSize、int maximumPoolSize、long keepAliveTime、TimeUnit、BlockingQueue workQueue){
super(corePoolSize、maximumPoolSize、keepAliveTime、unit、workQueue);
}
最终字符串CTask=“TaskC”;
Map TaskPool=new HashMap();
Queue TaskCList=new LinkedList();
@凌驾
执行后受保护的无效(可运行的r、可丢弃的t){
super.afterExecute(r,t);
if(任务池容器(r)){
任务池。删除(r);
}
如果(!TaskPool.containsValue(CTask)&&&!TaskCList.isEmpty()){
Runnable ieRun=TaskCList.remove();
超级执行(ieRun);
TaskPool.put(ieRun,CTask);
}
}
public void execute(可运行命令,字符串TaskType){
if(TaskPool.containsValue(TaskType)
&&TaskType.equalsIgnoreCase(CTask)){
System.out.println(“另一个“+CTask+”正在运行的实例”);
TaskCList.add(命令);
}否则{
super.execute(命令);
TaskPool.put(命令,任务类型);
}
}
}
最简单的方法是创建两个执行器:一个单线程执行器用于C类型的任务,另一个多线程执行器用于其他类型的任务:
class ExecutorWrapper {
private ExecutorService forC = Executors.newSingleThreadExecutor();
private ExecutorService forAnother = Executors.newFixedThreadPool(THREAD_NUMBER);
public void acceptTask(Runnable r) {
if (r instanceof TaskC) {
forC.execute(r);
} else {
forAnother.execute(r);
}
}
}
现在,任何C类型的任务都将在执行器内部队列中等待,直到另一个此类任务完成
如果不希望创建另一个执行器,则需要实现某种并发控制,因为可能会发生争用情况,这种并发控制要复杂得多,而且很难调试。我可以提出解决方案草案,但没有代码:
Callable
包装任务C,并调用Future#get
方法来实现,该方法将一直阻止任务完成看起来您所需要做的就是使任务C
同步。下面的一些测试代码似乎证明了这一点——尽管没有失败并不总是意味着成功
结果清楚地表明A和B是并行运行的,但从来没有C
static enum Task implements Callable<Void> {
A,
B,
C {
@Override
public synchronized Void call() throws Exception {
if (running.get(this).get() != 0) {
System.out.println("FAIL!");
}
return super.call();
}
};
// How many of each are running.
static Map<Task, AtomicInteger> running = Stream.of(Task.values())
.collect(
Collectors.toMap(
(t) -> t,
(t) -> new AtomicInteger(0),
(x, y) -> x,
() -> new EnumMap<Task, AtomicInteger>(Task.class)));
// List all running tasks.
private String runningList() {
StringBuilder s = new StringBuilder();
running.entrySet().stream().forEach((r) -> {
if (r.getValue().get() != 0) {
s.append(r.getKey()).append("=").append(r.getValue()).append(",");
}
});
return s.toString();
}
static final Random random = new Random();
@Override
public Void call() throws Exception {
System.out.println("Running " + name() + " with " + runningList());
// Mark me running.
running.get(this).getAndIncrement();
// Hang around for a bit.
Thread.sleep(random.nextInt(1000));
// Mark me not running.
running.get(this).getAndDecrement();
return null;
}
}
// The pool.
static ExecutorService pool = Executors.newFixedThreadPool(5);
// The tasks.
static Task[] tasks = new Task[]{Task.A, Task.B, Task.C, Task.B, Task.C, Task.A, Task.B, Task.C,};
public void test() throws InterruptedException {
// Run 10 times.
for (int i = 0; i < 10; i++) {
pool.invokeAll(Arrays.asList(tasks));
}
pool.shutdown();
pool.awaitTermination(10, TimeUnit.SECONDS);
}
静态枚举任务实现可调用{
A.
B
C{
@凌驾
public synchronized Void call()引发异常{
if(running.get(this.get()!=0){
System.out.println(“失败!”);
}
返回super.call();
}
};
//每个都有多少人在跑步。
静态映射运行=Stream.of(Task.values())
.收集(
汤姆(
(t) ->t,
(t) ->新的原子整数(0),
(x,y)->x,
()->新的枚举映射(Task.class));
//列出所有正在运行的任务。
私有字符串runningList(){
StringBuilder s=新的StringBuilder();
正在运行.entrySet().stream().forEach((r)->{
如果(r.getValue().get()!=0){
s、 append(r.getKey()).append(“=”).append(r.getValue()).append(“,”);
}
});
返回s.toString();
}
静态最终随机=新随机();
@凌驾
public Void call()引发异常{
System.out.println(“正在运行“+name()+”和“+runningList()”);
//让我跑吧。
正在运行.get(this.getAndIncrement();
//亨格尔
public class Test {
public void startExecution() {
Queue<String> runQ = new LinkedList<>();
ThreadPool threadPool = new ThreadPool(threadCount,timeOut);
while (!runQ.isEmpty()) {
String TaskName = runQ.remove();
Task t = new Task(TaskName);
threadPool.execute(t, TaskName);
}
if (threadPool.awaitTermination(timeOut, TimeUnit.MINUTES)) {
System.out.println("[CONTROL: ALL TEST TASKS COMPLETED SUCCESSFULLY.]");
} else {
System.out.println("[CONTROL: ALL THE TEST TASKS DID NOT COMPLETE SUCCESSFULLY IN STIPULATED TIME. FORCEFULLY FINALIZING.]");
threadPool.shutdownNow();
}
}
}
public class ThreadPool extends ThreadPoolExecutor {
public ThreadPool(int threadCount, long keepAliveTime) {
super(threadCount, threadCount, keepAliveTime, TimeUnit.MINUTES, new LinkedBlockingQueue<Runnable>());
}
final String CTask = "TaskC";
Map<Runnable, String> TaskPool = new HashMap<>();
Queue<Runnable> TaskCList = new LinkedList<>();
@Override
protected synchronized void afterExecute(Runnable r, Throwable t) {
super.afterExecute(r, t);
System.out.println(TaskPool.get(r) + "Finished");
if (TaskPool.containsKey(r)) {
TaskPool.remove(r);
}
if (TaskCList.isEmpty()) {
super.shutdown();
}
if (!TaskPool.containsValue(CTask) && !TaskCList.isEmpty()) {
if (super.getActiveCount() < super.getCorePoolSize()) {
System.out.println("Trying to execute Other C Tasks");
Runnable ieRun = TaskCList.remove();
super.execute(ieRun);
TaskPool.put(ieRun, CTask);
}
}
}
public synchronized void execute(Runnable command, String TaskType) {
if (TaskPool.containsValue(TaskType)
&& TaskType.equalsIgnoreCase(CTask)) {
System.out.println("Another Instance of TaskC Running");
System.out.println("Added for future Execution");
TaskCList.add(command);
} else {
System.out.println("Adding " + TaskType + " to execution");
TaskPool.put(command, TaskType);
super.execute(command);
}
}