ExecutorService service = new ThreadPoolExecutor(10, 10, 1000L,
TimeUnit.MILLISECONDS, new ArrayBlockingQueue<Runnable>(10, true), new
ThreadPoolExecutor.CallerRunsPolicy());
问题陈述是：-
每个线程都使用unique IDbetween 1 and 1000and 程序必须运行 for 60 minutes or more，在我检查时我run method得到了id as zero几次(if(id==0))，我把断点放在那个循环下，我不知道为什么？由于 availableExistingIds 的值在 1 到 1000 之间，所以我不知道这是从哪里来的zero is coming in my id？
class IdPool {
private final LinkedList<Integer> availableExistingIds = new LinkedList<Integer>();
public IdPool() {
for (int i = 1; i <= 1000; i++) {
availableExistingIds.add(i);
}
}
public synchronized Integer getExistingId() {
return availableExistingIds.removeFirst();
}
public synchronized void releaseExistingId(Integer id) {
availableExistingIds.add(id);
}
}
class ThreadNewTask implements Runnable {
private IdPool idPool;
private int id;
public ThreadNewTask(IdPool idPool) {
this.idPool = idPool;
}
public void run() {
try {
id = idPool.getExistingId();
//Anything wrong here?
if(id==0) {
System.out.println("Found Zero");
}
someMethod(id);
} catch (Exception e) {
System.out.println(e);
} finally {
idPool.releaseExistingId(id);
}
}
// This method needs to be synchronized or not?
private synchronized void someMethod(Integer id) {
System.out.println("Task: " +id);
// and do other calcuations whatever you need to do in your program
}
}
以下是程序开始的主要课程 -
public class TestingPool {
public static void main(String[] args) throws InterruptedException {
int size = 10;
int durationOfRun = 60;
IdPool idPool = new IdPool();
// create thread pool with given size
ExecutorService service = new ThreadPoolExecutor(size, size, 500L, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<Runnable>(size), new ThreadPoolExecutor.CallerRunsPolicy());
// queue some tasks
long startTime = System.currentTimeMillis();
long endTime = startTime + (durationOfRun * 60 * 1000L);
// Running it for 60 minutes
while(System.currentTimeMillis() <= endTime) {
service.submit(new ThreadNewTask(idPool));
}
// wait for termination
service.shutdown();
service.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
}
}
更新：-
我想在这里使用 ArrayBlockingQueue ，这样当没有可用的 id 时它不会崩溃，而是等待一个可用。谁能建议我如何在这里使用它？
实施 BlockingQueue 后的代码更改。
public void run() {
System.err.println(command.getDataCriteria());
if(command.getDataCriteria().equals(PDSLnPConstants.DATA_CRITERIA_PREVIOUS)) {
try {
System.out.println(command.getDataCriteria());
// Getting existing id from the pool
existId = existPool.take();
attributeGetSetMethod(existId);
} catch (Exception e) {
getLogger().log(LogLevel.ERROR, e.getLocalizedMessage());
} finally {
// And releasing that existing ID for re-use
existPool.offer(existId);
}
}
else if(command.getDataCriteria().equals(PDSLnPConstants.DATA_CRITERIA_NEW)) {
try {
System.out.println(command.getDataCriteria());
// Getting new id from the pool
newId = newPool.take();
attributeGetSetMethod(newId);
} catch (Exception e) {
getLogger().log(LogLevel.ERROR, e.getLocalizedMessage());
} finally {
// And releasing that new ID for re-use
newPool.offer(newId);
}
}
}
我刚刚注意到的一件奇怪的事情是-在下面else if loop，如果您在下面看到我的上面的代码，run method那么command.getDataCriteria() is Previous它也被输入到else if block(which is for New)其中不应该发生在我正在做的事情.equals check？为什么会这样？
else if(command.getDataCriteria().equals(PDSLnPConstants.DATA_CRITERIA_NEW)) {