Java線程池管理

 

import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPoolManager {

 
 /*
  * 將構造方法訪問修飾符設爲私有，禁止任意實例化。
  */
 private ThreadPoolManager() {}
 
 /*
  *實例化私有的靜態成員變量線程池管理對象
  */
 private static ThreadPoolManager manager = new ThreadPoolManager();
 
  /*
   * 線程池單例創建方法
   */
 public static ThreadPoolManager newInstance() {
   return manager;
 }
 

 // 線程池維護線程的最少數量
 private final static int CORE_POOL_SIZE = 3;

 

 // 線程池維護線程的最大數量
 private final static int MAX_POOL_SIZE = 10;

 

 // 線程池維護線程所允許的空閒時間
 private final static int KEEP_ALIVE_TIME = 0;

 

 // 線程池所使用的緩衝隊列大小
 private final static int WORK_QUEUE_SIZE = 10;

 

 // 任務調度週期
 private final static int TASK_QOS_PERIOD = 10;

 

 // 任務緩衝隊列
 private Queue<Runnable> taskQueue = new LinkedList<Runnable>();

 

  /*
   * 線程池超出界線時將任務加入緩衝隊列
   */
 final RejectedExecutionHandler handler = new RejectedExecutionHandler() {
   public void rejectedExecution(Runnable task, ThreadPoolExecutor executor) {
    taskQueue.offer(task);
   }
 };

 

  /*
   * 將緩衝隊列中的任務重新加載到線程池
   */
 final Runnable accessBufferThread = new Runnable() {
   public void run() {
    if (hasMoreAcquire()) {
     threadPool.execute(taskQueue.poll());
    }
   }
 };

 

  /*
   * 創建一個調度線程池
   */
 final ScheduledExecutorService scheduler = Executors .newScheduledThreadPool(1);

 

  /*
   * 通過調度線程週期性的執行緩衝隊列中任務
   */
 final ScheduledFuture<?> taskHandler = scheduler.scheduleAtFixedRate(
    accessBufferThread, 0, TASK_QOS_PERIOD, TimeUnit.MILLISECONDS);

 

  /*
   * 線程池
   */
 final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(
    CORE_POOL_SIZE, MAX_POOL_SIZE, KEEP_ALIVE_TIME, TimeUnit.SECONDS,
    new ArrayBlockingQueue<Runnable>(WORK_QUEUE_SIZE), this.handler);

 

  /*
   * 消息隊列檢查方法
   */
 private boolean hasMoreAcquire() {
   return !taskQueue.isEmpty();
 }

 

  /*
   * 向線程池中添加任務方法
   */
 public void addExecuteTask(Runnable task) {
   if (task != null) {
    threadPool.execute(task);
   }
 }

 
 
}