Java并发编程学习17-线程池的使用（配置和扩展ThreadPoolExecutor）

    public ThreadPoolExecutor(int corePoolSize,
                              int maximumPoolSize,
                              long keepAliveTime,
                              TimeUnit unit,
                              BlockingQueue<Runnable> workQueue,
                              ThreadFactory threadFactory,
                              RejectedExecutionHandler handler) {
        if (corePoolSize < 0 ||
            maximumPoolSize <= 0 ||
            maximumPoolSize < corePoolSize ||
            keepAliveTime < 0)
            throw new IllegalArgumentException();
        if (workQueue == null || threadFactory == null || handler == null)
            throw new NullPointerException();
        this.corePoolSize = corePoolSize;
        this.maximumPoolSize = maximumPoolSize;
        this.workQueue = workQueue;
        this.keepAliveTime = unit.toNanos(keepAliveTime);
        this.threadFactory = threadFactory;
        this.handler = handler;
    }

public class MyRejectedExecutionHandler implements RejectedExecutionHandler {
    @Override
    public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
        // 自定义饱和策略的处理逻辑
    }
}

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 4, 60, TimeUnit.SECONDS,
        new ArrayBlockingQueue<>(10), new MyThreadFactory(), new MyRejectedExecutionHandler());

ThreadPoolExecutor executor = new ThreadPoolExecutor(N_THREADS, N_THREADS, 0L, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(CAPACITY));

executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());

@ThreadSafe
public class BoundedExecutor {
    private final Executor exec;
    
    private final Semaphore semaphore;

    public BoundedExecutor(Executor exec, int bound) {
        this.exec = exec;
        this.semaphore = new Semaphore(bound);
    }
    
    public void submitTask(final Runnable command) throws InterruptedException {
        semaphore.acquire();
        try {
            exec.execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        command.run();
                    } finally {
                        semaphore.release();
                    }
                }
            });
        } catch (RejectedExecutionException e) {
            semaphore.release();
        }
    }
}

public interface ThreadFactory {
    Thread newThread(Runnable r);
}

public class MyThreadFactory implements ThreadFactory {
    private final String poolName;

    public MyThreadFactory(String poolName) {
        this.poolName = poolName;
    }

    @Override
    public Thread newThread(Runnable runnable) {
        return new MyAppThread(runnable, poolName);
    }
}

public class MyAppThread extends Thread {

    public static final String DEFAULT_NAME = "MyAppThread";

    private static volatile boolean debugLifecycle = false;

    private static final AtomicInteger created = new AtomicInteger();

    private static final AtomicInteger alive = new AtomicInteger();

    private static final Logger LOGGER = Logger.getAnonymousLogger();

    public MyAppThread(Runnable runnable) {
        this(runnable, DEFAULT_NAME);
    }

    public MyAppThread(Runnable runnable, String poolName) {
        super(runnable, poolName + "-" + created.incrementAndGet());
        setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Thread t, Throwable e) {
                LOGGER.log(Level.SEVERE, "UNCAUGHT in thread " + t.getName(), e);
            }
        });
    }

    @Override
    public void run() {
        // 复制 debug 标志以确保一致的值
        boolean debug = debugLifecycle;
        if (debug)
            LOGGER.log(Level.FINE, "Created " + getName());
        try {
            alive.incrementAndGet();
            super.run();
        } finally {
            alive.decrementAndGet();
            if (debug)
                LOGGER.log(Level.FINE, "Exiting " + getName());
        }
    }

    public static int getThreadsCreated() {
        return created.get();
    }

    public static int getThreadsAlive() {
        return alive.get();
    }

    public static boolean getDebug() {
        return debugLifecycle;
    }

    public static void setDebug(boolean b) {
        debugLifecycle = b;
    }
}

    ExecutorService exec = Executors.newCachedThreadPool();
    if (exec instanceof ThreadPoolExecutor)
        ((ThreadPoolExecutor) exec).setCorePoolSize(10);
    else
        throw new AssertionError("Oops, bad assumption");

public class TimingThreadPool extends ThreadPoolExecutor {
    private final ThreadLocal<Long> startTime = new ThreadLocal<>();

    private final Logger LOGGER = Logger.getLogger("TimingThreadPool");

    private final AtomicLong numTasks = new AtomicLong();

    private final AtomicLong totalTime = new AtomicLong();

    public TimingThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
    }

    public TimingThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory) {
        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory);
    }

    public TimingThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler) {
        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, handler);
    }

    public TimingThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) {
        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler);
    }

    @Override
    protected void beforeExecute(Thread t, Runnable r) {
        super.beforeExecute(t, r);
        LOGGER.fine(String.format("Thread %s: start %s", t, r));
        startTime.set(System.nanoTime());
    }

    @Override
    protected void afterExecute(Runnable r, Throwable t) {
        try {
            long endTime = System.nanoTime();
            long taskTime = endTime - startTime.get();
            numTasks.incrementAndGet();
            totalTime.addAndGet(taskTime);
            LOGGER.fine(String.format("Thread %s: end %s, time= %dns", t, r, taskTime));
        } finally {
            super.afterExecute(r, t);
        }

    }

    @Override
    protected void terminated() {
        try {
            LOGGER.info(String.format("Terminated: avg time=%dns", totalTime.get() / numTasks.get()));
        } finally {
            super.terminated();
        }
    }
}