一种有回调的ThreadPool的实现方式

直接上源码



import android.util.Log;
import java.util.concurrent.Executor;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPool {
    @SuppressWarnings("unused")
    private static final String TAG = "ThreadPool";
    private static final int CORE_POOL_SIZE = 4;
    private static final int MAX_POOL_SIZE = 8;
    private static final int KEEP_ALIVE_TIME = 10; // 10 seconds

    // Resource type
    public static final int MODE_NONE = 0;
    public static final int MODE_CPU = 1;
    public static final int MODE_NETWORK = 2;

    public static final JobContext JOB_CONTEXT_STUB = new JobContextStub();

    ResourceCounter mCpuCounter = new ResourceCounter(2);
    ResourceCounter mNetworkCounter = new ResourceCounter(2);

    // A Job is like a Callable, but it has an addition JobContext parameter.
    public interface Job<T> {
        public T run(JobContext jc);
    }

    public interface JobContext {
        boolean isCancelled();
        void setCancelListener(CancelListener listener);
        boolean setMode(int mode);
    }

    private static class JobContextStub implements JobContext {
        @Override
        public boolean isCancelled() {
            return false;
        }

        @Override
        public void setCancelListener(CancelListener listener) {
        }

        @Override
        public boolean setMode(int mode) {
            return true;
        }
    }

    public interface CancelListener {
        public void onCancel();
    }

    private static class ResourceCounter {
        public int value;
        public ResourceCounter(int v) {
            value = v;
        }
    }

    private final Executor mExecutor;

    public ThreadPool() {
        this(CORE_POOL_SIZE, MAX_POOL_SIZE);
    }

    public ThreadPool(int initPoolSize, int maxPoolSize) {
        mExecutor = new ThreadPoolExecutor(
                initPoolSize, maxPoolSize, KEEP_ALIVE_TIME,
                TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(),
                new PriorityThreadFactory("thread-pool",
                android.os.Process.THREAD_PRIORITY_BACKGROUND));
    }

    // Submit a job to the thread pool. The listener will be called when the
    // job is finished (or cancelled).
    public <T> Future<T> submit(Job<T> job, FutureListener<T> listener) {
        Worker<T> w = new Worker<T>(job, listener);
        mExecutor.execute(w);
        return w;
    }

    public <T> Future<T> submit(Job<T> job) {
        return submit(job, null);
    }

    private class Worker<T> implements Runnable, Future<T>, JobContext {
        @SuppressWarnings("hiding")
        private static final String TAG = "Worker";
        private Job<T> mJob;
        private FutureListener<T> mListener;
        private CancelListener mCancelListener;
        private ResourceCounter mWaitOnResource;
        private volatile boolean mIsCancelled;
        private boolean mIsDone;
        private T mResult;
        private int mMode;

        public Worker(Job<T> job, FutureListener<T> listener) {
            mJob = job;
            mListener = listener;
        }

        // This is called by a thread in the thread pool.
        @Override
        public void run() {
            T result = null;

            // A job is in CPU mode by default. setMode returns false
            // if the job is cancelled.
            if (setMode(MODE_CPU)) {
                try {
                    result = mJob.run(this);
                } catch (Throwable ex) {
                    Log.w(TAG, "Exception in running a job", ex);
                }
            }

            synchronized(this) {
                setMode(MODE_NONE);
                mResult = result;
                mIsDone = true;
                notifyAll();
            }
            if (mListener != null) mListener.onFutureDone(this);
        }

        // Below are the methods for Future.
        @Override
        public synchronized void cancel() {
            if (mIsCancelled) return;
            mIsCancelled = true;
            if (mWaitOnResource != null) {
                synchronized (mWaitOnResource) {
                    mWaitOnResource.notifyAll();
                }
            }
            if (mCancelListener != null) {
                mCancelListener.onCancel();
            }
        }

        @Override
        public boolean isCancelled() {
            return mIsCancelled;
        }

        @Override
        public synchronized boolean isDone() {
            return mIsDone;
        }

        @Override
        public synchronized T get() {
            while (!mIsDone) {
                try {
                    wait();
                } catch (Exception ex) {
                    Log.w(TAG, "ingore exception", ex);
                    // ignore.
                }
            }
            return mResult;
        }

        @Override
        public void waitDone() {
            get();
        }

        // Below are the methods for JobContext (only called from the
        // thread running the job)
        @Override
        public synchronized void setCancelListener(CancelListener listener) {
            mCancelListener = listener;
            if (mIsCancelled && mCancelListener != null) {
                mCancelListener.onCancel();
            }
        }

        @Override
        public boolean setMode(int mode) {
            // Release old resource
            ResourceCounter rc = modeToCounter(mMode);
            if (rc != null) releaseResource(rc);
            mMode = MODE_NONE;

            // Acquire new resource
            rc = modeToCounter(mode);
            if (rc != null) {
                if (!acquireResource(rc)) {
                    return false;
                }
                mMode = mode;
            }

            return true;
        }

        private ResourceCounter modeToCounter(int mode) {
            if (mode == MODE_CPU) {
                return mCpuCounter;
            } else if (mode == MODE_NETWORK) {
                return mNetworkCounter;
            } else {
                return null;
            }
        }

        private boolean acquireResource(ResourceCounter counter) {
            while (true) {
                synchronized (this) {
                    if (mIsCancelled) {
                        mWaitOnResource = null;
                        return false;
                    }
                    mWaitOnResource = counter;
                }

                synchronized (counter) {
                    if (counter.value > 0) {
                        counter.value--;
                        break;
                    } else {
                        try {
                            counter.wait();
                        } catch (InterruptedException ex) {
                            // ignore.
                        }
                    }
                }
            }

            synchronized (this) {
                mWaitOnResource = null;
            }

            return true;
        }

        private void releaseResource(ResourceCounter counter) {
            synchronized (counter) {
                counter.value++;
                counter.notifyAll();
            }
        }
    }
}

最后编辑于
©著作权归作者所有,转载或内容合作请联系作者
  • 序言:七十年代末,一起剥皮案震惊了整个滨河市,随后出现的几起案子,更是在滨河造成了极大的恐慌,老刑警刘岩,带你破解...
    沈念sama阅读 211,743评论 6 492
  • 序言:滨河连续发生了三起死亡事件,死亡现场离奇诡异,居然都是意外死亡,警方通过查阅死者的电脑和手机,发现死者居然都...
    沈念sama阅读 90,296评论 3 385
  • 文/潘晓璐 我一进店门,熙熙楼的掌柜王于贵愁眉苦脸地迎上来,“玉大人,你说我怎么就摊上这事。” “怎么了?”我有些...
    开封第一讲书人阅读 157,285评论 0 348
  • 文/不坏的土叔 我叫张陵,是天一观的道长。 经常有香客问我,道长,这世上最难降的妖魔是什么? 我笑而不...
    开封第一讲书人阅读 56,485评论 1 283
  • 正文 为了忘掉前任,我火速办了婚礼,结果婚礼上,老公的妹妹穿的比我还像新娘。我一直安慰自己,他们只是感情好,可当我...
    茶点故事阅读 65,581评论 6 386
  • 文/花漫 我一把揭开白布。 她就那样静静地躺着,像睡着了一般。 火红的嫁衣衬着肌肤如雪。 梳的纹丝不乱的头发上,一...
    开封第一讲书人阅读 49,821评论 1 290
  • 那天,我揣着相机与录音,去河边找鬼。 笑死,一个胖子当着我的面吹牛,可吹牛的内容都是我干的。 我是一名探鬼主播,决...
    沈念sama阅读 38,960评论 3 408
  • 文/苍兰香墨 我猛地睁开眼,长吁一口气:“原来是场噩梦啊……” “哼!你这毒妇竟也来了?” 一声冷哼从身侧响起,我...
    开封第一讲书人阅读 37,719评论 0 266
  • 序言:老挝万荣一对情侣失踪,失踪者是张志新(化名)和其女友刘颖,没想到半个月后,有当地人在树林里发现了一具尸体,经...
    沈念sama阅读 44,186评论 1 303
  • 正文 独居荒郊野岭守林人离奇死亡,尸身上长有42处带血的脓包…… 初始之章·张勋 以下内容为张勋视角 年9月15日...
    茶点故事阅读 36,516评论 2 327
  • 正文 我和宋清朗相恋三年,在试婚纱的时候发现自己被绿了。 大学时的朋友给我发了我未婚夫和他白月光在一起吃饭的照片。...
    茶点故事阅读 38,650评论 1 340
  • 序言:一个原本活蹦乱跳的男人离奇死亡,死状恐怖,灵堂内的尸体忽然破棺而出,到底是诈尸还是另有隐情,我是刑警宁泽,带...
    沈念sama阅读 34,329评论 4 330
  • 正文 年R本政府宣布,位于F岛的核电站,受9级特大地震影响,放射性物质发生泄漏。R本人自食恶果不足惜,却给世界环境...
    茶点故事阅读 39,936评论 3 313
  • 文/蒙蒙 一、第九天 我趴在偏房一处隐蔽的房顶上张望。 院中可真热闹,春花似锦、人声如沸。这庄子的主人今日做“春日...
    开封第一讲书人阅读 30,757评论 0 21
  • 文/苍兰香墨 我抬头看了看天上的太阳。三九已至,却和暖如春,着一层夹袄步出监牢的瞬间,已是汗流浃背。 一阵脚步声响...
    开封第一讲书人阅读 31,991评论 1 266
  • 我被黑心中介骗来泰国打工, 没想到刚下飞机就差点儿被人妖公主榨干…… 1. 我叫王不留,地道东北人。 一个月前我还...
    沈念sama阅读 46,370评论 2 360
  • 正文 我出身青楼,却偏偏与公主长得像,于是被迫代替她去往敌国和亲。 传闻我的和亲对象是个残疾皇子,可洞房花烛夜当晚...
    茶点故事阅读 43,527评论 2 349

推荐阅读更多精彩内容