{"id":2208,"date":"2022-07-24T23:24:53","date_gmt":"2022-07-24T15:24:53","guid":{"rendered":"http:\/\/47.101.202.111\/?p=2208"},"modified":"2022-07-24T23:35:01","modified_gmt":"2022-07-24T15:35:01","slug":"%e5%b9%b6%e5%8f%91%e5%b7%a5%e5%85%b7%e7%b1%bb-%e7%ba%bf%e7%a8%8b%e5%90%8c%e6%ad%a5%e5%92%8c%e6%8e%a7%e5%88%b6","status":"publish","type":"post","link":"http:\/\/139.196.114.170\/?p=2208","title":{"rendered":"\u5e76\u53d1\u5de5\u5177\u7c7b &#8211; \u7ebf\u7a0b\u540c\u6b65\u548c\u63a7\u5236"},"content":{"rendered":"<h4>Semaphore<\/h4>\n<ul>\n<li>\u5e94\u7528\n<ul>\n<li>\u9650\u5236\u8bbf\u95ee\u5171\u4eab\u8d44\u6e90\u7684\u7ebf\u7a0b\u6570\u76ee<\/li>\n<\/ul>\n<\/li>\n<li>\u539f\u7406\u8bf4\u660e\n<ul>\n<li>\u5171\u4eab\u8d44\u6e90\u6c60\u6709permits\u4e2a\u95e8\u7968\uff08\u5047\u5b9apermits\u53ea\u5141\u8bb8\u9010\u4e2a\u7533\u8bf7\u9010\u4e2a\u5f52\u8fd8\uff09\uff0c\u6bcf\u7533\u8bf7\u95e8\u7968\u65f6permits&#8211;\uff0cpermits\uff1c0\u65e0\u76c8\u4f59\u51c6\u5165\u8d44\u683c\uff0c\u6b64\u65f6\u7533\u8bf7\u7ebf\u7a0b\u8fdb\u5165permits\u7684\u963b\u585e\u961f\u5217\uff0c|permits|\u5373\u963b\u585e\u961f\u5217\u4e2d\u7ebf\u7a0b\u7684\u6570\u91cf\u3002\u6bcf\u5f52\u8fd8\u95e8\u7968\u65f6permits++\uff0cpermits\u22640\u6709\u7ebf\u7a0b\u6b63\u5728\u7b49\u5f85\uff0c\u6b64\u65f6\u5524\u9192\u963b\u585e\u961f\u5217\u4e2d\u7684\u7b49\u5f85\u7ebf\u7a0b\u83b7\u53d6\u6b64\u6b21\u5f52\u8fd8\u7684\u51c6\u5165\u8d44\u683c<\/li>\n<\/ul>\n<\/li>\n<li>\u6784\u9020\u51fd\u6570<\/li>\n<\/ul>\n<pre lang=\"java\">\nSemaphore(int permits) \u6307\u5b9a\u51c6\u5165\u8d44\u683c\u6570\u91cf\uff0c\u9ed8\u8ba4\u975e\u516c\u5e73\u9501\nSemaphore(int permits, boolean fair) \u6307\u5b9a\u51c6\u5165\u8d44\u683c\u6570\u91cf\uff0c\u53ef\u6307\u5b9a\u516c\u5e73\u9501\n<\/pre>\n<ul>\n<li>\u5e38\u7528API<\/li>\n<\/ul>\n<pre lang=\"java\">\nvoid acquire() \u7533\u8bf7\u51c6\u5165\u8d44\u683c\uff0c\u65e0\u53ef\u7528\u5219\u963b\u585e\uff0c\u76f4\u5230\u6709\u53ef\u7528\u8d44\u6e90\u6216\u7ebf\u7a0b\u88ab\u6253\u65ad\u88ab\u5524\u9192\nvoid release() \u5f52\u8fd8\u51c6\u5165\u8d44\u683c\uff0c\u82e5\u6709\u5219\u5524\u9192\u963b\u585e\u961f\u5217\u4e2d\u7684\u7b49\u5f85\u7ebf\u7a0b\n<\/pre>\n<ul>\n<li>\u4f7f\u7528\u65b9\u6cd5<\/li>\n<\/ul>\n<pre><code class=\"language-java \">private static final int NUM = 100;\nprivate static final Semaphore sem = new Semaphore(NUM);\ntry{\n    sem.acquire();\n    \/\/\u8d44\u6e90\u6c60\u7ebf\u7a0b\u5b89\u5168\u7684\u539f\u5b50\u53d6\u64cd\u4f5c\n}catch(InterruptedExceptione){\n    e.printStackTrace();\n}finally{\n    \/\/\u8d44\u6e90\u6c60\u7ebf\u7a0b\u5b89\u5168\u7684\u539f\u5b50\u5f52\u8fd8\u64cd\u4f5c\n    sem.release();\n}\n<\/code><\/pre>\n<ul>\n<li>\u6ce8\u610f\u4e8b\u9879\n<ul>\n<li>\u4f7f\u7528\u4fe1\u53f7\u91cf\u65f6\u5141\u8bb8\u591a\u4e2a\u7ebf\u7a0b\u8bbf\u95ee\u5171\u4eab\u8d44\u6e90\uff0c\u5f88\u53ef\u80fd\u5bfc\u81f4\u5e76\u53d1\u95ee\u9898\uff0c\u6240\u4ee5\u5e94\u786e\u4fdd\u5bf9\u5171\u4eab\u8d44\u6e90\u7ebf\u7a0b\u5b89\u5168\u7684\u539f\u5b50\u64cd\u4f5c<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h4>CountDownLatch<\/h4>\n<ul>\n<li>\u5e94\u7528\n<ul>\n<li>\u63a7\u5236\u4e00\u7ec4\u7ebf\u7a0b\u540c\u6b65\u8fdb\u5ea6\uff0c\u7b49\u5f85\u6240\u6709\u7ebf\u7a0b\u90fd\u6267\u884c\u5b8c\u6bd5\u624d\u7ee7\u7eed\u5411\u4e0b\u6267\u884c\uff0c\u5e38\u7528\u4e8e\u5e76\u884c\u8ba1\u7b97\u7684\u5212\u5206\u548c\u6574\u5408<\/li>\n<li>\u63a7\u5236\u67d0\u4e2a\u7ebf\u7a0b\u64cd\u4f5cN\u6b21\u540e\u7ee7\u7eed\u5411\u4e0b\u6267\u884c<\/li>\n<\/ul>\n<\/li>\n<li>\u539f\u7406\u8bf4\u660e\n<ul>\n<li>\u521d\u59cb\u9700\u8981\u540c\u6b65\u8fdb\u5ea6\u7684\u7ebf\u7a0b\u6570count\u3002\u6bcf\u4e2a\u7ebf\u7a0b\u6267\u884c\u5b8c\u81ea\u5df1\u7684\u903b\u8f91\u540ecount&#8211;\uff0c\u5148\u6267\u884c\u5b8c\u7684\u7ebf\u7a0bcount\u22600\uff0c\u8bf4\u660e\u6709\u5176\u4ed6\u7ebf\u7a0b\u672a\u6267\u884c\u5b8c\u6bd5\uff0c\u539f\u5730\u963b\u585e\u7b49\u5f85\u3002\u76f4\u5230\u6240\u6709\u7ebf\u7a0b\u6267\u884c\u5b8c\u6bd5count=0\uff0c\u6b64\u65f6\u5524\u9192\u6240\u6709\u5176\u4ed6\u7ebf\u7a0b\u7ee7\u7eed\u5411\u4e0b\u6267\u884c<\/li>\n<\/ul>\n<\/li>\n<li>\u6784\u9020\u51fd\u6570<\/li>\n<\/ul>\n<pre lang=\"java\">\nCountDownLatch(int count)\n<\/pre>\n<ul>\n<li>\u5e38\u7528API<\/li>\n<\/ul>\n<pre lang=\"java\">\nvoid countdown() \u6267\u884c\u81ea\u51cf\uff0c\u52300\u540e\u5524\u9192\u6240\u6709\u7b49\u5f85\u7ebf\u7a0b\nvoid await() \u5f53\u524d\u7ebf\u7a0b\u7b49\u5f85\u8fdb\u5ea6\u52300\n<\/pre>\n<ul>\n<li>\u4f7f\u7528\u65b9\u6cd5\n<ul>\n<li>\u5b98\u65b9\u6848\u4f8b\u4f7f\u7528\u4e24\u4e2aCDL\u6765\u76f8\u4e92\u540c\u6b65\u7b49\u5f85\uff1a\u6240\u6709worker\u9700\u8981\u7b49\u5f85driver\u6267\u884c\u5b8cdoPrepare()\u540e\u624d\u53ef\u6267\u884c\uff0cdriver\u9700\u8981\u7b49\u5f85\u6240\u6709worker\u6267\u884c\u5b8c\u6bd5\u624d\u53ef\u7ee7\u7eed\u5411\u4e0b\u6267\u884cdoCollect()<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre><code class=\"language-java \">classDriver{\n    void main() throws InterruptedException{\n        CountDownLatch startSignal = new CountDownLatch(1);\n        CountDownLatch doneSignal = new CountDownLatch(N);\n        for(int i=0; i&lt;N; ++i)\n            new Thread(new Worker(startSignal, doneSignal)).start();\n        doPrepare();\n        startSignal.countDown();\n        doSomethingElse();\n        doneSignal.await();\n        doCollect();\n    }\n}\nclass Worker implements Runnable{\n    private final CountDownLatch startSignal;\n    private final CountDownLatch doneSignal;\n    Worker(CountDownLatch startSignal, CountDownLatch doneSignal){\n        this.startSignal = startSignal;\n        this.doneSignal = doneSignal;\n    }\n    public void run(){\n        try{\n        startSignal.await();\n        doWork();\n        doneSignal.countDown();\n        }catch(InterruptedException ex){...}\n    }\n    void doWork(){...}\n}\n<\/code><\/pre>\n<ul>\n<li>\u6ce8\u610f\u4e8b\u9879\n<ul>\n<li>\u6bcf\u6b21\u4f7f\u7528CDL\u9700\u8981\u91cd\u7f6e\u521d\u59cb\u503c<\/li>\n<li>\u4efb\u4e00\u7ebf\u7a0b\u5728await()\u8fc7\u7a0b\u4e2d\u8bbe\u7f6einterrupt\u6807\u5fd7\u6216\u88ab\u5176\u4ed6\u7ebf\u7a0b\u6253\u65ad\u629b\u51faInterruptedException\uff0c\u6b64\u65f6\u5fc5\u987b\u7ec8\u6b62CountDownLatch\u8fc7\u7a0b\uff0c\u5426\u5219\u5176\u4ed6\u7ebf\u7a0b\u5c06\u4e00\u76f4\u7b49\u5f85\u4e0b\u53bb<\/li>\n<li>countdown()\u8c03\u7528happen-before\u4e8eawait()\u8c03\u7528<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h4>CyclicBarrier<\/h4>\n<ul>\n<li>\u5e94\u7528\u548c\u539f\u7406\n<ul>\n<li>\u540cCountDownLatch<\/li>\n<\/ul>\n<\/li>\n<li>\u6784\u9020\u51fd\u6570<\/li>\n<\/ul>\n<pre lang=\"java\">\nCyclicBarrier(int parties) parties\u4e2a\u7ebf\u7a0b\u7b49\u5f85\u5b9e\u4f8b\u65f6\u653e\u884c\u5404\u7ebf\u7a0b\u7ee7\u7eed\u5411\u4e0b\u6267\u884c\uff0c\u5e76\u5f00\u542f\u65b0\u4e00\u8f6e\u8ba1\u6570\u7b49\u5f85\nCyclicBarrier(int parties, Runnable barrierAction) parties\u4e2a\u7ebf\u7a0b\u7b49\u5f85\u5b9e\u4f8b\u65f6\uff0c\u7531\u6700\u540e\u4e00\u4e2a\u8fdb\u5165barrier\u5b9e\u4f8b\u7684\u7ebf\u7a0b\u540c\u6b65\u6267\u884cbarrierAction\u51fd\u6570\uff0c\u51fd\u6570\u6267\u884c\u5b8c\u6bd5\u653e\u884c\u5404\u7ebf\u7a0b\u7ee7\u7eed\u5411\u4e0b\u6267\u884c\uff0c\u5e76\u5f00\u542f\u65b0\u4e00\u8f6e\u8ba1\u6570\u7b49\u5f85\n<\/pre>\n<ul>\n<li>\u5e38\u7528API<\/li>\n<\/ul>\n<pre lang=\"java\">\nint await() \u5f53\u524d\u7ebf\u7a0b\u5904\u4e8e\u7b49\u5f85\u72b6\u6001\uff0c\u76f4\u5230\u6240\u6709\u7ebf\u7a0b\u90fd\u5904\u4e8e\u7b49\u5f85\u72b6\u6001\u653e\u884c\u3002\u5012\u5e8f\u8fd4\u56de\u7d22\u5f15\u663e\u793a\u5f53\u524d\u8fdb\u5ea6\uff0c\u53ef\u6307\u5b9a\u6267\u884c\u5230\u67d0\u8fdb\u5ea6\u7684\u7ebf\u7a0b\u6253\u5370\u4fe1\u606f\u6216\u6267\u884c\u4e0d\u4f9d\u8d56\u5404\u7ebf\u7a0b\u7684barrierAction\u51fd\u6570<\/pre>\n<ul>\n<li>\u4f7f\u7528\u65b9\u6cd5\n<ul>\n<li>\u5b98\u65b9\u6848\u4f8b\u5c55\u73b0\u4e86\u4e00\u4e2a\u53ef\u5212\u5206\u7684\u5e76\u884c\u4efb\u52a1\uff1aN\u4e2a\u7ebf\u7a0b\u5e76\u884c\uff0c\u5404\u81ea\u5904\u7406\u5404\u81ea\u7684\u77e9\u9635\u884c\u3002\u5f53\u4e14\u4ec5\u5f53\u6240\u6709\u7ebf\u7a0b\u6267\u884c\u5b8c\u6bd5\u65f6\uff0c\u7531\u6700\u540e\u4e00\u4e2a\u8fdb\u5165barrier\u7684\u7ebf\u7a0b\u6267\u884cmergeRows()\u5408\u5e76N\u4e2a\u7ebf\u7a0b\u7684\u8ba1\u7b97\u7ed3\u679c\uff0c\u5408\u5e76\u5b8c\u6bd5\u540e\u6539\u53d8done()\u8fd4\u56de\u503c\uff0c\u5e76\u653e\u884c\u5404\u7ebf\u7a0b\u7ee7\u7eed\u5411\u4e0b\u6267\u884c\u3002\u5404\u7ebf\u7a0b\u7ee7\u7eed\u5faa\u73af\u65f6done()\u9000\u51fa\u5faa\u73af\uff0c\u7b49\u5230\u6240\u6709\u7ebf\u7a0b\u6267\u884c\u5b8c\u6bd5\u540e\u7ec8\u6b62<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre><code class=\"language-java \">class Solver {\n    final int N;\n    final float[][] data;\n    final CyclicBarrier barrier;\n    public Solver(float[][] matrix) {\n        data = matrix;\n        N = matrix.length;\n        Runnable barrierAction = () -&gt; mergeRows(...);\n        barrier = new CyclicBarrier(N, barrierAction);\n        List&lt;Thread&gt; threads = new ArrayList&lt;&gt;(N);\n        for (int i = 0; i &lt; N; i++) {\n            Thread thread = new Thread(new Worker(i));\n            threads.add(thread);\n            thread.start();\n        }\n        for (Thread thread : threads)\n            thread.join();\n    }\n\n    class Worker implements Runnable {\n        int myRow;\n        Worker(int row) {\n            myRow = row;\n        }\n        public void run() {\n            while (!done()) {\n                processRow(myRow);\n                try {\n                    barrier.await();\n                } catch (InterruptedException ex) {\n                    return;\n                } catch (BrokenBarrierException ex) {\n                    return;\n                }\n            }\n        }\n    }\n}\n<\/code><\/pre>\n<ul>\n<li>\u6ce8\u610f\u4e8b\u9879\n<ul>\n<li>CyclicBarrier\u6bcf\u6b21\u653e\u884c\u540e\u81ea\u52a8\u91cd\u7f6e\u8ba1\u6570\u4e3a\u521d\u59cb\u503cparties<\/li>\n<li>\u5982\u679c\u4e00\u4e2a\u7ebf\u7a0b\u5728await()\u65f6\u53d1\u751f\u4e2d\u65adInterruptedException,\u6545\u969cBrokenBarrierException,\u8d85\u65f6TimeoutException\uff0c\u5176\u4ed6\u6240\u6709await()\u7ebf\u7a0b\u90fd\u5c06\u89e6\u53d1\u76f8\u5e94\u5f02\u5e38<\/li>\n<li>\u5404\u7ebf\u7a0b\u903b\u8f91happen-before\u4e8eawait()\u8c03\u7528<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h4>CountDownLatch\u548cCyclicBarrier\u6bd4\u8f83<\/h4>\n<ul>\n<li>\u76f8\u540c\u70b9\n<ul>\n<li>\u8ba1\u6570\u539f\u7406\u76f8\u540c\uff0c\u90fd\u53ef\u7528\u4e8e\u7ebf\u7a0b\u4e4b\u95f4\u7684\u7b49\u5f85\u4ee5\u8fbe\u5230\u6b65\u8c03\u4e00\u81f4<\/li>\n<\/ul>\n<\/li>\n<li>\u4e0d\u540c\u70b9\n<ul>\n<li>CDL\u653e\u884c\u540e\u8ba1\u6570\u4e0d\u91cd\u7f6e\uff0cCB\u653e\u884c\u540e\u8ba1\u6570\u81ea\u52a8\u91cd\u7f6e<\/li>\n<li>\u4f7f\u7528\u573a\u666f\uff0cCDL\u66f4\u591a\u7528\u4e8e\u4e00\u4e2a\u7ebf\u7a0b\u7b49\u591a\u4e2a\u7ebf\u7a0b\uff0cCB\u591a\u7528\u4e8e\u7ebf\u7a0b\u4e4b\u95f4\u76f8\u4e92\u7b49\u5f85<\/li>\n<li>\u56de\u8c03\u51fd\u6570\uff0cCB\u53ef\u4ee5\u5728\u6b65\u8c03\u4e00\u81f4\u540e\u6267\u884c\u4e00\u4e2a\u56de\u8c03\u51fd\u6570\uff0cCDL\u65e0<\/li>\n<li>await\u8fd4\u56de\u503c\uff0cCDL\u65e0\u8fdb\u5ea6\u8fd4\u56de\u503c\uff0cCB\u63d0\u4f9b\u4e86\u8fdb\u5ea6\u8fd4\u56de\u503c<\/li>\n<li>\u5f02\u5e38\u5904\u7406\u673a\u5236\uff0cCDL\u4ec5\u5728\u7ebf\u7a0bawait()\u65f6\u89e6\u53d1InterruptedException\uff0c\u4e14\u4e2d\u65ad\u82e5\u4e0d\u5904\u7406\u5176\u4ed6\u7ebf\u7a0b\u5c06\u6c38\u8fdc\u7b49\u4e0b\u53bb\uff1bCB\u53ea\u8981\u6709\u4e00\u4e2a\u7ebf\u7a0b\u53d1\u751f\u4e2d\u65ad\u3001\u8d85\u65f6\u3001\u6545\u969c\u5c06\u629b\u51fa\u5bf9\u5e94\u7684\u5f02\u5e38\u5e76\u7ed3\u675f\u7b49\u5f85\u8fc7\u7a0b<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h5>\u53c2\u8003\u8d44\u6599<\/h5>\n<p><a href=\"https:\/\/docs.oracle.com\/en\/java\/javase\/11\/docs\/api\/java.base\/java\/util\/concurrent\/CountDownLatch.html\">CountDownLatch(JavaSE11&amp;JDK11)<\/a><br \/>\n<a href=\"https:\/\/docs.oracle.com\/en\/java\/javase\/11\/docs\/api\/java.base\/java\/util\/concurrent\/CyclicBarrier.html\">CyclicBarrier(JavaSE11&amp;JDK11)<\/a><br \/>\n<a href=\"https:\/\/docs.oracle.com\/en\/java\/javase\/11\/docs\/api\/java.base\/java\/util\/concurrent\/Semaphore.html\">Semaphore(JavaSE11&amp;JDK11)<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Semaphore \u5e94\u7528 \u9650\u5236\u8bbf\u95ee\u5171\u4eab\u8d44\u6e90\u7684\u7ebf\u7a0b\u6570\u76ee \u539f\u7406\u8bf4\u660e \u5171\u4eab\u8d44\u6e90\u6c60\u6709permits\u4e2a\u95e8\u7968\uff08\u5047\u5b9aperm &hellip; <\/p>\n<p class=\"link-more\"><a href=\"http:\/\/139.196.114.170\/?p=2208\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb<span class=\"screen-reader-text\">\u201c\u5e76\u53d1\u5de5\u5177\u7c7b &#8211; \u7ebf\u7a0b\u540c\u6b65\u548c\u63a7\u5236\u201d<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[25],"tags":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts\/2208"}],"collection":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2208"}],"version-history":[{"count":4,"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts\/2208\/revisions"}],"predecessor-version":[{"id":2212,"href":"http:\/\/139.196.114.170\/index.php?rest_route=\/wp\/v2\/posts\/2208\/revisions\/2212"}],"wp:attachment":[{"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2208"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/139.196.114.170\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}