AQS (AbstractQueuedSynchronizer),\u62bd\u8c61\u961f\u5217\u540c\u6b65\u5668\u3002
\nAQS\u7684\u540c\u6b65\u72b6\u6001
\nAQS\u4f7f\u7528\u4e00\u4e2aint\u6210\u5458\u53d8\u91cf\u6765\u8868\u793a\u540c\u6b65\u72b6\u6001\uff0c\u901a\u8fc7\u5185\u7f6e\u7684FIFO\u961f\u5217\u6765\u5b8c\u6210\u83b7\u53d6\u8d44\u6e90\u7ebf\u7a0b\u7684\u6392\u961f\u5de5\u4f5c\u3002AQS\u4f7f\u7528CAS\u5bf9\u8be5\u540c\u6b65\u72b6\u6001\u8fdb\u884c\u539f\u5b50\u64cd\u4f5c\u5b9e\u73b0\u5bf9\u5176\u503c\u7684\u4fee\u6539\u3002
\nprivate volatile int state;\/\/\u5171\u4eab\u53d8\u91cf\uff0c\u4f7f\u7528volatile\u4fee\u9970\u4fdd\u8bc1\u7ebf\u7a0b\u53ef\u89c1\u6027
\n\u72b6\u6001\u4fe1\u606f\u901a\u8fc7getState, setState, compareAndSetState\u65b9\u6cd5\u8fdb\u884c\u64cd\u4f5c
\n\/\/\u8fd4\u56de\u540c\u6b65\u72b6\u6001\u7684\u5f53\u524d\u503c
\nprotected final int getState() {
\nreturn state;
\n}
\n\/\/\u8bbe\u7f6e\u540c\u6b65\u72b6\u6001\u7684\u503c
\nprotected final void setState(intnewState) {
\nstate = newState;
\n}
\n\/\/\u539f\u5b50\u5730(CAS\u64cd\u4f5c)\u5c06\u540c\u6b65\u72b6\u6001\u503c\u8bbe\u7f6e\u4e3a\u7ed9\u5b9a\u503cupdate\u5982\u679c\u5f53\u524d\u540c\u6b65\u72b6\u6001\u7684\u503c\u7b49\u4e8eexpect (\u671f\u671b\u503c)
\nprotected final boolean compareAndSetState(intexpect, intupdate){
\nreturnunsafe.compareAndSwapInt(this, stateOffset, expect, update);
\n}
\nAQS\u5185\u90e8\u7684\u540c\u6b65\u961f\u5217
\n1\u3001\t\u540c\u6b65\u5668AQS\u5185\u90e8\u7684\u5b9e\u73b0\u662f\u4f9d\u8d56\u540c\u6b65\u961f\u5217(\u53cc\u5411\u961f\u5217)\u6765\u5b8c\u6210\u540c\u6b65\u72b6\u6001\u7684\u7ba1\u7406\u3002
\n2\u3001\t\u5f53\u524d\u7ebf\u7a0b\u83b7\u53d6\u8d44\u6e90\u5931\u8d25\u65f6\uff0c\u540c\u6b65\u5668AQS\u4f1a\u5c06\u5f53\u524d\u7ebf\u7a0b\u548c\u7b49\u5f85\u72b6\u6001\u7b49\u4fe1\u606f\u6784\u9020\u6210\u4e3a\u4e00\u4e2a\u8282\u70b9 (Node)\u52a0\u5165\u5230\u540c\u6b65\u961f\u5217\uff0c\u540c\u65f6\u4f1a\u963b\u585e\u5f53\u524d\u7ebf\u7a0b;
\n3\u3001\t\u5f53\u540c\u6b65\u72b6\u6001\u91ca\u653e\u7684\u65f6\u5019\uff0c\u4f1a\u628a\u961f\u5217\u9996\u8282\u70b9(\u6216\u8005\u5176\u4ed6\u8282\u70b9\uff0c\u53d6\u51b3\u4e8e\u662f\u5426\u662f\u516c\u5e73\u9501)\u4e2d\u7684\u7ebf \u7a0b\u5524\u9192\uff0c\u4f7f\u9996\u8282\u70b9\u7684\u7ebf\u7a0b\u518d\u6b21\u5c1d\u8bd5\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u3002
\n4\u3001\t\u8282\u70b9\u7684\u4e3b\u8981\u72b6\u6001\u6709\uff1awaitStatus\uff1a\u7b49\u5f85\u72b6\u6001;prev\uff1a\u524d\u9a71\u8282\u70b9;next\uff1a\u540e\u7ee7\u8282\u70b9;thread\uff1a\u5f53\u524d\u8282\u70b9\u4ee3\u8868\u7684\u7ebf\u7a0b\u3002
\n5\u3001\tNode\u52a0\u5165\u961f\u5217\u5c3e\u90e8\u7684\u8fc7\u7a0b\u8981\u4fdd\u8bc1\u7ebf\u7a0b\u7684\u5b89\u5168\uff0c\u5426\u5219\u5728\u591a\u7ebf\u7a0b\u7684\u73af\u5883\u4e0b\uff0c\u53ef\u80fd\u9020\u6210\u6dfb\u52a0\u5230 \u961f\u5217\u7b49\u5f85\u7684\u8282\u70b9\u987a\u5e8f\u9519\u8bef\uff0c\u6216\u8005\u6570\u91cf\u4e0d\u5bf9\u3002\u56e0\u6b64\u540c\u6b65\u5668\u63d0\u4f9b\u4e86 CAS\u64cd\u4f5c\uff0c\u539f\u5b50\u7684\u8bbe\u7f6e\u5c3e\u8282\u70b9(\u4fdd \u8bc1\u4e00\u4e2a\u672a\u83b7\u53d6\u5230\u540c\u6b65\u72b6\u6001\u7684\u7ebf\u7a0b\u52a0\u5165\u5230\u540c\u6b65\u961f\u5217\u540e\uff0c\u4e0b\u4e00\u4e2a\u672a\u83b7\u53d6\u7684\u7ebf\u7a0b\u624d\u80fd\u591f\u52a0\u5165)\u3002
\nAQS\u5b9a\u4e49\u4e24\u79cd\u8d44\u6e90\u5171\u4eab\u65b9\u5f0f
\nExclusive (\u72ec\u5360)\uff1a\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u80fd\u6267\u884c\uff0c\u5982ReentrantLock\u3002\u53c8\u53ef\u5206\u4e3a\u516c\u5e73\u9501\u548c\u975e\u516c\u5e73\u9501:
\n1\u3001\t\u516c\u5e73\u9501\uff1a\u6309\u7167\u7ebf\u7a0b\u5728\u961f\u5217\u4e2d\u7684\u6392\u961f\u987a\u5e8f\uff0c\u5148\u5230\u8005\u5148\u62ff\u5230\u9501
\n2\u3001\t\u975e\u516c\u5e73\u9501\uff1a\u5f53\u7ebf\u7a0b\u8981\u83b7\u53d6\u9501\u65f6\uff0c\u65e0\u89c6\u961f\u5217\u987a\u5e8f\u76f4\u63a5\u53bb\u62a2\u9501\uff0c\u8c01\u62a2\u5230\u5c31\u662f\u8c01\u7684
\nShare (\u5171\u4eab)\uff1a\u591a\u4e2a\u7ebf\u7a0b\u53ef\u540c\u65f6\u6267\u884c\uff0c\u5982 Semaphore\/CountDownLatch\u3002 Semaphore\u3001CountDownLatCh\u3001CyclicBarrier\u3001 ReadWriteLock \u6211\u4eec\u90fd\u4f1a\u5728\u540e\u9762\u8bb2\u5230\u3002
\nAQS\u4f7f\u7528\u4e86\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\uff0c\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u65f6\u9700\u8981\u91cd\u5199\u4e0b\u9762\u51e0\u4e2aAQS\u63d0\u4f9b\u7684\u6a21\u677f\u65b9\u6cd5\uff1a
\nisHeldExclusively()\/\/\u8be5\u7ebf\u7a0b\u662f\u5426\u6b63\u5728\u72ec\u5360\u8d44\u6e90\u3002\u53ea\u6709\u7528\u5230condition\u624d\u9700\u8981\u53bb\u5b9e\u73b0\u5b83\u3002
\ntryAcquire(int)\/\/\u72ec\u5360\u65b9\u5f0f\u3002\u5c1d\u8bd5\u83b7\u53d6\u8d44\u6e90\uff0c\u6210\u529f\u5219\u8fd4\u56detrue,\u5931\u8d25\u5219\u8fd4\u56defalse.
\ntryRelease(int)\/\/\u72ec\u5360\u65b9\u5f0f\u3002\u5c1d\u8bd5\u91ca\u653e\u8d44\u6e90\uff0c\u6210\u529f\u5219\u8fd4\u56detrue,\u5931\u8d25\u5219\u8fd4\u56defalse.
\ntryAcquireShared(int)\/\/\u5171\u4eab\u65b9\u5f0f\u3002\u5c1d\u8bd5\u83b7\u53d6\u8d44\u6e90\u3002\u8d1f\u6570\u8868\u793a\u5931\u8d25;0\u8868\u793a\u6210\u529f\uff0c\u4f46\u6ca1\u6709\u5270\u4f59\u53ef\u7528\u8d44\u6e90;\u6b63\u6570 \u8868\u793a\u6210\u529f\uff0c\u4e14\u6709\u5270\u4f59\u8d44\u6e90\u3002
\ntryReleaseShared(int)\/\/\u5171\u4eab\u65b9\u5f0f\u3002\u5c1d\u8bd5\u91ca\u653e\u8d44\u6e90\uff0c\u6210\u529f\u5219\u8fd4\u56detrue,\u5931\u8d25\u5219\u8fd4\u56defalse\u3002
\n1\u3001\t\u4ee5ReentrantLock\u4e3a\u4f8b\uff0cstate\u521d\u59cb\u5316\u4e3a0,\u8868\u793a\u672a\u9501\u5b9a\u72b6\u6001\u3002A\u7ebf\u7a0block()\u65f6\uff0c\u4f1a\u8c03\u7528 tryAcquire()\u72ec\u5360\u8be5\u9501\u5e76\u5c06state+1\u3002\u6b64\u540e\uff0c\u5176\u4ed6\u7ebf\u7a0b\u518dtryAcquire0\u65f6\u5c31\u4f1a\u5931\u8d25\uff0c\u76f4\u5230A \u7ebf\u7a0bunlock()\u5230state=0 (\u5373\u91ca\u653e\u9501)\u4e3a\u6b62\uff0c\u5176\u5b83\u7ebf\u7a0b\u624d\u6709\u673a\u4f1a\u83b7\u53d6\u8be5\u9501\u3002\u5f53\u7136\uff0c\u91ca\u653e\u9501\u4e4b\u524d, A\u7ebf\u7a0b\u81ea\u5df1\u662f\u53ef\u4ee5\u91cd\u590d\u83b7\u53d6\u6b64\u9501\u7684(state\u4f1a\u7d2f\u52a0)\uff0c\u8fd9\u5c31\u662f\u53ef\u91cd\u5165\u7684\u6982\u5ff5\u3002\u4f46\u8981\u6ce8\u610f\uff0c\u83b7\u53d6 \u591a\u5c11\u6b21\u5c31\u8981\u91ca\u653e\u591a\u4e48\u6b21\uff0c\u8fd9\u6837\u624d\u80fd\u4fdd\u8bc1state\u662f\u80fd\u56de\u5230\u96f6\u6001\u7684\u3002
\n2\u3001\t\u518d\u4ee5CountDownLatch\u4ee5\u4f8b\uff0c\u4efb\u52a1\u5206\u4e3aN\u4e2a\u5b50\u7ebf\u7a0b\u53bb\u6267\u884c\uff0cstate\u4e5f\u521d\u59cb\u5316\u4e3aN (\u6ce8\u610fN \u8981\u4e0e\u7ebf\u7a0b\u4e2a\u6570\u4e00\u81f4)\u3002\u8fd9N\u4e2a\u5b50\u7ebf\u7a0b\u662f\u5e76\u884c\u6267\u884c\u7684\uff0c\u6bcf\u4e2a\u5b50\u7ebf\u7a0b\u6267\u884c\u5b8c\u540ecountDown() \u4e00\u6b21\uff0c state\u4f1aCAS (Compare and Swap)\u51cfl\u3002\u7b49\u5230\u6240\u6709\u5b50\u7ebf\u7a0b\u90fd\u6267\u884c\u5b8c\u540e(\u5373state=0),\u4f1aunpark()\u4e3b\u8c03\u7528\u7ebf\u7a0b\uff0c\u7136\u540e\u4e3b\u8c03\u7528\u7ebf\u7a0b\u5c31\u4f1a\u4eceawait()\u51fd\u6570\u8fd4\u56de\uff0c\u7ee7\u7eed\u540e\u4f59\u52a8\u4f5c\u3002
\n\u4e00\u822c\u6765\u8bf4\uff0c\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u8981\u4e48\u662f\u72ec\u5360\u65b9\u6cd5\uff0c\u8981\u4e48\u662f\u5171\u4eab\u65b9\u5f0f\uff0c\u4ed6\u4eec\u4e5f\u53ea\u9700\u5b9e\u73b0 tryAcquire-tryRelease\u3001tryAcquireShared-tryReleaseShared \u4e2d\u7684\u4e00\u79cd\u5373\u53ef\u3002
\n\u4f46AQS\u4e5f\u652f\u6301\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u540c\u65f6\u5b9e\u73b0\u72ec\u5360\u548c\u5171\u4eab\u4e24\u79cd\u65b9\u5f0f\uff0c\u5982ReentrantReadWriteLock\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
AQS (AbstractQueuedSynchronizer),\u62bd\u8c61\u961f\u5217\u540c\u6b65\u5668\u3002 AQS\u7684\u540c\u6b65\u72b6\u6001 AQS\u4f7f […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[118],"tags":[],"class_list":["post-9837","post","type-post","status-publish","format-standard","hentry","category-java"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/9837","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=9837"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/9837\/revisions"}],"predecessor-version":[{"id":9838,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/9837\/revisions\/9838"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=9837"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=9837"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=9837"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}