一手遮天 Android - 锁和并发处理: Lock 演示 ReentrantLock 的使用_app

概述项目地址https://github.com/webabcd/AndroidDemo作者webabcd一手遮天Android-锁和并发处理:Lock演示ReentrantLock的使用示例如下:/concurrent/ReentrantLockDemo1.java/***ReentrantLock实现了Lock接口，关于Lock的相关知识点请参见“concurrent.LockDemo

项目地址 https://github.com/webabcd/AndroidDemo
作者 webabcd

一手遮天 AndroID - 锁和并发处理: Lock 演示 reentrantlock 的使用示例如下:

/concurrent/reentrantlockDemo1.java

/** * reentrantlock 实现了 Lock 接口，关于 Lock 的相关知识点请参见“concurrent.LockDemo1”, “concurrent.LockDemo2”, “concurrent.LockDemo3” *     顾名思义，reentrantlock 是可重入锁，也就是说 reentrantlock 可以递归调用，即支持嵌套 * * reentrantlock *     new reentrantlock(boolean fair) - 实例化 reentrantlock 并指定其是否为公平锁，默认是非公平锁 *         公平锁 - 按照请求锁的顺序来获取锁 *         非公平锁 - 是否能获取到锁与请求锁的顺序无关 *     isFair() - 是否是公平锁 *     isLocked() - 是否持有锁 *     hasQueuedThreads() - 锁等待队列中是否有线程在等待锁 *     hasQueuedThread(Thread thread) - 指定的线程是否存在于锁等待队列中 *     getQueueLength() - 锁等待队列中的等待线程数 *     isHeldByCurrentThread() - 当前线程是否持有此锁 *     getHoldCount() - 当前线程持有此锁的数量（是数量，而不是次数。比如嵌套锁时，当前线程持有此锁的数量就可能会大于 1） *         // 举个例子如下： *         try { *             _reentrantlock.lock(); *             _reentrantlock.getHoldCount(); // 当前线程持有此锁的数量为 1 *             try { *                 _reentrantlock.lock(); *                 _reentrantlock.getHoldCount(); // 当前线程持有此锁的数量为 2 *             } finally { *                 _reentrantlock.unlock(); *             } *         } finally { *             _reentrantlock.unlock(); *         } *     hasWaiters(Condition condition) - 是否有线程在等待指定的 condition *     getWaitQueueLength(Condition condition) - 返回等待指定的 condition 的线程数 */package com.webabcd.androIDdemo.concurrent;import androID.os.SystemClock;import androIDx.appcompat.app.AppCompatActivity;import androID.os.Bundle;import androID.Widget.TextVIEw;import com.webabcd.androIDdemo.R;import java.util.concurrent.locks.reentrantlock;public class reentrantlockDemo1 extends AppCompatActivity {    private TextVIEw _textVIEw1;    private reentrantlock _reentrantlock = new reentrantlock(false);    @OverrIDe    protected voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_concurrent_lockdemo1);        _textVIEw1 = (TextVIEw) findVIEwByID(R.ID.textVIEw1);        sample();    }    private voID sample() {        for (int i = 0; i < 5; i++) {            Thread thread = new MyThread("thread" + i);            thread.setDaemon(true);            thread.start();        }    }    private class MyThread extends Thread {        public MyThread(String name){            super(name);        }        @OverrIDe        public voID run() {            for (int i = 0; i < 5; i++) {                SystemClock.sleep(10);                _reentrantlock.lock();                try {                    SystemClock.sleep(10);                    writeMessage(String.format("%b, %b, %b, %d, %b, %d",                            _reentrantlock.isFair(),                            _reentrantlock.isLocked(),                            _reentrantlock.hasQueuedThreads(),                            _reentrantlock.getQueueLength(),                            _reentrantlock.isHeldByCurrentThread(),                            _reentrantlock.getHoldCount()));                } catch (Exception ex) {                } finally {                    _reentrantlock.unlock();                }            }        }    }    private voID writeMessage(final String message) {        final String threadname = Thread.currentThread().getname();        runOnUiThread(new Runnable() {            @OverrIDe            public voID run() {                _textVIEw1.append(String.format("%s（%s）\n", message, threadname));            }        });    }}

/layout/activity_concurrent_lockdemo1.xml

<?xml version="1.0" enCoding="utf-8"?><linearLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"    androID:layout_wIDth="match_parent"    androID:layout_height="match_parent"    androID:orIEntation="vertical">    <TextVIEw        androID:ID="@+ID/textVIEw1"        androID:layout_wIDth="wrap_content"        androID:layout_height="wrap_content" /></linearLayout>