android中和c++中生产者和消费者模式

首先上代码&＃xff0c;android

package com.wmz.helloworld;
import java.util.Random;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class Demo extends android.app.Activity {private class Token {private String flag;public Token() {setFlag(null);}public void setFlag(String flag) {this.flag &＃61; flag;}public String getFlag() {return flag;}}private Token token &＃61; null;&＃64;Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.demo);Button btn &＃61; (Button) findViewById(R.id.button1);token &＃61; new Token();if(token.getFlag() &＃61;&＃61;null)Log.v("A","the token flag value is null");elseLog.v("A","the token flag value is"&＃43;token.getFlag());btn.setOnClickListener(new OnClickListener() { public void onClick(View v) {// TODO Auto-generated method stubWorkThread workthread &＃61; new WorkThread();workthread.start(); Random r&＃61;new Random();for (int i &＃61; 0;i<10; i&＃43;&＃43;) {try { Thread.sleep((r.nextInt(9)&＃43;1)*1000); //增加不确定性,至少睡眠1秒} catch (InterruptedException e) {e.printStackTrace();}synchronized (token) {token.setFlag("wangmz"&＃43;Integer.toString(i));token.notifyAll();Log.v("Main",Integer.toString(i));} }}}); }private class WorkThread extends Thread {&＃64;Overridepublic void run() {Random r&＃61;new Random();while (true) {
// try {
// Thread.sleep((r.nextInt()&＃43;1)*1000);//可能在sleep的时候其他线程执行notify()。但此时对这个线程不起作用。所以结果不会按顺序出现
// } catch (InterruptedException e1) {
// e1.printStackTrace();
// }synchronized (token) {try {token.wait();Log.v("Main", "the value is " &＃43; token.getFlag());} catch (InterruptedException e) {e.printStackTrace();}}Log.v("work","while!!");}}}
}


c&＃43;&＃43;中实现

std::mutex img_mutex_;
std::condition_variable img_cv_;cv::Mat camera::grapPicture()
{std::unique_lock lk(img_mutex_);img_cv_.wait(lk,[this]{return this->isReady_;});cv::Mat temp&＃61; img_.clone();std::cout<<"grap picture,img size:"<}void camera::work_loop()
{while(isRunning){{std::lock_guard lk(img_mutex_);(*capture_)>>img_;isReady_&＃61;true;}img_cv_.notify_one();if(onpreviewcb_)onpreviewcb_(img_);//if here don&＃39;t sleep,this thread will lock img_mutex_ in all most time,and grapPicture will have not chance to grap imagestd::this_thread::sleep_for(std::chrono::milliseconds(10));}std::cout<<"camera:work_loop end"<}

可以看到&＃xff0c;两者基本是一样的&＃xff0c;消费者首先要获得同步锁&＃xff0c;然后wait&＃xff08;wait内部会释放同步锁&＃xff09;&＃xff0c;生产者这时候获得同步锁&＃xff0c;生产数据&＃xff0c;notify&＃xff0c;释放同步锁&＃xff08;如果不释放&＃xff0c;消费者是无法执行的&＃xff09;&＃xff0c;这时候消费者在wait处又可以开始执行了。