Java并发学习之十五——使用读写锁同步数据访问

package chapter2;

import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

public class PricesInfo {
private int price1;
private int price2;
private ReadWriteLock lock;
public PricesInfo(){
price1 = 1;
price2 = 1;
lock = new ReentrantReadWriteLock();

}
public int getPrice1() {
lock.readLock().lock();
int value = price1;
lock.readLock().unlock();
return value;
}
public void setPrice1(int price1) {
this.price1 = price1;
}
public int getPrice2() {
lock.readLock().lock();
int value = price2;
lock.readLock().unlock();
return value;
}
public void setPrice2(int price2) {
this.price2 = price2;
}

public void setPrices(int price1,int price2){
lock.writeLock().lock();
this.price1 = price1;
this.price2 = price2;
lock.writeLock().unlock();
}
}

package chapter2;

public class Reader implements Runnable{

private PricesInfo pricesInfo;
public Reader(PricesInfo pricesInfo){
this.pricesInfo = pricesInfo;
}
@Override
public void run() {

for(int i=0;i<10;i++){

System.out.printf("%s:Price 2:%d\n", Thread.currentThread().getName(),pricesInfo.getPrice2());
System.out.printf("%s:Price 1:%d\n", Thread.currentThread().getName(),pricesInfo.getPrice1());
}

}
}

package chapter2;

import java.util.Random;

public class Writer implements Runnable{
private PricesInfo pricesInfo;
public Writer(PricesInfo pricesInfo){
this.pricesInfo = pricesInfo;
}
@Override
public void run() {

for(int i=0;i<3;i++){
int p1 = new Random().nextInt(47);
int p2 = new Random().nextInt(47)*10;

System.out.println("Writer:Attempt to modify the prices."+p1+"    price2:"+p2);
pricesInfo.setPrices(p1, p2);
System.out.println("Writer:Prices have been modified."+p1+"    price2:"+p2);
try {
Thread.sleep(2);
} catch (Exception e) {
// TODO: handle exception
}
}
}
}

package chapter2;

public class Main6 {

/**
* <p>
* </p>
* @author zhangjunshuai
* @date 2014-9-17 上午11:17:50
* @param args
*/
public static void main(String[] args) {

PricesInfo pricesInfo = new PricesInfo();
Reader reader[] = new Reader[5];
Thread threadsReader[] = new Thread[5];
for (int i = 0; i < threadsReader.length; i++) {
reader[i] = new Reader(pricesInfo);
threadsReader[i]=new Thread(reader[i]);
}
Writer writer = new Writer(pricesInfo);
Thread threadWriter = new Thread(writer);
for (int i = 0; i < threadsReader.length; i++) {
threadsReader[i].start();
}
threadWriter.start();
}

}