package bxjg;
/**
* 宇宙的能量系统
* 遵循能量守恒定律：
* 能量不会凭空创生或消失，只会从一处转移到另一处
*/
public class EnergySystem {
//能量盒子，能量存贮的地方
private final double[] energyBoxes;
private final Object lockObj = new Object();
/**
*
* @param n 能量盒子的数量
* @param initialEnergy 每个能量盒子初始含有的能量值
*/
public EnergySystem(int n, double initialEnergy){
energyBoxes = new double[n];
for (int i = 0; i < energyBoxes.length; i++)
energyBoxes[i] = initialEnergy;
}
/**
* 能量的转移，从一个盒子到另一个盒子
* @param from 能量源
* @param to 能量终点
* @param amount 能量值
*/
public void transfer(int from, int to, double amount){
synchronized(lockObj){
// if (energyBoxes[from] < amount)
// return;
//while循环，保证条件不满足时任务都会被条件阻挡
//而不是继续竞争CPU资源
while (energyBoxes[from] < amount){
try {
//条件不满足, 将当前线程放入Wait Set
lockObj.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.print(Thread.currentThread().getName());
energyBoxes[from] -= amount;
System.out.printf("从%d转移%10.2f单位能量到%d", from, amount, to);
energyBoxes[to] += amount;
System.out.printf(" 能量总和：%10.2f%n", getTotalEnergies());
//唤醒所有在lockObj对象上等待的线程
// lockObj.notifyAll();
}
}
/**
* 获取能量世界的能量总和
*/
public double getTotalEnergies(){
double sum = 0;
for (double amount : energyBoxes)
sum += amount;
return sum;
}
/**
* 返回能量盒子的长度
*/
public int getBoxAmount(){
return energyBoxes.length;
}
}
package bxjg;
public class EnergyTransferTask implements Runnable{
//共享的能量世界
private EnergySystem energySystem;
//能量转移的源能量盒子下标
private int fromBox;
//单次能量转移最大单元
private double maxAmount;
//最大休眠时间（毫秒）
private int DELAY = 10;
public EnergyTransferTask(EnergySystem energySystem, int from, double max){
this.energySystem = energySystem;
this.fromBox = from;
this.maxAmount = max;
}
public void run() {
try{
while (true){
int toBox = (int) (energySystem.getBoxAmount()* Math.random());
double amount = maxAmount * Math.random();
energySystem.transfer(fromBox, toBox, amount);
Thread.sleep((int) (DELAY * Math.random()));
}
}catch (InterruptedException e){
e.printStackTrace();
}
}
}
package bxjg;
public class EnergySystemTest {
//将要构建的能量世界中能量盒子数量
public static final int BOX_AMOUNT = 100;
//每个盒子初始能量
public static final double INITIAL_ENERGY = 1000;
public static void main(String[] args){
EnergySystem eng = new EnergySystem(BOX_AMOUNT, INITIAL_ENERGY);
for (int i = 0; i <BOX_AMOUNT; i++){
EnergyTransferTask task = new EnergyTransferTask(eng, i, INITIAL_ENERGY);
Thread t = new Thread(task,"TransferThread_"+i);
t.start();
}
}
}
发现问题：
public class Test {
static int i;
public static void main(String[] args) {
for(i=0; i<10; i++){
new Thread(){
public void run(){
System.out.println(i);
}
}.start();
// try {
// Thread.sleep(100);
// } catch (InterruptedException e) {
// e.printStackTrace();
// }
}
}
}
出现结果在意料之外，结果不按顺序输出。似乎牵涉到线程与进城的关系，之后做进一步学习