package com.imooc.concurrent.racecondition;/*** 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 SetlockObj.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 com.imooc.concurrent.racecondition;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 com.imooc.concurrent.racecondition;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();}}}
