java多线程-线程交互&互斥&同步

package cn.test.muke;

public class EnergySystem {

    private final double[] energyBoxes;
    private final Object lockObj = new Object();
    
    public EnergySystem(int n,double initEnergy) {
        energyBoxes = new double[n];
        for(int i = 0;i < energyBoxes.length;i++) {
            energyBoxes[i] = initEnergy;
        }
    }
            
    public void transfer(int from,int to,double amount) {
        
        synchronized(lockObj) {
            
            /*if(energyBoxes[from] < amount)
                return;*/
            
            // while循环使得当前无法转移能量的盒子进程等待，以此减小系统开销
            // 阻止他们继续竞争cpu，置于wait set中
            while(energyBoxes[from] < amount) {
                try {
                    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();
            
        }
        
    }
    
    public double getTotalEnergies() {
        double sum = 0;
        for(double amount:energyBoxes)
            sum += amount; 
            
        return sum;
    }
    
    public int getBoxAmount() {
        return energyBoxes.length;
    }
    
}

package cn.test.muke;

public class EnergyTransferTask implements Runnable{
    
    private EnergySystem energySystem;
    private int fromBox;
    private double maxAmount;
    private int DELAY = 10;
    
    public EnergyTransferTask(EnergySystem energySystem, int fromBox, double maxAmount) {
        this.energySystem = energySystem;
        this.fromBox = fromBox;
        this.maxAmount = maxAmount;
    }
    
    public void run() {
        
        while(true) {
            int toBox = (int)(energySystem.getBoxAmount()*Math.random());
            double amount = maxAmount*Math.random();
            energySystem.transfer(fromBox,toBox,amount);
            try {
                Thread.sleep((int)(DELAY*Math.random()));
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
    }
    
}

package cn.test.muke;

public class EnergySystemTest {

    public static final int BOX_AMOUNT = 100;
    public static final double INITIAL_ENERGY = 1000;
    
    public static void main(String args[]) {
        
        EnergySystem es = new EnergySystem(BOX_AMOUNT,INITIAL_ENERGY);
        for(int i = 0;i < BOX_AMOUNT;i++) {
            EnergyTransferTask ett = new EnergyTransferTask(es,i,INITIAL_ENERGY);
            Thread t = new Thread(ett,"TransferThread_"+i);
            t.start();
        }
        
    }
    
}