如何使用Observer模式对线程进行文件监控

Question

我正在尝试将观察者模式实现到我制作的游戏中。当使用线程在战区文件中创建反派时，我想使用观察者模式使用线程创建英雄，并将其添加到同一文件中。villians和英雄使用工厂方法模式创建。关于将HeroCreationMain类链接到观察者模式类，我不确定该何去何从。

Villian Creation

public class VillianCreationMain {
private static Villian villian;
public static void main(String[] args, int userInput) throws IOException {
String fileName = null;
Random randomVillian = new Random();
int amountOfVillians = userInput;
if (amountOfVillians < 7) {
for (int x = 0; x < amountOfVillians; x++) {
int randomGenerator = randomVillian.nextInt(6);
for (int i = 0; i < 5; i++) {
if (randomGenerator == 0 ) {
setVillian(new FlyingVillian());
}
else if (randomGenerator == 1) {
setVillian(new StrongVillian());
}
else if (randomGenerator == 2) {
setVillian(new FastVillian());
}
else if (randomGenerator == 3) {
setVillian(new SmartVillian());
}
else if (randomGenerator == 4) {
setVillian(new FireVillian());
}
else if (randomGenerator == 5) {
setVillian(new IceVillian());
}
try {
writeToFile(getVillian(), i, fileName);
}
catch (IOException e) {
System.out.println(e.getMessage());
}
}
VillianThreads t1 = new VillianThreads(VillianCreationMain.getVillian());
t1.start();
}
}
else {
System.out.println("Please enter a value of less than 7");
}
}
public static void writeToFile(Villian villian, int amountOfVillians, String fileName) throws IOException {
for(int x = 0; x < amountOfVillians; x++) {
//  String parsedInt = Integer.toString(x);
fileName = "battle-zone.ser";
FileOutputStream file = new FileOutputStream(fileName);
ObjectOutputStream oos = new ObjectOutputStream(file);
oos.writeObject(villian);
file.close();
oos.close();
}
}
public static Villian getVillian() {
return villian;
}
public static void setVillian(Villian villian) {
VillianCreationMain.villian = villian;
}
}

英雄创造

public class HeroCreationMain {
private static Hero hero = null;
public static void main(String[] Hero) {
EnemyStatus enemyStatus = new EnemyStatus();
VillianObserver observer1 = new VillianObserver(enemyStatus);
}
public static void readFile() throws IOException, ClassNotFoundException {
@SuppressWarnings("resource")
ObjectInputStream ois = new ObjectInputStream (new FileInputStream("battle-zone.ser"));
Villian targetVillian = (Villian) ois.readObject();
System.out.println(targetVillian + " is being attacked by a hero!");
}
public static Hero getHero() {
return hero;
}
public static void setHero(Hero hero) {
HeroCreationMain.hero = hero;
}
}

观察员

public interface Observer {
public void update(boolean enemyPresent);
}
public interface Subject {
public void register(Observer o);
public void unregister(Observer o);
public void notifyObserver();
}

可观测

public class VillianObserver implements Observer {
private boolean enemyPresent;
private static int heroIDTracker;
private int heroID;
private Subject villianObserver;
public VillianObserver(Subject villianObserver) {
this.villianObserver = villianObserver;
this.heroID = ++heroIDTracker;
System.out.println("New Observer " + this.heroID);
villianObserver.register(this);
}
@Override
public void update(boolean enemyPresent) {
this.enemyPresent = enemyPresent;
printResult();
}
public void printResult() {
System.out.println(heroID + " " + enemyPresent);
}
}

敌人状态

import java.util.ArrayList;
public class EnemyStatus implements Subject {
private ArrayList<Observer> observers;
private boolean enemyPresent;
public EnemyStatus() {
// Creates an ArrayList to hold all observers
observers = new ArrayList<Observer>();
}
@Override
public void register(Observer newObserver) {
observers.add(newObserver);
}
@Override
public void unregister(Observer deleteObserver) {
// Get the index of the observer to delete
int heroIndex = observers.indexOf(deleteObserver);
// Print out message (Have to increment index to match  
System.out.println("Observer " + (heroIndex+1) + " deleted");        
// Removes observer from the ArrayList
observers.remove(heroIndex);

}
@Override
public void notifyObserver() {
for(Observer observer : observers) {
observer.update(enemyPresent);
}
}
public void setEnemyStatus(boolean enemyPresent) {
this.enemyPresent = enemyPresent;
notifyObserver();
}
}  

Answer 1

JNotify是一个Java库，用于观察文件系统上的文件更改。

有一条建议：对象(输入/输出(流在你刚开始的时候很容易，但它们会让你走上毁灭的道路。对象很容易坏版本。对象文件也相对难以使用文本编辑器进行检查。我建议您尝试使用不同的数据格式(如JSON(。