不定长函参的Java观察者模式更新数据传递

灰太狼 2023-08-17 17:37 125阅读 0赞

# 不定长函参的Java观察者模式更新数据传递 #

import java.util.LinkedList;
    
    /**
     * 抽象被观察者。
     * 
     * @param <T>
     */
    public abstract class Subject<T> {
        private LinkedList<Observer> observers;
    
        public Subject() {
            observers = new LinkedList<>();
        }
    
        public Subject getSubject() {
            return this;
        }
    
        public void registerObserver(Observer observer) {
            observers.add(observer);
        }
    
        public void removeObserver(Observer observer) {
            observers.remove(observer);
        }
    
        public void notifyObserver(T... t) {
            for (Observer observer : observers) {
                observer.update(getSubject(), t);
            }
        }
    }

/**
     * 抽象观察者。
     * @param <T>
     */
    public interface Observer<T> {
        void update(Subject subject, T... t);
    }

--------------------

public class State extends Subject {
        @Override
        public Subject getSubject() {
            return this;
        }
    }

public class ObserverImpl implements Observer<Object> {
        @Override
        public void update(Subject subject, Object... objects) {
            StringBuffer sb = new StringBuffer();
            for (Object o : objects) {
                sb.append(o.toString() + ",");
            }
    
            System.out.println("观察到更新:" + sb.toString());
        }
    }

测试：

Subject subject = new State();
            Observer observer = new ObserverImpl();
    
            subject.registerObserver(observer);
    
            new Thread(new Runnable() {
                @Override
                public void run() {
                    int i = 0;
    
                    while (true) {
                        try {
                            TimeUnit.SECONDS.sleep(1);
    
                            subject.notifyObserver((i++)+"",(i++)+"");
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }
            }).start();

输出：

观察到更新:0,1,
    观察到更新:2,3,
    观察到更新:4,5,
    观察到更新:6,7,
    观察到更新:8,9,
    观察到更新:10,11,